Posters in the Hall

End of Year Annual Event

Undergraduate and Graduate Students Present their Research

 

2017 Undergraduate Student Presenters

James Herbort1 and William Feld1
"Improvements to the synthesis of haplomyrtin and synthesis of a trifluoromethoxy analogue"

James Herbort Poster

1Department of Chemistry, Wright State University, Dayton, OH

Aryl naphthalene natural products have been shown to inhibit HT-29 colon cancer cells in mammals by a method that is dissimilar to the commercially available cancer drug etoposide. Haplomyrtin bears a striking resemblance to many biologically active aryl naphthalene molecules, but it’s potency(or lack thereof) remains untested. A seven-step strategy led to the synthesis of haplomyrtin in a 7% overall yield. The installation of the pendant moiety allows for easy access to different analogues. To evidence this, an analogue was synthesized that contains the very lipophilic trifluoromethoxy group.
 

Don Hoang,1 Selvakumar Jayaraman,1 and Kuppuswamy Arumugam1
"Gold (I) complexes containing alkylated ferrocenes:
The beginning of a new generation of organometallic anti-cancer compounds"  

1Department of Chemistry, Wright State University, Dayton, OHDon Hoang Poster

Implementing redox-active organometallic compounds can increase intracellular reactive oxygen species (ROS) levels, leading to oxidative stress and eventually apoptosis in neoplastic cells. It is hypothesized that reducing the redox potential of the compound would facilitate redox processes, increasing the overall potency of the compound. Accordingly, the goal of the project is to synthesize imidazolinium salts that could allow for tuning of redox potential in ferrocenyl-N-heterocyclic carbene gold (I) complexes. Carbamoyl ferrocene seemed to provide the best route to the desired imidazolinium salts. The next steps are lithiation of carbamoyl ferrocene followed by electrophilic substitution and Friedel-Crafts acylation of carbamoyl ferrocene. Once the imidazolinium salts are prepared, they will be subjected to preparation of gold (I)-N-heterocyclic carbenes.

Catherine E. Smith1 and Kuppuswamy Arumugam1
Catherine E. Smith"Development of synthesis strategy for [bis-(1,3-diferrocenylmethyl-imidazole-2-ylidene)-gold] [tetrafluoroborate]5 "

1Department of Chemistry, Wright State University, Dayton, OH  

The group previously synthesized [Bis(1,3-diferrocenylmethyl-imidazol-2-ylidene)-gold(II)] [chloride]. This compound was observed to kill cancer cells in the body through dual mechanistic pathways, i.e., suppression of anti-oxidative enzyme and non-specific generation of reaction oxygen species. Ferrocene is believed to be involved in catalytic generation of reactive oxygen species. This aim of this project include isolation of oxidized version of [bis(1,3-diferrocenylmethyl-imidazol-2-ylidene)-gold] [tetrafluoroborate] to prove that oxidation occurs at ferrocene center. Therefore a strategy for the synthesis of [bis(1,3-diferrocenylmethyl-imidazol-2-ylidene)-gold(II)] [tetrafluoroborate]5 was developed.

 

Emily L. Warren,1 Audrey McGowin,1 Rebecca E. Teed,2 and Scott Sanders3
"Source Determination of arsenic, lead, and cadmium In the Yellow Spring sediment in Glen Helen Nature Preserve, OH"

1Department of Chemistry, Wright State University, Dayton, OHEmily Warren Poster

2Department of Earth and Environmental Sciences, Wright State University, Dayton, OH

Arsenic, lead, and cadmium have been found at elevated levels in the sediment of the “Yellow Spring” located in Glen Helen Nature Preserve in Yellow Springs, Ohio (A. McGowin, unpublished results). The Yellow Spring is named for the bright orange travertine deposits that are rich in iron.  My research was to determine whether the arsenic, lead, and cadmium in the sediment were occurring naturally in the spring or coming from the pipes that are used in the construction of the man-made structure from which the artesian spring flows. I collected sediment samples from three surrounding sights for comparison. The first three sample sites were the Yellow Spring sediment, the “Grotto” sediment (a waterfall just downstream), and a second site further downstream site. Another site was soil from the root zone of a fallen tree that is also rich in iron, from which three samples were taken. A total of six samples, each sample split into four replicates for analysis. Samples were digested in acid following USEPA Method 3050B and analyzed for iron, arsenic, lead, and cadmium using inductively-coupled plasma-optical emission spectrometry (ICP-OES) following EPA Method 200.7. Statistical analysis of the results indicate that arsenic, lead, and cadmium occur naturally in minerals that are distributed throughout Glen Helen.

 

2017 Graduate Students Presenters

 

Md Ali Akbar1, Arathi Paluri1, 2, and Ioana Sizemore1, 2*
"Cloud point extraction (CPE)  in combination with tangential flow filtration (TFF) for the isolation of silver nanoparticles and ionic silver"

1Department of Chemistry and 2Biomedical Sciences Ph.D. Program, Wright State University, Dayton, OHMd Ali Akbar

The increased use of silver nanoparticles (AgNPs) in a variety of consumer products has amplified their potential release into the environment. Furthermore, AgNPs were found to exert harmful effects on living organisms mostly by producing Ag+ ions and causing oxidative stress. Therefore, it is imperative to develop methods for isolating the two silver species (AgNPs and Ag+) from various matrices. In this study, cloud point extraction (CPE) and tangential flow filtration (TFF) were combined to increase the extraction efficiencies of AgNPs and Ag+ from colloidal and biological matrices. Briefly, a non-ionic surfactant (Triton X-114) and sodium thiosulfate were added to the samples containing AgNPs and incubated over the cloud point temperature of the surfactant to allow for the micelle formation with AgNPs (surfactant phase) and the chelation of Ag+ with thiosulfate (aqueous phase). The two CPE phases were then separated by centrifugation, and the aqueous phase containing mainly Ag+ ions and some AgNPs was further processed through a 1-kD filter to further recover AgNPs. The total concentration of Ag in the two CPE phases and the resulting TFF products, namely permeate (containing Ag+) and retentate (containing AgNPs), were quantified by inductively coupled plasma optical emission spectroscopy (ICP-OES). The versatility of the CPE-TFF method was demonstrated on three different colloids (Creighton, Lee-Meisel, and PVP-capped) and one cellular matrix (human and animal kidney cells). The extraction efficiency of AgNPs and Ag+ ranged from ~65%-88% and 15-28% respectively, while the total Ag recoveries were 81%-96.43%.

Amira M. Alsenbel1 and Audrey E. McGowin,1 Taylor Stuckert,2 Lori Williams,3 and Harry McVey4
"Heavy metals in Lytle Creek and Indian Run"

1Department of Chemistry, Wright State University, Dayton, OHAmira M. Alsenbel Poster

2Clinton County Regional Planning Commission, Wilmington, OH

3City of Wilmington, Parks and Recreation, OH

4City of Wilmington, Wastewater, OH

Limited macroinvtebrate biodiversity in Lytle Creek that runs through downtown Wilmington, OH has been documented over decades with the lowest in Lytle Creek at Sugar Grove Cemetery.  Lytle Creek, a tributary of the Little Miami River, is a conduit for storm water and wastewater from an airpark, downtown storm water with input from local businesses, and a wastewater treatment plant.  This study was conducted to see if heavy metal pollution in the sediment could be a contributing factor in reduced macroinvertebrate populations.  Five sites were sampled in Lytle Creek from the headwaters at Wilmington College to the landfill discharge.  A tributary to Lytle Creek, which runs through downtown at Xidas Park, was added when dead fish were discovered. Two sites were selected in Indian Run, one upstream and one downstream of the airpark’s wastewater treatment facility. Sediments were analyzed for mercury (Hg) using cold vapor atomic fluorescence spectrometry.  Aluminum (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), strontium (Sr), and zinc (Zn) were determined by inductively-coupled optical emission spectrometry (EPA method 200.7). Mercury concentrations ranged from 0.013-0.163 mg/kg dry wt. The highest levels of mercury were found in Xidas Park and in Sugar Grove Cemetery (0.124 and 0.163 mg/kg dry wt., respectively).  Total heavy metals ranged from 0.6-339.5 mg/kg dry wt. .The downtown tributary to Lytle Creek, Xidas Park site, empties into Lytle Creek at Sugar Grove Cemetery indicating lack of biodiversity in Lytle Creek may be caused by runoff into storm drains in downtown Wilmington. 

Gregory Bowers1 and Paul Seybold1
"A Stochastic Cellular Automaton Model of Tautomer Equilibria"
Gregory Bowers Poster

1Department of Chemistry, Wright State University, Dayton, OH 

Tautomer equilibria are complex and dynamic, making modeling them a challenge. Cellular automata models are uniquely suited to address this challenge, allowing the equilibria to arise naturally from simple rules. In this study, a stochastic, asynchronous cellular automata model was employed to simulate the tautomer equilibrium of 9-anthrone and 9-anthrol in the presence of their common anion.  The observed KE of the 9-anthrone ⇌  9-anthrol tautomerization along with the measured tautomer pKa values were used to model the equilibrium at pH values 4, 7, and 10.  At pH values 4 and 7, the anthrone comprised > 99% of the total species population, whereas at pH 10 the anthrone and the anion each represented just under half of the total population. The anthrol population was very small under all conditions.

 
 
Nathaniel Brackett1 and  William Feld1
"Incorporation of 5,8-dioxo-5,8-dihydroindeno-[2,1-c]fluorene into polymeric systems"

1Department of Chemistry, Wright State University, Dayton, OH Nathaniel Brackett

Indenofluorenes 1 show many desirable properties crucial to today’s modern technologies.  They have excellent emission and absorption wavelengths which make them ideal for organic light emitting diodes or organic photovoltaic devices.  They are usually incorporated into polymers by coupling reactions using either nickel or palladium catalysts.  As a complement to those methods, a five-step synthesis resulted in the formation of 3,10-difluoro-5,8-Dioxo-5,8-dihydroindeno-[2,1-c]fluorene 2 that could undergo polymerization by nucleophilic aromatic substitution. Monomer 2 was reacted with p-cresol in a model reaction and with bisphenol-A to produce polymer 3. A discussion of the multiple reaction conditions employing NMP and DMSO in these reactions will be presented.

Brackett Reaction

1 R = alkyl, X = Br                  2                                          3

 

Matthew Cerone1 and William Feld1
"Synthesis of alkyl substituted phenylated poly(ether ether ketone ketone)s"
Matthew Cerone Poster

1Department of Chemistry, Wright State University, Dayton, OH 

Poly(ether ether ketone)s are a much studied polymer family, best suited for use in industries where a resilient, nonreactive material is needed. One issue with PEEK is that it is difficult to process. The rigid structure, functional group polarity and planar aromatic character appear to be responsible. Adding pendent functionality, particularly phenyls, is known to increase solubility and processability. The NAS polymerization of bis(fluorophenyl) monomers 1a and 1b to the corresponding polymers 2a and 2b has been reported and the influence of the additional phenyl substituents documented. The addition of an alkyl chain in monomer 1c led to polymers 2c that exhibited a decrease in Tg with a minimal influence on thermal stability (Td5%). Polymers 2b and 2c were soluble in chloroform and were able to be cast as thin transparent films. A comparison of the properties of polymers 2a-c will be presented.

 

     1a Ar = H, R = H                                     2a Ar = H, R = H

     1b Ar = -Ph, R = H                                  2b Ar = -Ph, R = H

     1c Ar = -Ph, R = -C6H13                           2c Ar = -Ph, R = -C6H13

Kotiba Malek,1 Krushangi Shah,1 Alexander Castillo Guel,1 and Kuppuswamy Arumugam 1
"Redox-active silver N-heterocyclic carbene complexes: A dual targeting anti-bacterial drug"

1Department of Chemistry, Wright State University, Dayton, OHKotiba Malek Poster

Bacterial resistance to current antibiotics necessitates new alternative therapeutic drugs. Silver based drugs are promising in this realm. However, current silver-based antibacterial drugs are limited in their bioavailability due to their rapid release of silver ions. Recently, N-heterocyclic carbene containing silver complexes have gained popularity due to slow release of silver ions under biological conditions. As a result, two new potential antibacterial silver-NHC complexes were synthesized and confirmed via analytical techniques, including 1H and 13C NMR spectroscopy and x-ray crystallography.

