Chemistry and chemical engineering.
Vice-chair: Ken Lee, Jackson State University
9:00 ECL QUENCHING BEHAVIOR OF RU(BPY)32+/TPRA SYSTEM BY CL- AT AU ELECTRODE: DIRECT EVIDENCE OBTAINED FROM EQCM
Shijun Wang, Wujian Miao
University of Southern Mississippi
Electrogenerated chemiluminescence (ECL) is a process of light generation from electrochemical reactions. For example, light emission can be observed at an electrode placed in contact with an aqueous solution containing luminophore Ru(bpy)32+ (ruthenium (II) tris(2,2'-bipyridine) and an ECL coreactant tripropylamine (TPrA) upon anodic potential scanning. A number of factors such as the nature of the working electrode and the components of the electrolyte could affect the ECL intensity that is often proportional to the luminophore concentrations. Understanding of such effects is important in designing an ECL system that possesses highly reproducible and efficient ECL signals. We report here the influence of chloride ions on ECL at Au electrode for Ru(bpy)32+/TPrA system. Chloride ions commonly exist in biological systems, e.g., in phosphate buffer saline solutions. Direct evidence obtained from electrochemical quartz crystal microbalance (EQCM) experiments will be presented in support our proposed ECL quenching mechanism that involves the electrochemical formation of AuI/III-Cl-complexes. Our data also suggest that caution must be taken when one uses a saturated calomel electrode (SCE) combined with an Au working electrode for ECL studies, since SCE contains high concentrations of chloride ions which could penetrate the porous tip of the electrode to the ECL system. Financial support from NSF-MRSEC grant (NSF-DMR 0213883) is gratefully acknowledged.
9:15 DETECTION OF CHEMICAL NERVE AGENT SIMULANTS: PROGRESS TOWARDS QCM SENSORS
University of Southern Mississippi
Quartz crystal microbalance (QCM) is a sensing tool that used for the detection of toxic chemicals. The change in frequency of the quartz crystal is attributed to the change in mass of the quartz crystal (QC). It is well known that sulfur containing functional groups can act as "anchors" to gold surfaces to form self-assembled-monoayers. The work presented here describes the synthesis of a family of dithiol monomers that contain a reactive functional group, which will bind directly to the stimulant. These monomers then form SAMs onto a gold surface, on a QC platform. The same family of monomers have also been tethered to gold to form nanospheres. The synthesis and characterization of both the monomers, SAMs and the gold nanoparticles, and our initial results using QCM as a sensor towards chemical nerve agent stimulants, will be discussed.
9:30 APPROACHES TO THE SYNTHESIS OF A TITANANTHRACENE
Jahnavi Chatterjee (1), Neil Allison (1)
(1) Mississippi University for Women, (2) University of Arkansas
The goal of this project was to synthesize the transition metallaaromatic compound titananthracene in order to study the fundamental concept of aromaticity and how it applies to this class of metallacycles. Previous unsuccessful attempts have been made to synthesize titananthracene by the removal of a hydride or proton from titanadibenzocyclohexa-2,5-diene. This research focused on replacing a hydrogen at the saturated C(4) position of titanadibenzocyclohexa-2,5-diene with a TMS group. Removal of the TMS group with fluoride is expected to form a titananthracene. The first three steps of the proposed synthetic reaction scheme have been successfully carried out.
9:45 VEGETABLE OIL MACROMONOMER-BASED LATEXES AND WATERBORNE INDUSTRIAL COATINGS
Yvette Abadie, James Rawlins
The University of Southern Mississippi
Vegetable oil-based macromonomers (VOMMs) are a series of vegetable oil derivatives functionalized for facile incorporation into emulsion polymers via random copolymerization with conventional monomers. VOMMs enable good film coalescence and reduce the volatile organic compound (VOC) levels by replacing coalescing solvents in waterborne coatings. Moreover, VOMMs crosslink after application via auto-oxidation. Soybean oil-based VOMMs were synthesized and incorporated into industrial emulsion polymer models at varying VOMM concentrations. The polymers were formulated as waterborne industrial coatings using hexamethoxymethylolmelamine as the crosslinker and evaluated versus a commercial latex at varying latex to crosslinker ratios. Post application crosslinking and material response to deformation was evaluated via dynamic mechanical analysis. The coatings specific properties were measured by comparing data from differential scanning calorimetry, infrared spectroscopy, and ASTM tests. The data confirm that higher VOMM levels improve coating performance mainly quantified through improved solvent and impact resistance, and flexibility testing.
