Department of chemistry - Posters in the Hall
End of Year Annual Event - 2012
Undergraduate and Graduate Students Present their Research
Undergraduates Student Presenters
Urmimala Chaudhuri
Andria Fortney
Jeremy Lear
Kristy Wickman
Graduate Student Presenters
Catherine B. Anders
Joshua D. Baker
Daniel Brown
Jessica M. Dagher
Mark R. Duffy
Dennis Lennaerts
Ryan Oostendorp
Adam Stahler
Courtney Sutherland
Triet Truong
Abstracts
Electroanalysis of Chlorpromazine (CPZ) Utilizing Cetyltrimethylammoninm Bromide Carbon Paste Electrode (CTABCPE)
Urmimala Chaudhuri, Miyong Hughes, and Suzanne K. Lunsford, Ph.D.,
Wright State University, Department of Chemistry
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.
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.
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.
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
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
Wright State University, Dept. of Chemistry, 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.
"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, 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.
Halogenations of Aryl Substituted Sydnones
Daniel Brown, Jennifer Benson, Ashley Clark, Kyle Liddy, Jeffrey Morehead, Kyle Oxman
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.
Transport of Engineered Silver Nanoparticles through Saturated Porous Media
Jessica M. Dagher*, Sushil R. Kanel#, Allie Meyerhoefer*, Mark N. Goltz#, and Ioana E. P. Sizemore*
*Department of Chemistry, Wright State University, 3640
#Department of Systems and Engineering Management, Air Force Institute of Technology, 2950
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 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.
Dissolution kinetics of gypsum (010) surfaces
Dennis Lennaerts a, Matthieu Martinb, Elliott R. Brownb and Steven R. Higgins a
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 uL) 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.
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.
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, Ioana Pavel Sizemorea
aDepartment of Chemistry, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45434
b Electro-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.
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.
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.