 
Sarah A. Jindra,1 Angela L. Bertagni,1 and Steven R. Higgins1
"Hydrothermal atomic force microscopy investigation of barite growth: The role of spectator ions in elementary step edge growth kinetics and hillock morphology

Sarah A. Jindra Poster1Department of Chemistry, Wright State University, Dayton, OH

Mineralization of barite (BaSO4) occurs in various geologic settings where barite scale formation can be problematic. To better understand the role of spectator ions in the aqueous solution growth of barite, the kinetics of elementary step edge growth on barite (001) surfaces have been studied under a wide variety of solution conditions. The results of these studies have been used to determine the effects of various electrolytes on elementary step kinetics. Hydrothermal Atomic Force Microscopy (HAFM) was used to investigate the effect of background electrolytes (NaCl, NaBr and NaNO3) as a function of saturation index, and ionic strength (I) on barite growth sourced at dislocations at 108 oC. Initial results show that hillock morphology is affected by I. The effect of increasing I on hillock morphology was observed in 0.05 M NaCl, but the effect was absent in 0.05 M NaNO3, suggesting a specific interaction of Cl- with the polar [010] step edge in contrast to NO3-. The step rate coefficient increased when I was increased in NaCl solutions. Initial results for NaNO3 further indicate an ionic strength effect on rate coefficients, however, the coefficients for NaCl tended to be larger than the NaNO3 coefficient, possibly indicating an inhibitory role of nitrate towards the advancement of the non-polar 〈120〉 steps. These results indicate that I is a driver of hillock morphology in the instances where NaCl is the electrolyte. However, in the case of NaNO3 there is no clear driver for the morphology.

Christine Kinstedt1 and Daniel Ketcha1
"Extended conjugated chalcones as theranostic agents in Alzheimer’s research" Christine Kinstedt

1Department of Chemistry, Wright State University, Dayton, OH

The term “theranostics” has been coined to describe certain classes of molecules which have the potential to serve as therapeutic as well as diagnostic agents. One such class of substrates includes chalcones, which due to their ability to cross the blood brain barrier (BBB), have demonstrated efficacy in a number of neurodegenerative diseases and constitute a convenient starting point for the development of multi-target agents for Alzheimer’s disease (AD) (e.g., amyloid aggregation and acetylcholinesterase inhibitors). Additionally, previous research has indicated that the extending the conjugation in molecules that bind to amyloid-beta (Ab) plaques (e.g., Pittsburgh B, benzylidene oxindoles, etc) results in enhanced selectivity towards the more diagnostically relevant tau aggregates. Since simple chalcones have been demonstrated to serve as positron emission tomography (PET) imaging agents for detecting Ab plaques, we are now investigating the use of “extended conjugation” analogues in the expectation that such substrates should prove valuable for targeting tau and/or alpha-synuclein aggregates of significance in Parkinson’s disease (PD), while retaining the aforementioned therapeutic effects. Moreover, these extended analogues exhibit enhanced fluorescent properties which make them candidates for the detection of the aforementioned plaques by less costly Near Infrared (NIR) methods. This research details explorations of novel structural modifications of the chalcone scaffold which result in Ab aggregation inhibition and differential binding to the plaques of relevance to AD and PD, allowing for the detection of such biomarkers by PET or NIR approaches

Meredith Miles,1 Rebecca McCall,2 Jannet Kocerha,2 Kevin Sidoran,3 Jonathan F. Arambula,2,4 and Kuppuswamy Arumugam1
"Development of N-heterocyclic carbene-gold(I) complexes for therapeutic applications"

1Department of Chemistry and 2Biomedical Sciences Ph.D. Program, Wright State University, Dayton, OH, 45435  Meredith Miles

2Department of Chemistry, Georgia Southern University, Statesboro, GA 30460

3Department of Chemistry, St. Bonaventure University, St. Bonaventure, NY 14778

4Department of Chemistry, University of Texas, Austin, TX 78712-1224

The tunable steric and electronic properties of N-heterocyclic carbenes (NHCs) coupled with their σ-donating abilities allow for excellent coordination to transition metal complexes. NHC-gold(I) complexes have shown promise as cancer treatment drugs because of their ability to target thiol-functional groups found in the Thioredoxin Reductase (TrxR) system. Our previous work has proven that generating reactive oxygen species (ROS) and inhibiting the TrxR system simultaneously induces apoptosis. Hence, modifying the N-substituents and fusing the NHC-gold(I) complex with naphthoquinone further enhanced this oxidative-stress pathway to kill the tumor cells. Three naphthoquinone fused NHC-gold(I) complexes were synthesized and confirmed structurally with 1H and 13C NMR, UV-Vis spectroscopy, IR spectroscopy, and X-ray crystallography. The redox properties of the complexes were confirmed with various electrochemical techniques. Cell proliferation studies were also performed to determine the efficacy of the complexes.

 

Joel R. Schmitz1 and David. A Dolson1
"Relaxation kinetics of nitrosyl bromide (BrNO)"

1Department of Chemistry, Wright State University, Dayton, OH Joel Schmitz Poster

The gas phase reaction of bromine and nitric oxide to produce nitrosyl bromide, , has importance in atmospheric kinetic modeling and in the chemistry of an infrared NO (v=2®1 ) laser that is excited by E-V energy transfer from spin-orbit excited Br*(2P1/2) atoms arising from photolysis of Br2.  

Previous studies of this reaction have employed methods such as laser photolysis and pseudo first- or second-order kinetics. This present research investigation has used two experimental methods.  One is to mix the two reactants and fit the early time reaction observations to a third-order integrated rate law for only the forward reaction.  The second, relaxation kinetics method, imposes an “instantaneous” perturbation on the reaction initially at equilibrium, and then monitors the reaction system’s return to equilibrium.  The time dependence of the equilibrium approach can yield the forward and reverse rate coefficients for the reaction.  In this work a rapid volume expansion of the equilibrium gas mixture serves as the perturbation.  In both methods, the equilibrium constant of the formation of BrNO is determined from equilibrium partial pressures. The forward rate coefficient determined from early time observations of the formation reaction, kf =1.55(5) x 10-5 torr-2·s-1, combined with the equilibrium constant, K = 0.26(3) torr-1, yielded a reverse rate coefficient, kr = 6.4(6) x 10-5 torr-1·s-1. Agreement with literature is good (kf = 1.6(2) x 10-5 torr-2·s-1, kr = 7(1) x 10-5 torr-1·s-1, K = 0.23(2) torr-1), demonstrating the validity of this experimental method. Relaxation kinetics results are included in the poster.

 

Kraig E. Strayer,1 Heather M. Antonides,2 Matthew P. Juhascik,2* Raminta Daniulaityte,3 and Ioana E. Sizemore1
"A LC-MS/MS-Based Method for the Multiplex Detection of Fentanyl Analogs in Biological Matrices at Sub ng mL-1

Kraig Strayer Poster

Concentrations"

1Department of Chemistry and 3Department of Population and Public Health Sciences, Wright State University, Dayton, OH

2Montgomery County Coroner’s Office, Dayton, OH

Fentanyl, a synthetic opioid, is commonly prescribed for chronic pain management but comes with a high potential for illegal abuse. Lately, a surge of fentanyl-related overdose deaths has risen to epidemic numbers both regionally and nationally. Thus, there is a great need of developing recognition methods for the various fentanyl analogs and their metabolites in human specimens. In this project, we have developed an LC-MS/MS based method for the multiplex detection of 22 fentanyl analogs. Validation samples were made at various concentrations for calibrators and controls were extracted using UCT Clean Screen SPE filters. Extraction samples were then eluted with methylene chloride/isopropanol/ammonium hydroxide (78:20:2), evaporated, and reconstituted with 100 µL of MeOH, before analysis by LC-MS/MS using a biphenyl column with a run time of 13.5 minutes. Method parameters validated were linearity, bias, precision, matrix effects, recovery, process efficiency, limit of detection, and lower limit of quantitation. Calibration ranges for most analytes were from 0.1 ng mL-1 to 10 ng mL-1 except for fentanyl and norfentanyl where the upper range limit was expanded to 50.0 ng mL-1. A novel LC-MS/MS-based method was developed for the identification and/or quantification of fentanyl analogs and metabolites (N = 22) and is currently employed for the fentanyl analysis of post-mortem and DUI samples at the Montgomery County Coroner’s Office.

 

Richard A. Williams III1 and Rachel S. Aga1
Richard A. Williams Poster"Adsorption of Fullerenes on Alumina: A Molecular Simulation Study"

1Department of Chemistry, Wright State University, Dayton, OH 

From drug delivery to solar cells, fullerene molecules and their derivatives are being utilized for applications in a variety of technologies. They are poised to become increasingly important in the future of science and engineering. With the increased use of these molecules, it is important to investigate how they will interact with other natural materials to understand their potential impact on the environment. We explore the adsorption behavior of C60 and C70 molecules on alumina, a common mineral in the environment, though the use of molecular simulations. With this technique, we aim to provide a molecular-level understanding of the properties at the nanomaterial-mineral interface. Simulations consisting of a series of geometry optimizations and molecular dynamics were carried out using Materials Studio. We report density profiles and adsorption energies as a function of nanomaterial concentration. The trend in the adsorption energy is consistent with the local ordering of the fullerenes at the interface.  It was observed that clustering appears to be favorable for both molecules, as the adsorption energy decreased with increasing density. Simulations with water were also carried out, and we find that the density distributions of the fullerenes near the mineral surface are altered by the presence of water.

 

 

2015

Undergraduate Student Presenter

Yiscka Gooijer,
Determination of minor and trace impurities in barite minerals with ICP-OES

Yiscka Gooijer1.2, Jacquelyn N. Bracco2 and Steven R. Higgins2
1)  Hogeschool Utrecht, Institute for Life Sciences and Chemistry, Utrecht, the Netherlands
2)  Department of Chemistry, Wright State University, Dayton, Ohio, USA

The goal of this project is to develop a method to determine minor and trace impurities in barite minerals with inductively coupled plasma – optical emission spectrometry (ICP-OES). Barite is a mineral composed of barium sulfate (BaSO4) and  naturally precipitates on the bottom of the ocean which leads to sediments. Due to unfavorable thermodynamics and kinetics of dissolution, barite is only sparingly soluble in water or concentrated nitric acid. The first step in this project was making a digesting method for barite. Chelating agents, such as ethylenediaminetetraacetic acid (EDTA) can form strong complexes with metal ions, such as Ba2+, in solution at a high pH. Experiments were carried out over a range of EDTA concentrations (1.0 – 50 mM solutions, pH≈13), at room temperature (22°C), as well as at 80 °C.  These experiments show that the total dissolved barite increases with an increasing concentration of EDTA and a higher temperature (80°C). By using a hot plate to heat and stir, a higher concentration of Ba2+ is obtained when compared to the use of an ultrasonic bath. The second step in the project is to analyze the minor and trace impurities in barite. The barite analyzed using this methodology consisted  of 0.013 % (m/m) calcium, 0.0063 % (m/m) strontium, 0.0016 %  (m/m) magnesium and 0.0012 % (m/m) iron.