10:00 FRONTAL POLYMERIZATION WITH ENCAPSULATED INITIATORS PREPARED BY SEVERAL METHODS
Christopher Bounds, John Pojman
The University of Southern Mississippi
We studied frontal polymerization with initiators microencapsulated by several techniques. Microcapsules were produced containing benzoyl peroxide, triethylenetetramine, and N,N-dimethyl-p-toluidine using different encapsulation processes with sizes ranging from >400 microns to <100 microns. These microcapsules were subjected to validity and function testing. If the parameters were feasible, frontal polymerization processes were applied to an acrylate or a thiol-ene system containing these microcapsules. It was determined that stability and the size of the microcapsules were important issues in regards to the preparation of a front of polymerization using these microcapsules. When the size of the microcapsules is too large the front velocity is very slow, and in some cases, large microcapsules caused low polymer conversion.
10:30 MASS SPECTROMETRY BASED ASSAY FOR THE ENZYMATIC HYDROLYSIS OF PSEUDOPROCHIRAL MALONATE DIESTERS
Dale Rosado Jr., Cassie Nabors, Douglas Masterson
University of Southern Mississippi
Enzymes (i.e. Pig Liver Esterase) have been proven to be extremely efficient in hydrolyzing derivitized malonate diesters with high selectivity for the R or S enantiomer and with high chemical yield. To date, no assay exists where different conditions for these hydrolyses can be monitored in a rapid and efficient manner. Our group has developed a Mass Spectrometry based assay that allows for quick and efficient monitoring of the selectivity of various enzymes under various conditions. This assay uses pseudo-prochiral (H5, D5) malonate diesters, which need only be enantiomerically enriched, which is hydrolyzed under a variety of conditions and monitored by LDI-TOF or ESI-MS. The peak intensities and areas from the mass spectra were then used to determine an observed ratio of enantiomers, which can then be corrected to give the actual ratio. Chiral HPLC was then used to verify the accuracy of the assay.
10:45 PREPARATION AND CHARACTERIZATION OF TRIS(2,2'-BIPYRIDYL)RUTHENIUM(II)-LOADED MICROCAPSULES AS ELECTROGENERATED CHEMILUMINESCENT LABLES FOR BIOMOLECULES DETECTION Tommie L. Pittman* and Wujian Miao, University of Southern Mississippi, Hattiesburg, MS 39406
Tommie Pittman, Wujian Miao
University of Southern Mississippi
Polymerized liposome-based microcapsules loaded with water soluble tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)32+) as electrogenerated chemiluminescent (ECL) labels for ultrasensitive biomolecule detection is reported. Ru(bpy)32+-loaded liposomes with a biological importance surface functional group, biotin, were prepared on the basis of our recently reported technique. The liposomes were produced from phospholipid molecules such as DSPC and DSPE-PEG(2000)Biotin after solubilization in chloroform along with the addition of 50 mM Ru(bpy)3C12 prepared in 10 mM Tris buffer. Water (containing Ru(bpy)32+)-in-oil emulsion was then formed by vortexing the mixture. The resulting emulsion was layered on 0.1 M Tris buffer. The liposomal solution was transferred to warm water bath and the organic phase (chloroform) was removed by using argon and subsequent addition of low concentrations of styrene monomer and photoinitiator species before proceeding to gently agitation to form Ru(bpy)3C12 multilamellar vesicles. A micro-extruder with suitable pore-sized polycarbonate membranes was then used to produce monodisperse unilamellar vesicles while allowing the styrene monomer and photoinitiator species to penetrate through the outside lipid layer and remain in the hydrophobic zone of the liposome. Photo-polymerization process was carried out and Ru(bpy)32+-loaded microcapsules with a layer of polystyrene was produced. The characterization of polymerized ECL labels was carried out with scanning electron microscopy, optical microscopy, and light scattering techniques. The detection of DNA and protein with above prepared microcapsules using ECL will be discussed.