Graduate Student Presenters

Seth Brittle,
Measuring total silver in nanosilver colloids by inductively coupled plasma optical emission spectroscopy:  a laboratory experiment for chemistry and engineering students

Seth Brittle, Joshua Baker, Kevin Dorney, Tala Ebrahimian, Jessica Dagher, Steven Higgins, Ioana Pavel Sizemore,Brittle, Seth
Department of Chemistry, Wright State University, Dayton, Ohio, United States

The proliferation of nanoscience and nanotechnology is expected to create over six million nano-related jobs by 2020. To help meet this educational need, a novel nano-laboratory experiment was developed and carried out in two upper-level laboratory courses at WSU: Experimental Nanomaterials and Nanoscience and Instrumental Analysis. The main objective was to accurately quantify the total silver content of widely-used Creighton colloids by inductively coupled plasma optical emission spectroscopy (ICP-OES). Undergraduate and graduate students estimated the total silver amount via the external calibration (16.3 ± 4.7 mg L-1) and the standard addition method (14.9 ± 4.2 mg L-1) at two emission wavelengths (328.068 nm and 338.898 nm). It was found that the standard additions method generates more accurate results when compared to the theoretical yield of the reaction (15.4 mg L-1) due to consideration of matrix effects. An average percent error of 3.2% was observed for the standard additions approach, while the external calibration method had an average percent error of 8.3%. The instructor evaluation of basic laboratory skills and the class assignments showed that the students successfully mastered the various aspects of samples/standards preparation, the operation of modern ICP-OES instrumentation, and the data analysis. Overall, the educational aspects associated with this novel laboratory experiment for science and engineering students were highly rated in student evaluations.

Daniel P. Foose ,
Vespucci: A spectroscopic analysis software package

Daniel P. Foose, Adam C. Stahler, Ioana E. P. SizemoreDan Foose
Department of Chemistry, Wright State University

A software package has been developed for the analysis and imaging of large spectroscopy datasets with and without spatial and temporal data. Vespucci is capable of several analysis techniques, including univariate and multivariate analysis and imaging. Vespucci also performs several common pre-processing methods such as normalization and baseline correction. Vespucci was written primarily with a focus on Raman spectroscopy, but is capable of handling other kinds of chemical data, including IR spectroscopy and mass spectrometry, provided that the data can be expressed in a plain text file.  Additional pre-processing and analysis methods can be performed using an R interface. The software has been successfully used to analyze the occurrence of Raman signals related to specific functional groups in a number of large spectral-spatial datasets. Vespucci is free software distributed under the terms of the GNU General Public License.

Anna Foote,
Influence of solvents on the physical properties of materials for organic photovoltaic devices

Anna L. Foote 1, Eric Niwemukiza1, Michael J.Goldcamp2, and Rachel S. Aga1 Anna Foote
1
Wright State University, Department of Chemistry 3640 Colonel Glenn Highway, Dayton, OH 45435
2Wilmington College, Department of Chemistry and Physics 1870 Quaker Way, Wilmington, OH 45177

Implementation of various fabrication techniques, specifically solvent annealing and solvent additives, has led to improved efficiencies of organic photovoltaic devices. This is in part due to effects of solvents on the physical properties of polymer donor films. To gain a basic understanding of the role of solvents in influencing absorption, surface tension, and bandgap of organic films, we present a comparative study of donor-acceptor blends in different solvent and solvent mixtures. Investigations have been carried out for P3HT (poly(3-hexylthiophene)), PTB7 (polythieno[3,4-b]-thiophene-co-benzodithiophene), PC61BM (C61-butyric acid methyl ester), and PB71BM (C71-butyric acid methyl ester). The physical properties reported are based on UV-Vis spectroscopy, optical tensiometry, and cyclic voltammetry measurements of the organic films. The solvents used to prepare the organic films are chlorobenzene and 1,2-dichlorobenzene, with and without 1,8-diiodooctane as an additive.

Kara L. Geremia,
Reactivity Ratio Controlled Polycondensation as a Route to Functional Poly(arylene ether ketone)s
and Computational Estimation of the pKas of Purines

Reactivity Ratio Controlled Polycondensation as a Route to Functional Poly(arylene ether ketone)s

Kara Geremia and Dr. Eric FossumKara Geremia
Chemistry Department, Wright State University

There are two methods for introducing functional groups to poly(arylene ether)s, PAEs, in particular poly(arylene ether ketone)s, which are typically prepared via nucleophilic aromatic substitution, NAS.  The first method involves the synthesis of functionalized monomers “pre” to the polymerization process.  The second method installs the functional groups “post” to the formation of the polymer. It is of interest to design a single monomer that allows either the preparation of functional monomers in situ, followed by subsequent polymerization or preparation of the polymer followed by modification. This presentation describes our efforts to utilize reactivity differences in 3,5,4’-trifluorobenzophenone (1), to prepare functional poly(arylene ether ketone)s via a one-pot procedure. Kinetic studies afforded the activation energies for the three different fluoride reactive sites.  The kinetic parameters were then applied to the polymerization of 1, acting as a B2-type monomer, with Bisphenol-A to provide a polymer carrying the third fluorine site for “post” modification.

Computational Estimation of the pKas of Purines

Kara L. Geremia and Paul G. Seybold
Chemistry Department, Wright State University

The acid dissociation value pKa of a compound provides important information regarding the neutral and ionic forms of the compound present under different conditions.  However, for many compounds experimental pKa values are not available, and for others the measured values are sometimes uncertain.  Consequently, having a computational means for estimating pKa values can be of benefit for biochemical, pharmaceutical, polymer, and many other studies.  Purines form a key group of bioactive compounds whose acid/base activities are of considerable interest.  The purine class includes such diverse compounds as the nucleic acid bases adenine and guanine, the gout-related compound uric acid, the stimulant caffeine, and the leukemia drug 6-mercaptopurine.  We have developed a computational method for estimating purine pKas using a quantitative structure property relationship (QSAR) approach.  A group of 25 purines and related compounds was first assembled and then examined using the semi-empirical quantum chemical method RM1.  This was followed by an ab initio analysis based on density functional theory and the functional defined by Becke, Lee, Yang, and Parr with the basis set 6-31+G**.

Shannon Hennelly,
Polymerization of PEEK AB monomers with oxyalkylene linkages via NAS and Friedel-Crafts reactions

Shannon Hennelly and William FeldShannon Hennelly
Department of Chemistry, Wright State University

Poly(ether ether ketone)s (PEEK) have unique thermal stability, solvent resistance and mechanical properties. Since the original synthesis of PEEK, many modifications have been made to enhance their properties. Previously, PEEK monomers having oxyalkylene linkages were synthesized and polymerized in typical AA + BB polymerization reactions using NAS conditions. Two AB versions of these monomers (4-fluorophenyl)(4-(2-(4-hydroxyphenoxy)-ethoxy)-phenyl)methanone and 4-(2-(4-phenoxyphenoxy)ethoxy)benzoic acid have been synthesized and polymerized by typical NAS (Potassium Carbonate, Toluene, NMP) and Friedel-Crafts (MSA, Phosphorous Pentoxide) procedures, respectively.

Hennelly 1.jpg

Carly Jordan,
Work function modification of metal electrodes by deposition of carbon nanotubes and PEDOT:PSS via aerosol jet printing

Carly A. Jordana, Roberto S. Aga, Jr.b, Eric Kreitb, Carrie M. Bartschb, Emily M. Heckmanb, and Rachel S. Agaa Carly Jordan

aWright State University, Department of Chemistry, 3640 Colonel Glenn Hwy.,  Dayton, OH 45435
bAir Force Research Laboratory, Sensors Directorate,Wright-Patterson AFB, OH 45433

Organic electronic devices could benefit from electrodes with tunable work functions.  In this work, modification of work function is achieved by deposition of thin films of carbon nanotubes or PEDOT:PSS on nickel via aerosol jet printing.  We show that the resulting work function exhibits dependence on the thickness of the CNT or PEDOT:PSS layer and the underlying metal. Ambient Kelvin probe was employed to characterize the effective work function.  The thickness of the printed films were determined by surface profilometer.  By modifying the work function, the metal/organic semiconductor interface is also altered.  We evaluate the effect of this change on device performance by using the PEDOT:PSS-coated electrodes to fabricate Schottky photodetectors, employing a poly(3-hexylthiophene):C61-butyric acid methyl ester (P3HT:PC61BM) composite.

Amanda Lock,
Methods for N-Alkylation of Benzylidene Oxindoles

Kyle J. Knisley, Kaleb W. Cox, Amanda Lock, and Daniel M. KetchaAmanda Lock Boyer
Wright State University

Given the ambident reactivity of oxindoles in terms of N- versus C-alkylation, realization of the three points of diversity available to (presumably benzenoid substituted) benzylidene oxindoles is normally achieved via a sequence involving initial N-alkylation of the corresponding isatin precursor, reductive deoxygenation to the N-alkylated oxindole, and finally aldol condensation to the desired target. Since benzenoid substituted isatins are generally more readily available than the corresponding oxindoles, an alternate but much less examined manifold involves reduction of the isatin to an oxindole, aldolization followed by N-alkylation of the resultant benzylidene oxindole. In light of the fact that arylidene oxindoles have most often been studied as kinase inhibitors, wherein the presence of the CO-NH moiety is critical for activity, it is not surprising that the three points of diversity offered by N-alkylation of this scaffold is rarely exploited for drug discovery purposes. Since arylidene oxindoles have potential beyond that of kinase inhibitors, one of the goals of our research program has been to develop expedited methods for their preparation while being amenable to multi-parallel synthesis. An overarching stratagem of this design concept was to achieve these goals through a libraries from libraries approach, wherein sub-libraries of precursor compounds could be prepared and screened for alternative applications before subjecting these compounds to further elaboration for subsequent screens in terms of other applications. The N-alkylation of benzylidene oxindoles is a reaction that has seen only limited usage and sometimes as the first step in a multi-step sequence (without isolation or characterization of the initial alkylated product). We find that the N-alkylation of benzylidene oxindoles with benzylic or propargylic halides can be effected using either of three bases; the soluble liquid base K2CO3/DMF, solid supported KF/alumina, or DBU in ethanol.

Lainey Mallin,
Proxy-PET Building Blocks as a Design Element for Library Synthesis

Lainey Mallina ; Hans de Kraker, Stephanie S. Huthmacher, Daniel M. Ketcha*Lainey Mallin
Wright State University

In light of continual improvements in the radiochemical synthesis of 2-[18F]fluoroethyl azide ([18F]FEA), "click labeling" of alkynyl substituted targeting agents via a 18F-linked 1,2,3-triazole appendage is becoming a method of choice for positron emission tomography (PET) imaging purposes. The Proxy-PET concept takes the prospective view that since the fluoroethyl triazole appendage must be present in eventual PET imaging agents, building blocks incorporating a "cold-version" of this requisite feature might be prepared and utilized early on in the library synthesis.  With such a cold reporter group present in the initial binding assays, it is readily seen that an optimal targeting agent, once discovered, represents the actual PET imaging agent when prepared with an 18F-reporter.

Renata Mitton,
Tuning the Physical Properties of Poly(arylene ether)s Prepared from 3,5-Difluorobenzenesulfonamides

Renata Mitton and Eric FossumRenata Mitton
Wright State University, Department of Chemistry, 3640 Colonel Glenn Hwy, Dayton, Ohio 45435

A series of functionalized poly(arylene ether)s, PAEs, based on 3,5-difluorobenzene sulfonamides with varying groups on the sulfonamide moiety were investigated. The main goal of the project was to tune the thermal and, potentially, electronic properties of the PAEs by altering the organic groups present on the sulfonamide nitrogen atom, including combinations of alkyl, allyl, aryl, and benzyl moieties. Furthermore, the benzyl and aryl groups provide sites for the introduction of aryl bromides and iodides, which can undergo further modification via post polymerization modification chemistry.

Using 3,5-difluorobenzenesulfonyl chloride as a starting material, N-phenyl-N-R-3,5-difluorobenzene sulfonamides were prepared, followed by conversion to the corresponding PAEs by reaction of 3,5-difluorobenzene sulfonamides with bisphenol A.

The polymers were characterized by size exclusion chromatography, NMR spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The polymers displayed moderate thermal stability in air, glass transition temperatures depending on the R group.

Mitton 1.jpg

Kevin A. O'Neil,
A study of the adsorption behavior of silver nanoparticles at corundum interfaces using Inductively-Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Raman Spectroscopy

Kevin A O’Neil, Seth W. Brittle, Jennifer M. Purvis, Steven R. Higgins, Ioana E. Pavel Sizemore.Kevin O'Neil
Department of Chemistry, Wright State University

Due to the increased use of nanomaterials in consumer products, there is a growing need to monitor their release into the environment. Silver nanoparticles (AgNPs) are the most used nanomaterials in consumer products (over 23%) and have also received increased attention in other research and industrial areas. To monitor silver release in the environment, it is important to study the constituents of soils as they have contact with groundwater systems. As a large portion of soils, minerals are able to affect the mobility and availability within geochemical and aquatic systems. However, little is known about the interaction of AgNPs with minerals. To investigate these aspects, mineral particles (corundum, α-Al2O3, as a mineral model, 1.0 x 104 mg L-1, 149 nm in diameter) were exposed to Creighton AgNPs (~15 μg mL-1, ~10 nm in average diameter), and were characterized in the presence of an ionic strength adjuster (0.005 M of NaNO3). Surface complexation and percent adsorption of AgNPs to corundum were examined over a pH ranging from 6 to 9 and at different incubation times (from 5 min to 18 hrs) by Raman spectroscopy and inductively coupled plasma optical emission spectroscopy (ICP-OES), respectively. ICP-OES revealed AgNP-adsorption behavior when the pH was changed from 9 to 6, and AgNP-desorption behavior when the pH was increased from 6 to 9. The hysteresis effect noticed during the cyclical titration of the samples is probably due to the pH-dependent electrostatic interactions of the mineral surfaces with the colloidal AgNPs. Kinetic studies indicate an increase in the % AgNP adsorbed with time and the establishment of adsorption equilibrium after 3 hrs or more depending on pH. Preliminary Raman data suggest the formation of a silver oxide layer, which may be responsible for the kinetic behavior revealed by ICP-OES.

Sesha L. A. Paluri,
Surface charge, concentration and time dependent accumulation of silver nanoparticles in Vero 76 cells by ICP-OES

Sesha L. A. Paluria,b, Nhi Lama, Ioana E. P. Sizemorea,bSesha L. A. Paluri
a)  Department of Chemistry, Wright State University, Dayton, OH 45435-0001
b) Biomedical Sciences Ph.D. Program, Wright State University, Dayton, OH 45435

Silver nanoparticles (AgNPs), beside their multifaceted applications, were also shown to exert bimolecular perturbations following the cellular uptake. However, there is insufficient information on the actual concentrations of AgNPs that accumulate in cells. The main goal of the current study is to employ inductively coupled plasma optical emission spectroscopy (ICP-OES) to quantify total Ag accumulated in cellular and media portions of vero 76 cells  with respect to the surface charge (AgNPs+ and AgNPs-), concentration (0-300 µg mL-1) and exposure time (0-48 hr) of AgNPs. Laboratory-synthesized AgNPs were processed via tangential flow filtration (TFF) and characterized prior to treating cells. Spherical (~10 nm), moderately distributed colloidal AgNPs were utilized in this study. Results indicated that cellular accumulation of AgNPs was only ~10-15% of the treated concentrations while an order of magnitude higher accumulations were detected in culture media. At 300 µg mL-1, the cellular portions of AgNPs+ accumulated an order of magnitude higher Ag than AgNPs-. In addition to establishing ICP-OES for the quantification of total Ag in cells, this study suggests that it is important to characterize AgNPs and understand nano-media interactions prior to reporting lethal concentrations of AgNPs in toxicological studies.

Joel Schmitz,
Toward High Temperature Elastomers Based on Poly(arylene ether)s Derived from 3,5-difluorobenzene sulfonamides

Joel Schmitz, Marina Andrejevic, and Eric FossumJoel Schmitz
Department of Chemistry, Wright State University, Dayton, OH

Due to being excellent activators, sulfonamide groups were used to synthesize poly arylene ethers (PAEs) through meta-activated nucleophilic aromatic substitution (NAS). A series of N-alkyl-N-phenyl-3,5-difluorobenzene sulfonamides was synthesized, with alkyl groups ranging from methyl to dodecyl, along with N-allyl-N-phenyl-3,5-dilfluorobenzene sulfonamide.  These sulfonamides were then polymerized with bisphenol-A and the molecular weights of the polymers were determined using gel permeation chromatography (GPC). Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to determine the glass transition temperatures (T­g) of the polymers. Tg values were inversely proportional to the alkyl length chain of the polymer with the methyl version possessing a Tg of 122 °C while the dodecyl group exhibited a Tg of only 46 °C. Introduction of the allyl group provides potential access to “post” polymerization modification reactions through thiol-ene chemistry as well as a site for cross-linking to afford elastomers.

Schmitz-1.jpg

2014

Undergraduate Student Presenters

Bram Spierenburg,
Synthesis of a Haplomyrtin Precursor from a TIPS Protected Intermediate

Bram Spierenburg,* William S. Barrow and and William A. Feld
Department of Chemistry, Wright State University

Previous synthetic efforts directed at Haplomyrtin focused on the use of a benzyl protective function in the preparation of an intermediate 2-phenylbenzo-furan. The use of a TIPS protective group affords a distinct advantage in this preparation. Thus, the reaction of 6-bromovanillin with triisopropylsilylchloride produces 2-bromo-4-triisopropylsilyoxy-5-methoxybenzaldehyde. Protection of the benzaldehyde function as the cyclic ethylene ketal is followed by a lithium halogen exchange reaction and a subsequent reaction of the lithium intermediate with piperonal to produce a non-isolatable alcohol. Immediate reaction of the alcohol with an acid catalyst in the presence of dimethyl acetylenedicarboxylate (DMAD) produces the Diels-Alder product dimethyl 1-(1,3-benzodioxol-5-yl)-4-hydroxy-6-methoxy-7-triisopropylsilyloxynaphthalene-2,3-dicarboxylate, a Haplomyrtin precursor.

Spierenburg poster structure.jpg

 

Graduate Student Presenter

Kevin M. Dorney,
A surface-enhanced Raman spectroscopy (SERS)-based nano-sensing study of the intracellular partitioning of chelerythrine, a potential anticancer therapeutic, in lens epithelial cell cultures

Kevin M. Dorneya, Ioana E. P. Sizemorea, Tariq Alqathanib,c, Norma C. Adragnab,c, and Peter K. Laufb,c,d
Departments of aChemistry, bPharmacology & Toxicology, cCell Biophysics Group, and dPathology, Wright State University, Dayton, OH, USA, 45435

Quaternary benzophenanthridine alkaloids (QBAs) have been utilized for centuries in a variety of medicinal treatments and have gained recent interest due to their potential use as anticancer therapeutics. Chelerythrine (CET), a naturally occurring QBA, has received much attention due to a well-documented ability to induce apoptosis in a variety of human cancer cell lines. Despite this enormous therapeutic potential, little is known of the intracellular fate of CET and much speculation surrounds this topic. In order to shed light on this issue, this study aims to track the distribution of CET within human lens epithelial cell (HLEC) cultures via surface-enhanced Raman spectroscopy (SERS). Thus, HLECs were incubated with 50 ?M of CET at 37 °C for a time period of 30 min. Cellular fractions containing cytosolic, plasma membrane, and whole cell constituents were obtained, incubated with Creighton colloidal silver nanoparticles, and subjected to SERS-based nano-sensing. The SERS analysis rapidly and efficiently detected CET in all extracts with minimal sample preparation. The total CET content was interpolated via a linear calibration function of the SERS intensity of the symmetric C-C-C stretching mode of the aromatic backbone occurring at 659 cm-1. Concentrations of free CET were then normalized for total protein content in each extract. CET was found to accumulate within the cell above passive equilibrium diffusion concentrations, 267 ?M versus 244 ?M as calculated assuming a Nernstian equilibrium, which suggests rapid transport as a cationic monomer. Moreover, the number of CET molecules per ?g of protein in the plasma membrane was found to be nearly three orders of magnitude higher than in the cytosol (1.01 x 1014 and 3.11 x 1011, respectively), suggesting a strong affinity for plasma membrane proteins. CET was also detected in a purified Na+/K+ ATPase extract, offering strong support of the recent hypothesis that CET may induce apoptosis via binding and subsequent inhibition of the NKA.

Marina Andrejevic,
Effect of Alkyl Chain Length on the Thermal Properties of
Poly(arylene ether)s Derived From N-Alkyl-N-Phenyl-3,5-Difluorobenzene sulfonamides

Marina Andrejevic and Eric Fossum *
Department of Chemistry, Wright State University

Meta-activated nucleophilic aromatic substitution leads to poly(arylene ether)s, PAE, in which the activating group resides in a pendant position relative to the polymer backbone. The nitrogen atom in the strongly activating sulfonamide provides a point of chemical diversity that can be exploited to tailor the physical properties of the resulting polymers. Using N-phenyl-3,5-difluorobenzene sulfonamide group as the starting material a series of N-alkyl derivatives, with chain lengths of 3 to 12 carbon atoms, were prepared and characterized followed by conversion to the corresponding PAE.  The effect of alkyl chain length on the thermal stability and glass transition temperatures, Tg, values was determined.

marina andrejevic poster structure.jpg

 

Juraj Drzic,
Aryl Alkoxy Polyethers

Juraj Drzic and William A. Feld*
Department of Chemistry, Wright State University

    The ready availability of diphenol compounds 1 has lead to the synthesis of a series of building blocks for use in the preparation of unique monomers. The reaction of diphenols like aromatic bis(hydroxyl) compounds with 4-Toluene sulfonylchloride or  , -dibromoalkanes followed by deprotection leads to a series of AB monomers exemplified by 2. Similarly, the reaction of appropriate dibromides or ditosylates 2 with 4-fluoro-4'-hydroxybenzophenone leads to a series of unique PEEK related AB monomers illustrated by 3. Polymerization of these monomers can be conducted in NMP using K2CO2 as a base and toluene as an azeotroping agent.

Drzic 1.jpg Drzic 2.jpg

 Drzic 3.jpg

Kristy Wickman,
Novel Oxyalkylene Linked Polyimides

Kristy Wickman and William A. Feld
Department of Chemistry, Wright State University

Flexible oxyalkylene ether linkages within the polyimide backbone have been shown to decrease Tg but do not have a deleterious effect on thermal stability.  Several diamine compounds with oxyalkylene ether linkages were synthesized by the usual reaction of diols, hydroquinone bis(2-hydroxyethyl) ether, 2,2-bis[4-(2-hydroxyethoxy)phenyl]hexafluoropropane, and 4,4'-(9-fluorenylidene)bis(2-phenoxyethanol), with p-fluoronitrobenzene followed by chemical reduction. The diamines were converted to polyimides by using 4,4'-(hexafluoroisopropylidene)-diphthalic anhydride (6FDA) in a one-pot, amic-acid/imidazation procedure in m-cresol. The fully closed imides could be casted into transparent, creasable films and exhibited a 5% weight loss at >400° and appeared to exhibited a thermal transition ranging from 186-231° by DSC. Currently, another diamine synthesized from 4,4'-bis(2-hydroxyethoxy)-tetraphenyl methane, will be reacted with 6FDA to produce a polyimide which will provide comparison for thermal properties.