11:00 FRONT TEMPERATURE AND FRONT VELOCITY AS A FUNCTION OF BENZOYL PEROXIDE CONCENTRATION, TRITHIOL CONCENTRATION AND FILLER LOADING IN THE FRONTAL POLYMERIZATION OF A TRIACRYLATE
Veronika Viner, John Pojman
The University of Southern Mississippi
Frontal polymerization is a localized reaction that propagates from the coupling of the Arrhenius dependence of the kinetics of an exothermic polymerization and the diffusion of thermal energy. The front temperature with multifunctional acrylates, can be as high as 250 [degrees]C. Such high temperatures result in smoking and the release of volatile compound that prevent the use indoors. We studied how the front temperature and front velocity were affected by the addition of fillers, a trithiol, a plasticizer, and benzoyl peroxide. For the monomer we used trimethylol proprane triacrylate. Different types of filler (Poly-gloss 90 and Cabosil) were tested. As filler loading was increased, the front temperature decreased until the propagating front was quenched. As the % plasticizer and % trithiol were increased, the front temperature and front velocity decreased. As BPO concentration was increased, the front temperature and front velocity increased along with more smoke being produced.
11:15 EXO-AND ENANTIOSELECTIVE DIELS ALDER REACTIONS: PYRAZOLIDINONE AUXILIARIES ARE ABLE TO OVERRIDE SECONDARY ORBITAL INTERACTIONS
Mukund Sibi (1), Jessica Shackleford (2), Levi Stanley (1), Xiaoping Nie (1), Frances Bouret (1)
(1) North Dakota State University, (2) University of Southern Mississippi
Due to secondary orbital interactions, the majority of Diels-Alder reactions are highly endo-selective. Despite this general rule, past research shows that there are certain methods for switching the major product of certain Diels-Alder reactions from the endo product to its exo counterpart. We hypothesized that a combination of an appropriate achiral template and a chiral Lewis acid catalyst could overcome the electronic preference to provide access to the exo adduct. Of the various Lewis acids and ligands screened, a combination of Yb(OTf)3 and diphenyl Pybox ligand gave the best selectivity (25:75 endo:exo) while using a dienophile derived from a pyrazolidinone. Once optimal conditions were determined, the achiral template was varied to evaluate the effect of structure on the endo:exo ratio. The maximum effect was observed when the R1 position was altered to an ethyl substitutent, which resulted in a 16:84 endo:exo ratio. The results of these studies will be presented.
11:30 DETECTION OF PEROXIDE-BASED EXPLOSIVES USING ELECTROGENERATED CHEMILUMINISCENCE
Suman Parajuli, Wujian Miao
University of Southern Mississippi
Hexamethylenetriperoxidediamine(HMTD) and triacetonetriperoxide(TATP) are two commonly used peroxide-based explosives. These explosives are frequently used by terrorists because they can be easily synthesized with the readily available chemicals in the market. Herein we report their syntheses, characterization, and particularly their detection using electrogenerated chemiluminiscence(ECL) technique. ECL is a process of light emission at the electrode due to energetic electron-transfer reactions between redox species generated electrochemically. The basis of ECL detection of TATP and HMTD is due to the fact that both compounds contain peroxide moieties and the later contains the tertiary amine, which could act as an ECL coreactant in the presence of an ECL luminophore such as Ru(bpy)32+ (ruthenium(II)tris(bipyridine)) up on anodic or cathodic potential scanning. Effects of electrode materials, enhancement by silver ions on ECL, etc. will be discussed.
1:15 MODIFIED FOX EQUATION TO PREDICT GLASS TRANSITION TEMPERATURES OF VEGETABLE OIL MACROMONOMER LATEXES
Charles White, James Rawlins
University of Southern Mississippi
Vegetable oil-based macromonomers (VOMMs) are vegetable oil derivatives functionalized for efficient incorporation into emulsion polymers via random copolymerization with conventional petroleum derived monomers. VOMMs enable good film coalescence as a plasticizing monomer, and reduce the volatile organic compounds (VOC) by replacing coalescing solvents in waterborne protective and decorative coatings. Moreover, VOMMs have the potential to crosslink after application via auto-oxidation. With their long fatty acid chains, VOMMs have a significant effect on the latex glass transition temperature (Tg) and minimum filming temperature (MFT). However, VOMM-based latexes have not consistently followed the traditional Fox equation used to predict random copolymer Tgs. A series of emulsion polymers were synthesized at varying proportions of VOMMs, and the resulting latexes were analyzed for Tg via differential scanning calorimetry and MFT. For predictive capabilities, modifications to the Fox equation are proposed to facilitate accurate Tg prediction for VOMM-based latexes.