Jeremy Lear,
Synthesis of Main Chain Alkoxy Substituted DP-PPV and Application of HWE to DP-PPVs

Jeremy Lear and William Feld
Department of Chemistry, Wright State University

In the interest of the synthesis of polymers that have the potential to possess inherent light emitting properties (LEDs) the synthesis of a novel 1,4-bis(chloromethyl)benzene monomer, 5-benzyloxy-1,4-dichloromethyl-2,3-diphenyl benzene 1 was done.  Monomer 1 was polymerized via the Gilch polymerization method to yield, poly(5-benzyloxy-2,3-diphenyl phenylene vinylene) 2.  Polymer 2 was characterized by TGA, DSC, GPC, UV-Vis and fluorescence studies, and was found to have a Td5% of 267o, Mw/Mn of 7136 Da/6603 Da, an absorbance maximum at 406 nm and an emission maximum at 509 nm.
    The Horner-Wadsworth-Emmons variant of the Wittig was applied in the synthesis of poly(2,3-diphenyl-1,4-phenylenevinylene) (DP-PPV) 3 from 1,4-bis(diethoxyphosphorylmethyl)-2,3-diphenyl benzene 4, which was synthesized via the Michaelis-Abuzov reaction, and 2,3-diphenylterepthaldehyde 5.

Kaleb W. Cox,
Diversification by N-Alkylation of Benzylidene Oxindoles

Kyle J. Knisley, Kaleb W. Cox and Daniel M. Ketcha*
Department of Chemistry, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435

Given the central role of N-H arylidene oxindoles as kinase inhibitors, it is not surprising that the three points of diversity offered by N-alkylation of this scaffold are rarely exploited for drug discovery purposes. Having established the efficacy of benzylidene oxindoles as cell-death inhibitors with the same potency as Q-VD-OPh the goals of our research program have been to develop expedited methods for their preparation amenable to multi-parallel synthesis, especially as regards N-alkylation. An overarching stratagem of this design concept was to achieve these goals through a 'libraries from libraries' approach, wherein sub-libraries of precursor compounds could be prepared and screened for alternative applications before subjecting these compounds to further elaboration for subsequent screens in terms of cell-death inhibition or other applications.

cox1.jpg

The N-alkylation of benzylidene oxindoles is a reaction that has seen only limited usage and sometimes as the first step in a multi-step sequence (without isolation or characterization of the initial alkylated product).  We find that the N-alkylation of benzylidene oxindoles with benzylic or propargylic halides can be effected using either two bases; solid supported KF/alumina or the soluble liquid base DBU in ethanol.

Cox 2.jpg

Marjorie Markopoulos,
iRAMP:  A Chemical Hazard Assessment Platform
Managing laboratory chemical risk information for multiple audiences

Leah McEwen, Chemistry Librarian; and Ralph Stuart, Chemical Hygiene Officer, Cornell University
Secretaries, ACS Division of Chemical Information and ACS Division of Chemical Health and Safety
Presenter:  Marjorie Markopoulos, Biological and Chemical Hygiene Officer, Wright State University

In 2011, the US Chemical Safety Board released a report on safety in academic chemistry laboratories raising the concern for an organized risk assessment process that meets the needs of the research laboratory. In 2013, the American Chemical Society (ACS) Committee on Chemical Safety appointed a task force on Identifying and Evaluating Hazards in Research Laboratories.  The task force developed a report on several methods including the control banding approach, which assigns "Chemical Safety Levels" to laboratory operations to systematize these practices. These Chemical Safety Levels (CSLs) provide general guidelines for safety management practices; these practices can be further refined for application in specific laboratories and lab operations. A significant challenge identified in implementing this concept is the effort required to collect and organize the information necessary to complete a CSL assignment and detail how it applies to a specific laboratory process or setting.

Several other developments over the past five years are helping the chemistry community to meet this challenge, including significant improvements in electronic information handling, promulgation of hazard classification standards, and a paradigm for managing chemical hazards in an academic setting.  In order to bring these elements together to support use of the control banding approach in managing chemical risks, chemical researchers, chemical information professionals, and environmental health and safety professionals were brought together to vet the concept of a web-based chemical risk assessment engine.  This presentation will discuss the strategies of designing a convenient web-based interface that supports chemical safety planning by chemical researchers at the level of individual experiments, leveraging the Recognize, Assess, Manage, Plan (RAMP) chemical risk management model, the Globally Harmonized System of Classification and Labeling of Chemicals (GHS), and ChemSpider, the largest aggregation and management system of public domain electronic chemical information data.
 

2012

Undergraduate Student Presenters

Urmimala Chaudhuri
Electroanalysis of Chlorpromazine (CPZ) Utilizing Cetyltrimethylammoninm Bromide Carbon Paste Electrode (CTABCPE)

Urmimala Chaudhuri, Miyong Hughes, and Suzanne K. Lunsford, Ph.D.,
Department of Chemistry, Wright State University

Everyday surfactants have been widely employed in the field of analytical chemistry. This presentation will extend the use of the surfactant Cetyltrimethylammonium Bromide (CT AB). The CT AB will be the surfactant utilized to modify the carbon paste electrode in order to detect chlorpromazine (CPZ). CPZ is an antipsychotic drug used to block neurotransmitters in the brain in schizophrenic patients. CTAB was developed onto the carbon paste electrode to make a (CTABCPE). The CTABCPE reversible behavior was observed at a neutral pH in the detection of CPZ by utilizing cyclic voltammetry. In comparison to the bare carbon paste electrode, which did not exhibit reversible behavior electrochemically. Therefore, CT ABCPE proved to be more beneficial due to its increased selectivity and stability.

Andria Fortney
Tailoring the Solubility and Thermal Characteristics of Poly( ether ether ketone)s

Andria Fortney and Eric Fossum
Department of Chemistry, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435

Poly( ether ether ketone)s (PEEK) have high thermal stability and chemical resistivity due to their semi-crystalline character. However, they are also highly insoluble in aprotic solvents and therefore difficult to process. PEEK incorporates 4,4'-difluorobenzophenone, 1, in the backbone of the polymer chain. The use of its geometic isomer 3,5-difluorobenzophenone, 2, as a comonomer in the polymer's formation has been investigated. By varying the molar ratios of (1:2) coupled with the use of oligomeric monomers 4,4' - bis (4-hydroxyphenoxy) benzophenone, 3, and 3,5-Bis-(4-hydroxyphenoxy)benzophenone, 4, PEEK analogs have been developed that have the same chemical composition of PEEK but with varying structure-property relationships. The solubility and thermal characteristics of the resulting polymers meta-PEEK, 5, and PEEKx-co-m-PEEKx, 6 and 7(a-e), were dramatically influenced by varying the molar ratio of (1:2). At higher ratios of monomer 2, the meta PEEK, 5, 50:50, 6 and 73, and 75:25, 7b, polymers were completely amorphous and soluble in N-methylpryrrolidinone, while at lower ratios of monomer 2, the 80:20, 85:15 and 90:10, 7c, 7d and 7e polymers respectively, became semi-crystalline and their solubility decreased. TGA analysis indicated excellent thermal stability as the materials 5 % weight loss temperatures (T d5%) in excess of 410°C.

Jeremy Lear
Main Chain Alkoxy Substituted PPV

Jeremy Lear and William Feld
Department of Chemistry, Wright State University

In the interest of the synthesis of polymers that have the potential to possess inherent light emitting properties (LEDs) the synthesis of diethyl 5-benzyloxy-2,3-diphenylbenzenecarboxylate was conducted to produce an intermediate in the synthetic pathway for a novel 1,4-bis( chloromethyl)benzene monomer. The synthesis began with production of diethyl 5-([N-methyliminodiacetato-O,O' ,N]borane )-2,3-diphenylterephthalate, via a Diels-Alder reaction, using 2,5-dicarboethoxy-3,4-diphenylcyclopentadienone and ethynylboronic acid MIDA ester as starting reagents. The diester was de-boronated and oxidized to diethyl 5-hydroxy-2,3-diphenylterephthalate through a reaction with sodium carbonate (Na2C02) and 30% hydrogen peroxide (H202). Synthesis of diethyl5 benzyloxy-2,3-diphenylbenzenecarboxylate was achieved through a Williamson ether synthesis involving diethyI5-hydroxy-2,3-diphenylterephthalate and benzyl chloride. The products of each synthetic step were analyzed by lH NMR.

Kristy Wickman
1, 3-bis(1-adamantyl)imidazolium lithium phthalocyanine

Kristy Wickman and W. A. Feld
Department of Chemistry, Wright State University

DiIithium phthalocyanine is a dye and can be used as an electrolyte in solid-state batteries. Various tetra-alkyl ammonium cations have been exchanged with the free lithium ion in dilithium phthalocyanine in a metathesis reaction. Other compounds have been used in the metathesis reaction including 1, 3-bis( 1-adamantyl)imidazolium tetrafluoroborate. The synthesis of 1, 3-bis(1-adamantyl)imidazolium lithium phthalocyanine employed 1,3-bis(1-adamantyl)imidazolium tetrafluoroborate as a cationic salt in an exchange reaction with the free lithium ion in dilithium phthalocyanine. Earlier synthetic schemes gave yields of 55%. An improved synthetic sequence was developed that gave reproducible yields of 85%. Elemental and IH NMR analysis were used to establish the purity of the product. The new procedure appears to be scalable.

Graduate Student Presenters

Catherine B. Anders
A SERS and SEM-EDX Study of the Antiviral Mechanism of Creighton Silver Nanoparticles against Vaccinia Virus

Catherine B. Anders1, Adam C. Stahler1, Joshua D. Baker1, Tai Lam1, Tazeen Ahmed1, Virgil C. Solomon2, and Ioana E. Pavell Sizemore1,
Dept. of Chemistry, Wright State University, Dayton, Ohio

Silver nanoparticles (AgNPs) are well-recognized as antiviral agents but little is known about their mechanism of action. In this study, it was hypothesized that unfunctionalized, Creighton AgNPs of an average diameter of 11 nm will inhibit the viral replication of vaccinia virus (VV) through covalent bonding mainly to the external, entry fusion complex (EFC) proteins. The EFC is housed on the external membrane ofVV and contains 9-12 proteins having numerous cysteine groups, intramolecular disulfide bonds, aromatic moieties and myristic acids bound to the N-terminus of glycine residues. VV (1012 PFUs) was incubated at 37°C for one hour with Creighton AgNPs that were size selected (1-25 nm in diameter) and concentrated (1,000 ppm silver) using tangential flow ultrafiltration. After incubation, the sample was rinsed three times to remove any unbound AgNPs from the VV. The VV -AgNP sample was then deactivated with formaldehyde and fixed onto glass slides and stubs for surface-enhanced Raman spectroscopy (SERS) and scanning electron microscopy-energy dispersive X-Ray (SEM-EDX) analysis, respectively. SERS maps containing over 2,600 spectra were collected and processed using in-house written MatLab codes. Six endmember spectra were extracted from the hyperspectral data set using a multivariate statistical analysis method, namely vector component analysis (VCA). The SERS analysis of the six endmember spectra indicated an interaction trend similar to that reported in literature by other SERS studies on proteins exposed to AgNPs: carboxylic groups > peptide bond interactions (amide peaks) > aromatic AAs > thiol groups> small side chains. Additionally, the SEM electron backscatter images and the EDX spectrum of the VV-AgNP sample revealed the presence of silver and further supported the direct interaction between AgNPs and VV. These interactions confirmed the proposed hypothesis and suggest that these covalent bonding interactions might disrupt the VV ability to complete the entry/fusion steps of the viral replication cycle.

Joshua D. Baker 
Green size-selection and concentration of unfunctionalized silver nanoparticles for SERS-based sensing applications

Joshua D. Baker, Catherine B. Anders, Adam C. Stahler, Austin Williams, and Ioana E. P. Sizemore
Department of Chemistry, Wright State University, Dayton, OH 45435

Silver nanoparticles (AgNPs) are widely used in consumer products, water disinfectants, therapeutics, biomedical devices and surface-enhanced Raman spectroscopy (SERS)-based sensing. The size and aggregation state of AgNPs significantly affect these applications. Limitations arise from the toxicity of reagents, high costs or reduced efficiency of the AgNP synthesis, and isolation methods (e.g., centrifugation, size-dependent solubility, etc.). Tangential flow ultrafiltration (TFU) is a commonly used recirculation method that isolates proteins or cells according to their weight through a series of hollow fiber membranes with pore size ranging from 10 kD to 1,000 kD. In this study, TFU was modified tosize-select and significantly concentrate a large volume of polydisperse colloidal AgNPs. The well-established Creighton method was utilized to synthesize unfuctionalized AgNPs (4 L, 14.7 ug mL-1) by the reduction of AgN03 with NaBH4• A three-step TFU was utilized where a 50 nm module was used to remove AgNPs and AgNP-aggregates greater than 50 nm in diameter followed by two 30 kD modules to concentrate the AgNPs. TFU may be considered a "green" method as it neither damages the sample nor requires additional solvent to eliminate toxic excess reagents and byproducts. The AgNPs were characterized using TEM, UVVis absorption spectrophotometry, Raman spectroscopy and ICP-OES. The fmal 30 kD AgNP retentate was highly concentrated (2 mL, 6.04x 102 ug mL-1) yet minimally aggregated and homogeneous (1-20 nm diameter). These highly concentrated AgNPs were found to greatly enhance the SERS-based sensing capabilities of the Creighton colloid. SERS events were observed at 10-9 M of R6G as compared to the original AgNP colloid detection limit of 10-6 M of R6G. This was attributed to an increased number of SERS hot spots available for a target molecule within the minimal focal volume.

Daniel Brown
Halogenations of Aryl Substituted Sydnones

Daniel Brown, Jennifer Benson, Ashley Clark, Kyle Liddy, Jeffrey Morehead, Kyle Oxman
Department of Chemistry, Wright State University, Dayton, OH 45435

Recently, a novel avenue to the iodination of sydnones at the 4-position has been developed using Niodosuccinimide in acetic acid (cf. 1 to 2). The scope of this concept will be enumerated using various activated and deactivated arylsydnones, and extended by means of other halogenating reagents, such as N-chlorosuccinimide and N-bromosuccinimide.

Jessica M. Dagher
Transport of Engineered Silver Nanoparticles through Saturated Porous Media

Jessica M. Dagher1, Sushil R. Kanel2, Allie Meyerhoefer1, Mark N. Goltz2, and Ioana E. P. Sizemore1
1Department of Chemistry, Wright State University,
2Department of Systems and Engineering Management, Air Force Institute of Technology
Dayton, Ohio

Silver nanoparticles (AgNPs) have been increasingly applied in various nanotechnology areas due to their unique optical and antimicrobial properties. With elevated release of AgNPs into the environment, their interaction with groundwater and soil needs to be examined. This study examines the transport of colloidal AgNPs of various diameters (1-100 nm size range) through water saturated porous media at low flow rates (1 mL min-I), fixed pH (~8) and ionic strength (0.01 mM KCl). The colloidal AgNPs were synthesized using a Creighton method and were size-selected using a tangential flow ultrafiltration approach. The physicochemical properties of AgNPs (purity, shelf lifetime, average size, size distribution, aggregation state, surface plasmon resonance, and surface charge) were then determined via Raman spectroscopy, ultraviolet-visible absorption spectroscopy, transmission electron microscopy, and Zeta potential measurements. AgNPs (15.3 ppm) and a conservative tracer (Cr ions) were injected in upward direction through a one-dimensional column (5 cm depth, 2.5 cm diameter) that was pre-packed with saturated glass beads. Effluent was collected at two minute intervals and analyzed. AgNP samples were chemically digested, quantitatively diluted and acidified. The concentration of silver in the colloids was determined using flame atomic absorption spectroscopy and inductively coupled plasma optical emission spectroscopy. Breakthrough graphs were created by plotting the normalized concentration of AgNPs versus normalized time. The transport of AgNPs of 1-100 nm in diameter showed no retardation with respect to the tracer at 1 mL min-I. Some AgNPs were captured within the media pores. Future experiments will be performed to study the transport of colloidal AgNPs in heterogeneous porous media (sand and real soil).

Mark R. Duffy
Cyclopentadienone Dimers

Mark R. Duffy and Dr. W. A. Feld
Department of Chemistry, Wright State University

The exposure of solid, red 2,5-dicarboethoxy-3,4-di (4-methylphenyl)cyclopentadienone to visible light results in the formation of a colorless "dimer". The cyclopentadienone is synthesized from 4,4'dimethylbenzil and diethyl I,3-acetonedicarboxylate. The structure of the "dimer" includes a central eight membered ring with two bridging carbonyls that shows interesting characteristics in the solid and solution state. It appears to be photochemically unstable in solution and undergoes transesterification on recrystallization from I-propanol. Further research is in progress on this ring system to understand what manipulations it can undergo and how these manipulations affect its reactivity.

Dennis Lennaerts
Dissolution kinetics of gypsum (010) surfaces

Dennis Lennaertsa, Matthieu Martinb, Elliott R. Brownb and Steven R. Higginsa
aDepartment of Chemistry, Wright State University, Dayton, OH
bDepartment of Physics, Wright State University, Dayton, OH

To gain a better fundamental understanding of crystal dissolution and formation, it is essential to obtain surface-specific information on how various properties are influenced by the saturation state of the solution, Q better fundamental understanding of crystal he dissolution kinetics of the (010) surface of gypsum were investigated using batch chemical reaction vessels and polished mineral specimens. In this work, natural gypsum samples were cleaved on the (010) surface, encapsulated in epoxy and polished. Subsequently, the samples were exposed to undersaturated solutions (edna0.459 - 0.783) in free drift experiments. During experiments, aliquots (200 µL) of the solution were taken periodically and analyzed for Ca concentration by flame atomic absorption spectroscopy. After dissolution runs, the gypsum surface morphology was characterized by atomic force microscopy. Additionally, surface profiles were taken with a profilometer, providing a means for calculating the mean dissolution rate in comparison to rates calculated from the Ca concentration data. The results indicate a relation between the saturation state of the solution and the dissolution rate. No relation was found between the stir rate and the dissolution rate, making it more likely that the dissolution reaction is controlled by surface morphology and other surface specific characteristics instead of diffusion of calcium from the crystal-solution interface.

Ryan Oostendorp
Bis( alkoxypbenyl)cyclopentadienones

Ryan Oostendorp and W.A. Feld
Department of Chemistry, Wright State University

Poly(p-phenylenevinylene) (PPV) has been used in a variety of applications particularly in electronic devices such as LED displays and related semiconducting systems. Cyclopentadienones have been employed as PPV precursors specifically as carriers of various electron-donating and electron-withdrawing substituents. Alkoxy substituted PPV precursor cyclopentadienones are rare. Dimethoxybenzil could serve as a basis for synthesizing dialkoxysubstituted cyclopentadienones however, its solubility is low in sovents required for cyclopentadiene synthesis. Thus, 4,4' -dimethoxybenzil was demethylated and alkylated with appropriate solubilizing groups. The reactions and characterization of alkylated benzyl will be presented

Adam Stahler
Improving the SERS-based sensing capabilities of Silver nanorod thin films: A SERS study on the Effects of Fabrication Temperature

Adam Stahlera , Piyush Shahb, Andrew Saranganb, and Ioana Pavel Sizemorea
aDepartment of Chemistry, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45434
bElectro-optics Graduate Program, University of Dayton, 300 College Park, Dayton, OH 45469

The fabrication of silver nanorods (AgNRs) through oblique angle deposition (OAD) remedies many concerns of traditional SERS substrate fabrication due to OAD being relatively inexpensive, fast, and fine-tunable, allowing for the fabrication of highly reproducible uniform SERS substrates. SEM images revealed a greater surface area for AgNRs fabricated at 100 K (2.72xl0-12m2/f.A,m2) than AgNRs produced at 300 K (1.70xl0-a m2/um2). Therefore, it was hypothesized that the SERS-based sensing capabilities would be significantly improved for 100 K fabricated AgNRs over those produced at 300 K. AgNRs were incubated in solutions of Rhodamine 6G (R6G, 10-6M, 10-7 M, and 10-8 M) and micro-Raman maps were collected. For all AgNRs fabricated at 100 K Raman map analyses revealed greater area exhibiting significantly increased signal (l.5 fold at 10-6 M, 3.7 fold at 10-7 M, and 6.5 fold at 10-8 M). Significant morphological differences in AgNR structure pre and post-incubation explain the significant enhancement in SERS signal observed.

Courtney Sutherland
Poly(arylene ether)s prepared from functionalized 3,5-difluorotriphenylphosphine oxide

Courtney Sutherland and Eric Fossum
Department of Chemistry, Wright State University

The 3,5-difluorotriphenylphosphine oxide monomer is the geometric isomer of 4,4-difluorotriphenyl phosphine oxide, allowing for polymerization via nucleophilic aromatic substitution, NAS. This provides an avenue for the introduction of a high density of pendant functional groups for modification of the 3,5-difluorotriphenyl phosphine oxide based polymers. This particular project is focused on the "pre" functionalization of 3,5-difluorotriphenyl phosphine oxide, as well as the "post" functionalization of the polymer. We set out with the goal of discovering a facile method for introducing a variety of functional groups to P AEs synthesized from the iodinated derivative of 3,5-difluorotriphenyl phosphine oxide, (3,5-DiFTPO). Model reactions were performed at 150°C, 160 °C, and 170°C, using the iodinated monomer, 1, with t-butyl phenol to verify that the carbon-iodine bonds are able to withstand the conditions ofNAS, 2a-c. Polymerization of 1 was carried out at the same temperatures. The iodinated polymers, 3a-c, allowed for the "post" functionalization of the polymers, using a variety of boronic acids for Suzuki coupling, 4-6. Thermal data, Tg and Td5%, was acquired to verify that the functionalization of the systems allows for the tailoring of polymeric properties.

Triet Truong
New primers reveal the presence of a duplicate histone H3 in the marine turtle leech Ozobranchus branchiatus

Triet Truong and Audrey E. McGowin, Ph.D. Department of Chemistry
Philip Lavretsky and Jeffrey L Peters, PhD Department of Biological Sciences

Marine leeches, specific to sea turtles, have been implicated as potential vector organisms in the spread of fibropapillomatosis (FP), a pandemic neoplastic disease with green turtles (Chelonia mydas) having the highest affliction rate. Polymerase chain reaction identified two independent, seemingly functional histone H3 loci for marine turtle leeches Ozobranchus branchiatus collected from C. mydas in Florida and Hawaii. Primers were developed to amplify each product separately. These novel markers will be useful in identifying ectoparasites in FP research, evaluating other histone variants, and chromatin dynamics regulation studies.

2011

Undergraduate Student Presenters

Zach S. Arnold
Comparative cytotoxicity study of ionic silver and silver nanoparticles using an MTT bioassay

Zach S. Arnolda, Alice Changa, Nora E. Hunterb, Marjorie M. Markopoulosc, Sesha Lakshmi A. Palurid, John C. Trefryc, Dawn P. Wooleyc, and Ioana E. Pavela-d
aDepartment of Chemistry, Wright State University, Dayton, Ohio
bEnvironmental Sciences Ph.D. Program, Wright State University, Dayton, Ohio
cBiomedical Sciences Ph.D. Program, Wright State University, Dayton, Ohio
dDepartment of Pharmacology and Toxicology, Wright State University, Dayton, Ohio

The development and deployment of nanomaterials for consumer applications is underway. In fact, 54% of the nanomaterials in commercial use contain silver due to its antimicrobial and antiviral properties. Yet, little is known about the cytotoxicity of silver nanomaterials, in particular silver nanoparticles (AgNPs). In this study, non-ionic AgNPs were synthesized, characterized, and size-selected for use in comparative toxicological studies. Colloidal AgNPs were produced using a modified Creighton method by the reduction of silver nitrate with sodium borohydride. The physicochemical properties of AgNPs were characterized to confirm the size and shape distribution (TEM, UV-Vis absorption spectrophotometry), surface functionalization and charge (reaction mechanism), aggregation state (TEM), concentration (flame atomic absorption spectrophotometry), and purity (Raman spectroscopy). The U.S. Environmental Protection Agency and other organizations have recently established these parameters as being critical for the comparison between various cytotoxicity studies. Tangential flow ultrafiltration was employed to size-select AgNPs (20 nm diameter and smaller) and to concentrate them (larger than 10-fold) in a small volume of water with minimal aggregation for cellular dosage. Monkey kidney cells (Vero 76) and murine long osteocytic bone cells (MLO-Y4) were exposed to varying concentrations of ionic silver (Ag+) and nonionic AgNPs ranging from 0 to 512 ppm. MTT, an in vitro bioassay, was used to measure the cell metabolic function and to determine the median lethal dose (LD50) of silver ionic and nonionic AgNPs. LD50 of silver ionic was calculated at 29 ppm (VERO 76) and 26 ppm (MLO-Y4) using the Kärber and the Reed-Muench formula. The LD50 values obtained using the two methods were found to agree very well with each other. Preliminary results obtained for the Vero 76 and MLO-Y4 cells indicated AgNPs as being at least 10-fold less cytotoxic than the ionic silver (LD50 in the 64-512 ppm range).

Fadwa Constandinidis
POLY(ARYLENE ETHER)S DERIVED FROM 3,5-DIFLUOROBENZOTRIFLUORIDE

Fadwa Constandinidis and Eric Fossum, Ph.D.
Wright State University, Department of Chemistry, Dayton, Ohio

The characterization and polymerization behavior of a B2 monomer, 3,5-difluorobenzotrifluoride, 1, designed for nucleophilic aromatic substitution, NAS, reactions have been studied. As determined by a combination of NMR spectroscopy and model reactions, the electrophilic sites present at the 3 and 5 positions in monomer 1 were sufficiently activated by the presence of the trifluoromethyl group, located in the meta position, to allow displacement reactions to occur under relatively mild conditions. Reaction with a variety of bis-phenolates provided the corresponding poly(arylene ether)s, PAEs, which carried a pendant trifluoromethyl group. Unfortunately, the polymerization process was also accompanied by a competing cyclization process, which led to cylic oligomers. In order to limit the formation of oligomers, the initial concentration of A2 monomer was varied from 80-100%. GPC traces indicated a clear increase in molecular weight and a reduction of cyclic species when the initial A2 concentration was reduced. The resulting materials were completely amorphous as indicated by the presence of only a glass transition temperature in their DSC traces. They were soluble in a wide variety of organic solvents. The 5% decomposition temperatures obtained from thermogravimetic analysis indicated that they possessed excellent thermal stability.

Fadwa Constandindis poster chemical reaction.jpg

Andria Fortney
TAILORING THE SOLUBILITY AND THERMAL CHARACTERISTICS OF POLY(ETHER ETHER KETONE)S

Andria Fortney, and Eric Fossum, Ph.D. Wright State University,
Dept. of Chemistry, Dayton, Ohio

The solubility and thermal properties of poly(ether ether ketone) (PEEK) have been modified by incorporating various ratios of a comonomer, 3,5-difluorobenzophenone. 1. Since 1 is simply the geometric isomer of 4,4’-difluorobenzophenone, 2, which is traditionally utilized to synthesize PEEK, the resulting polymers have the same chemical composition, allowing for very accurate structure-property relationships to be determined. In addition, the use of monomer 1 affords PEEK systems that carry pendant benzoyl groups, which provide a versatile site for the introduction of functional groups. The thermal properties were investigated by a combination of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The ratio of monomer 2 to monomer 1 had a dramatic influence on the thermal properties and solubility characteristics of PEEK. At lower ratios, 50:50 and 75:25, the PEEK derivatives were completely amorphous and soluble in N-methylpryrrolidinone (NMP), while at higher ratios, 80:20, 85:15, and 90:10, the materials became semi-crystalline and their solubility in NMP decreased significantly. TGA analysis indicated excellent thermal stability as all of the materials 5 % weight loss temperatures (Td5%) in excess of 450°C.

Andria Fortney poster chemical reaction.gif

Ashley Hoang
DETERMINATION OF THE KINETIC PARAMETERS OF BB’B’ MONOMERS UTILIZED TO PREPARE HYPERBRANCHED POLY(ARYLENE ETHER)S

Ashley Hoang, Shravanthi Raghavapuram, and Eric Fossum, Ph.D.
Wright State University, Dept. of Chemistry, Dayton, Ohio

The degree of branching in hyperbranched poly(arylene ether)s prepared from 3,5,4’-trifluorodiphenyl sulfone, 1, or 3,5,4’-trifluorobenzophenone, 2, can be tailored via reaction temperature. 13C and 19F NMR spectroscopic analysis of 1 and 2 indicated that the 4’- site was the most reactive and that displacement of the first meta fluorine resulted in a considerable decrease in the reactivity of the second. To better understand and control the overall polymerization process it is crucial to determine the activation energy of each reactive site in the BB’B” monomers. Thus, a series of kinetic studies were performed, employing 2 equivalents of m-cresol, as the nucleophile. Initial kinetic studies were carried out on the corresponding BB’ monomer, 3,5-difluorodiphenyl sulfone. Reaction temperatures of 75 °C, 100 °C, 125 °C, and 150 °C were utilized and the aliquots removed from the reaction mixture were analyzed via a combination of GC/MS and NMR spectroscopy.

Ashley Huang-poster-chemical reaction.gif

Miyong Hughes
SIMULTANEOUS DETERMINATION OF CATECHOL AND ASCORBIC ACID WITH CTAB MODIFIED CARBON PASTE ELECTRODE

Miyong Hughes and Suzanne K. Lunsford, Ph.D.
Wright State University, Dept. of Chemistry, Dayton, Ohio

Catechol is a common neurotransmitter involved in neurological diseases such as Parkinson’s, Alzheimer’s disease, and Schizoprenia. Selective determination of catechol in the presence of ascorbic acid (AA) has gained considerable attention over the years. The concentration of catechol and AA and other neurotransmitters in biological samples vary from species to species, in a wide range, from 10-7 M to 10-2 M. Hence, selectivity and sensitivity are important in the development of any procedure for the determination of catechol in the presence of common interferents such as AA. Several electrochemical techniques and electrode materials have been explored for the analytical determination of the neurotransmitters. Electrochemical analysis of unmodified electrodes such as glassy carbon (bare carbon paste electrodes) has the disadvantage of a lack of selectivity due to overlapping oxidation potentials of catechol and AA. This poster presentation will discuss the use of a cation surfactant Cetyltrimethylammonium Bromide (CTAB) modified carbon paste electrode. This hand built CTAB carbon paste electrode was fabricated and applied to simultaneous determination of catechol and AA. The modified CTAB electrode resolved the overlapped voltammetric responses of catechol and AA without the need of prior separation techniques which will be illustrated

Allie J. Meyerhoefer
ESTIMATING THE ANALYTICAL AND SURFACE ENHANCEMENT FACTORS IN SERS: A NOVEL PHYSICAL CHEMISTRY AND NANOTECHNOLOGY LABORATORY EXPERIMENT

Joshua D. Baker, Khadijeh S. Alnajjar, Jennifer L. Monahan, Adam C. Stahler, Nora E. Hunter, Kent M. Weaver , Allie J. Meyerhoefer, David A. Dolson, and Ioana E. Pavel, Ph.D.
Wright State University, Dept. of Chemistry, Dayton, Oh

Surface-enhanced Raman spectroscopy (SERS) is an embodiment of Raman spectroscopy that has all molecular fingerprint capabilities of Raman and extremely high sensitivity. Theory predicted and experiments confirmed that exceptionally large Raman cross-section increases (i.e., single-molecule detection events) are associated with targeted molecules located in the nano–sized interstitial sites of aggregates of interacting silver nanoparticles (AgNPs). Recently, a novel laboratory experiment was successfully implemented for undergraduate and graduate students in physical chemistry and nanotechnology classes. The main scientific goal of this experiment was to demonstrate the SERS-based sensing capabilities of colloidal AgNPs by estimating the analytical (AEF) and surface (SEF) enhancement factors. AEF and SEF are the most important values for characterizing the SERS effect. Additionally, most SERS-based cutting-edge applications (e.g., cellular imaging, protein and DNA detection, quality control in both chemical and pharmaceutical industries, etc.) require an accurate determination of the magnitude of the signal enhancement. To achieve this, students synthesized a Creighton colloid and characterized its optical properties by UV-VIS absorption spectrophotometry. A rhodamine 6G fluorescent dye (R6G) was added to the colloidal AgNPs to determine the AgNP enhancement efficiency. Raman, SERS and fluorescence measurements were then performed to estimate the AEF (7.4 × 104) and SEF (5.2 × 101) values. Although these factors do not correspond to single-molecule detection events (maximum enhancement of 105 and 7 × 109 for colloids), the R6G concentration (1.0 × 10-6 M) was three orders of magnitude less than in previous laboratory experiments and facilitated the rapid acquisition of SERS spectra with very good signal–to–noise ratio. This laboratory experiment successfully introduced students to the fundamentals of SERS spectroscopy and to concepts related to light scattering, surface chemistry and resonance effects. Furthermore, students acquired new instrumental and nanotechnology–related skills that will benefit them in technologically-demanding careers.

Sarah Slate
ELECTROANALYSIS OF NADH AND L-DOPA USING A CONDUCTING POLYMER CARBON MODIFIED ELECTRODE

Urmi Chaudhuri, Sarah Slate, and Suzanne K. Lunsford, Ph.D.
Wright State University, Dept. of Chemistry, Dayton, Oh

The electrochemical oxidation of dihydronicotinamide adenine dinucelotide (NADH) in aqueous solution has been an increase interest since it plays a role in the generation of ATP, the body’s energy currency, and has been found to be deficient in several age related degenerative diseases. Therefore, NADH/NAD+ redox enzymes are of extreme importance in biological systems as well as the common neurotransmitter such as L-DOPA (3,4-dihydroxyphenylalanine). The NADH and L-DOPA have been found to be beneficial for patients suffering from Parkinson’s disease, Alzheimer’s disease and depression. Over the past few decades, conducting polymers play a critical role in the development of biosensors. These chemically modified polymer electrodes was developed to meet the needs for controlling the reactivity, selectivity and sensitivity of the electrode reactions. The main use for such conducting polymers as poly(2,2-bithiophene) implemented on modified electrodes is centered on the optimization of the electrocatalytic processes and electrocatalysis. The employment of cyclic voltammetry (CV) has been used across many fields of chemistry to study redox states and will be carried out to analyze the redox reactions of NADH and L-DOPA in this study at pH values around neutral. CV enables a wide range to be rapidly scanned for reducible or oxidizable species. We will discuss and present the voltammetric studies of NADH and L-DOPA at a poly(2,2-bithiophene) modified carbon electrode.

Triet Truong
DNA BARCODING OF SEA TURTLE LEECHES (OZOBRANCHUS SPP.) IN FLORIDA COASTAL WATERS

Triet Truong and Audrey E. McGowin, Ph.D.
Department of Chemistry, Wright State University, Dayton, Ohio

The etiological agent of Fibropapillomatosis (FP), a neoplastic disease originally identified only on green sea turtles (Chelonia mydas), is still unknown. Studies have shown an association between FP and the fibropapilloma-associated turtle herpesvirus (FPTHV), but not all turtles with FPTHV develop FP. Recently, high viral loads of FPTHV were detected in marine turtle leeches (Ozobranchus spp.) from a green sea turtle, but the study failed to identify the species of marine leech. Leeches may transmit or activate FPTHV but are impossible to identify at all life stages using taxonomic practices. In this study, character-based DNA barcoding using mitochondrial cytochrome c oxidase I (COI) gene as a molecular marker was employed successfully to identify both species of Ozobranchus spp. (Ozobranchus branchiatus and Ozobranchus margoi) at all stages of development from eight different sites in Florida (Daytona Beach to Key West). Genetic sequences for O. branchiatus and O. margoi were submitted to the National Center for Biotechnology Information GenBank with O. branchiatus added as a new species to the database. The spread of FP to other species of turtles combined with the discovery of a new turtle host for the O. branchiatus leech suggests the vector organism involvement behind FP maybe species specific. However, further sampling and genetic analyses must be conducted in order to confirm whether the separate haplotypes identified for O. branchiatus on a loggerhead are indeed haplotypes of the same species and not the discovery of cryptic specimens.

Triet Truong
IDENTIFYING NEW HAPLOTYPES AND POTENTIAL CRYPTIC SPECIES FOR MARINE LEECHES (OZOBRANCHUS SPP.) FROM HAWAIIAN AND FLORIDA SEA TURTLES BASED ON MOLECULAR DATA

Triet Truonga and Audrey E. McGowin, Ph.D. ,a Philip Lavretsky,b and Jeffrey L. Peters, Ph.D.b
 Department of Chemistrya & Department of Biological Sciencesb, Wright State University, Dayton, Ohio

Character-based DNA barcoding using mitochondrial cytochrome c oxidase I (COI) gene as a molecular marker was employed to identify both species of Ozobranchus spp. (Ozobranchus branchiatus and Ozobranchus margoi) at all stages of development from different Florida and Hawaiian locations. The COI barcode for O. branchiatus reveals multiple fixed polymorphisms between specimens collected on C. mydas (green turtles) in Florida and Hawaii. Phylogenetic analysis of O.spp at other genes (18S rDNA, 28S rDNA, and Histone H3) is being used to establish whether O. branchiatus specimens from Hawaii and Florida are distinct species. Interestingly, the separate COI haplotypes identified for O. branchiatus on Florida green turtles share closer genetic similarities to O. branchiatus found on Hawaiian green turtles, raising the possibility the specimens found on a Florida Caretta caretta (loggerhead) might actually be a cryptic species or subspecies of O. branchiatus. Extensive molecular analysis at different loci will help elucidate whether the O. branchiatus leeches collected from a loggerhead are haplotypes of the same species or a cryptic species. New primers were developed to sequence the Histone H3. Prior to this study, only genetic data for the COI gene of Florida O. branchiatus was available in the National Center for Biotechnology Information (NCBI) Genbank. This is also the first study to sequence the nuclear ribosomal gene 28S rDNA and the nuclear protein coding-gene Histone H3 for O. margoi.

Graduate Student Presenters

Amanda Balaguer
METAL TRIFLATE CATALYSTS IN FRIEDEL-CRAFT ACYLATIONS OF SYDNONES

Amanda Balaguer, Ryan Selhorst, and Kenneth Turnbull, Ph.D.,
Wright State University, Dept. of Chemistry, Dayton, Ohio

In a comparative study, various homogeneous metal triflates have been used as catalysts in the acylation of 3-phenylsydnone with acetic anhydride. Reactions were performed initially under thermal conditions overnight and monitored by thin layer chromatography for completion. When optimal conditions were achieved, these predetermined parameters were employed for “scaled-up” reactions, with the modification that they were performed under microwave irradiation, which gave better yields of the acylated product in shorter amounts of time. Thermal reactions took overnight to react while microwave reactions took 30 minutes. Future work includes testing the efficiency of other metal triflate catalysts, expanding the study to different parent sydnones, and utilizing various other anhydrides. The scope and limitations of the present findings will be enumerated.

 

Amanda Balaguer chemical reaction.gif

       5-ALKOXY-1,4-DICARBOETHOXY-2,3-DIPHENYLBENZENES

Andrew M. Beauchamp
SYNTHESIS OF ALKYL ALKOXY AMMONIUM COMPOUNDS FOR USE IN EXCHANGE REACTIONS

Andrew M. Beauchamp, and William A. Feld, Ph.D. 
Department of Chemistry, Wright State University, Dayton, Ohio

Multiple alkyl alkoxy ammonium ionic liquids were synthesized by quaternization reactions with tris[2-(2-methoxyethoxy)ethyl]amine and alkyl halides. These compounds were used in cation exchange reactions with dilithium phthalocyanine. The ether functionalized cations were used in an effort to improve ion conductivity while reducing electronic conductivity by taking advantage of the characteristics used in current electrolytes such as polyethylene oxide. The products were found to be low melting solids that may have use in new electronics technology.

Jeffrey D. Fogle
RESTRICTED ROTATION IN ORTHO-FLUOROPHENYL SUBSTITUTED DERIVATIVES

Jeffrey D. Fogle and William A. Feld, Ph.D.
Department of Chemistry, Wright State University,Dayton, OHIO

Various 2,3-bis(2-fluorophenyl)benzene derivatives were synthesized with various R groups in the 1,4-position and hexyl substituent in the 5 postion. The various R groups include: CO2Et, CH2OH, CH2Cl, COOH and COCl. The 1H, 13C and 19F NMR spectra show the occurrence of “cis” and “trans” diastereomers due to the restricted rotation caused by the ortho-substituted fluorine. The asymmetric derivatives give rise to four enantiomers (two for cis and two for trans) which has signals visible in some spectra corresponding to all four isomers. The degree of restriction is shown to be affected by the R groups in the 1,4-position.

Jeff Fogle poster reaction products.gif

R = CO2Et, CH2OH, CH2Cl, COOH, COCl

Dennis Lennaerts
ADSORPTION AND DESORPTION OF BARIUM TO HEMATITE (µ-Fe2O3) IN ARTIFICIAL SEAWATER

Dennis Lennaerts and Steven R. Higgins, Ph.D.,
Wright State University, Department of Chemistry, Dayton, Ohio

Barite (BaSO4) is a widely studied mineral that forms in the ocean by precipitation. To correctly interpret the results of barite studies it is important to know how and where the precipitation takes place. One of the suggested ways is the adsorption of barium to iron oxides at shallow depth followed by sinking of the iron oxides and release of the barium at deeper depth (Sternberg et al. 2005). This adsorption/desorption is driven by the pH difference at different depths. This research focuses on the adsorption/desorption of barium to hematite (a-Fe2O3 in artificial seawater. The adsorption is studied at various pH levels to simulate the varying pH at depth in the ocean. The barium concentration in artificial seawater is measured with ICP-OES at various time intervals in order to calculate the kinetics of the adsorption. Experiments were conducted as a function of time, solution pH and initial Ba concentration in synthetic seawater and the results and interpretation of these investigations will be presented.

Rachel Sayers
5-ALKOXY-1,4-DICARBOETHOXY-2,3-DIPHENYLBENZENES

Rachel Sayers and William A. Feld, Ph.D.
Department of Chemistry, Wright State University,  Dayton, Ohio

A series of alkoxy, phenylated terephthlates has been synthesized as monomer precursors to the corresponding poly(phenylene vinylene)s (PPV). The hydroxy terephthalate was synthesized via 1) a Diels-Alder cycloaddition between an ethynyl boronic ester and a cyclopentadienone and 2) hydrolysis/oxidation of the boronate ester. The synthesis, characterization and subsequent manipulation of the unique terephthalate as PPV precursors will be presented.

Rachel Sayer Poster Reaction and Products.gif

Michael E. Smith
EFFECT OF CRYSTAL ORIENTATION ON THE DISSOLUTION KINETICS OF CALCITE SURFACES BY AN ATOMIC EMISSION SPECTROSCOPIC AND INTERFEROMETRIC APPROACH

Michael E. Smith,a Steven R. Higgins, Ph.D.,a and Kevin G. Knauss, Ph.D.b
aWright State University, Department of Chemistry, Columbus, OHIO
bLawrence Berkeley National Laboratory, Earth Sciences Division, Berkeley, CA

Geologic CO2 sequestration has emerged as a technology to reduce greenhouse gas emissions by injecting CO2 into subsurface mineral reservoirs consisting predominately of cementing carbonate minerals, e.g. calcite. However, geochemical reactions between subsurface minerals and CO2 containing fluids can potentially alter the porosity and permeability of subsurface minerals which can ultimately cause undesirable leakage of CO2 from sequestration reservoirs back to the atmosphere. In the present work, we’ve examined the effects of polished crystal-surface orientation and degree of solution undersaturation on the dissolution kinetics of calcite as a means of improving our understanding of fundamental reactions that may influence the efficacy of CO2 sequestration in geological formations. Surface orientations of interest included ~ 1 cm2 areas of both the (104) crystallographic plane of natural calcite specimens, consisting of flat terraces with few steps, as well as fully kinked surfaces created by sectioning approximately parallel to the (001) plane. Dissolution reactions were carried out by exposing polished calcite surfaces to experimental solutions with compositions similar to sequestration environments. Instantaneous dissolution rates of calcite were determined from solution analyses using atomic emission spectroscopy. Images of post-reacted samples taken with a vertical scanning interferometer (VSI) facilitated a second, independent calculation of absolute dissolution rates for the calcite surface-orientations of interest. The results from these investigations may lead to the development of relatively simple models for mineral grain shape evolution during dissolution, a process that impacts pore sizes and shapes in subsurface environments.

Tai Lam
SPECTROSCOPIC INVESTIGATIONS OF SUBLETHAL DOSES OF PLATINUM GROUP METALS ON CHICK EMBRYO BONE DEVELOPMEN

Tai Lama, Adam Stahlera, Jennifer Monahana, Marjorie Markopoulosa, Jessica Daghera, Joshua Bakera, Zofia Gagnon, Ph.D.b, and Ioana Pavel, Ph.D.a
aDepartment of Chemistry, Wright State University, Dayton, Ohio
bMarist College, Department of Environmental Science and Policy, Poughkeepsie, NY

Platinum group metals (PGMs) are found at pollutant levels in the environment and are known to bioaccumulate in various plant and animal tissues. Our previous studies showed that chick embryos exposed to PGMs concentrations of 5.0 ppm (LD50) and higher presented skeletal deformities. In this study, the effects of PGMs on the skeleton formation of developing chick embryo tibiotarsi were investigated at sublethal doses through the use of various spectroscopic methods. Chick embryos were injected with 1.0 mL of 1.0 ppm Pd(II), Pt(IV), Rh(III) aqueous salt solutions and a PGM mixture on the 7th and 14th day of incubation. Control groups with no-injection and 1.0 mL injections of saline solutions were included. Embryos were sacrificed on the 20th day and tibiotarsi were harvested. Micro-Raman imaging of the paraffin embedded cross–sections of tibiotarsi revealed anomalous calcium inclusions within the bone marrow for the PGM mixture treatment. Hyperspectral Raman data were analyzed using in house–written codes within MatLab v. 7.11.0 R2010b. Raman univariate chemical maps were created using the baseline–corrected intensity of the n1(PO43–) stretching mode. Significant changes (one–way ANOVA, p = 0.001) in the average mineralization age of tibiotarsi were found in all treatments when compared to controls. More exactly, the Integrated area of n1(CO32–)/ Integrated area of n1(PO43–) was 0.101 ± 0.074, 0.099 ± 0.076, 0.047 ± 0.035, 0.057 ± 0.038, 0.085 ± 0.061 and 0.074 ± 0.049 for the no injection control, the saline vehicle control, Pd, Pt, Rh, and the PGM mixture treatments, respectively. Flame atomic absorption spectroscopy revealed ~50% change in the percent calcium content for the Pd and Pt treatments with respect to the no-injection control (17.05% calcium). PGM concentrations in all tibiotarsi were below inductively–coupled–plasma optical–emission spectroscopy detection levels. Overall, spectroscopic results show sublethal doses of PGMs negatively impact bone development.