1:30 NAPHTHALIMIDE LINKED ONIUM SALTS AS POTENTIAL PHOTOACTIVATABLE DNA-CLEAVING REAGENTS
Emily Stewart, Jonathan Giurintano, Woods Curry, David Sandlin, Wolfgang Kramer
Nitrogen-onium salts based on aromatic heterocycles contain a fragmentable nitrogen-oxygen bond that is homolytically cleaved upon absorption of light. The fragmentation yields a heteroaromatic radical cation as well as an alkoxy radical. It has been shown that both transient species can cleave DNA, each with a different mechanism. This shows the potential of the nitrogen onium salts for photodynamic therapy creating two separate reactive species with one photon of light. Due to the transient character of the reactive species, ground state association has to be efficient. To increase DNA binding, a naphthalimide moiety was attached to the nitrogen onium salt. A flexible, variable methylen spacer links the two functionalities and might be important to the efficiency of the binding event. The synthetic procedure involves the condensation of homologous amino alcohols with naphthalic anhydride and subsequent coupling with a heteroaromatic compound. The ground state association is determined by absorption and transmission spectroscopy. To test for photodynamic therapy potential of the newly synthesized onium salts, the photobiological impact was determined using Saccharomyces cerevisiae as a test system. Cytotoxicity was determined to establish a tolerance level of drug. The cells were then incubated with this concentration and subsequently irradiated.
1:45 PREPARATION OF HOMOCHIRALLY SIMILAR ISOLEUCINE ANALOGUES THROUGH A COMMON SYNTHETIC INTERMEDIATE
Sandipan Dawn, James Shows, Douglas Masterson
The University of Southern Mississippi
Preparation of different peptides containing unnatural amino acids is a huge interest among researchers last few years. These peptides usually have enhanced biological activity and/or longer half-life as proteolytic enzymes do not recognize these peptide bonds readily. Scientists around the world have been trying to synthesize [alpha]-, [beta]-, [gamma]- varieties of unnatural amino acids to incorporate them into these peptides. There are several different approaches to synthesize these unnatural amino acids but there is no common synthetic strategy through which one can produce all these derivatives via a common intermediate. As it currently stands, preparation of each class of amino acids requires its own special procedure. The currently used syntheses make it extremely difficult to prepare several homochirally similar amino acids simultaneously. This presentation will illustrate our effort to generate different homochirally similar isoleucine anlogues through a common half-ester intermediate. It is also noteworthy that unlike other amino acids isoleucine has a chiral center at its side chain leading the synthetic project more challenging.
2:00 STUDY IN THE REACTION OF CYANAMIDE WITH 1,3-DIAMINOPROPANE: FORMATION OF MELAMINE AND TETRAHYDRO-2-PYRIMIDINONE
Ken Lee (1), Ed Valente (2), Vyvyca Jones (1)
(1) Jackson State University, (2) Mississippi College
Endogenous agmatine, which is neuroprotective and a neurotransmitter, binds to [alpha]2-adrenergic receptor and imidazoline binding sites, and blocks NMDA receptors and other cation ligand-gated channels. Agmatine inhibits nitric oxide synthase (NOS), and induces the release of some peptide hormones. The enzyme, agmatinase, degrades it into polyamine. We are interested in controlling the level of agmatine by inhibiting agmatinase and have designed several derivatives. A previous experiment reported that 3-aminorpopyl guanidine (APG) was prepared from the coupling reaction between cyanamide and 1,3-diamino propane. However the reaction produces APG as a minor product with two byproducts, melamine and tetrahydro-2-pyrimidinone. Two byproducts were analyzed by NMR, MASS and X-Ray Single Crystallography. The reaction mechanism has been proposed and will be discussed.
This research was supported by NIH (R21 NS054862-01 and RCMI, NIH-NCRR G12RR13459) and NSF STARGE programs (NSF-HRD-0411559).
2:30 STUDY OF CHEMICAL COMPOSITIONS OF AN AFRICAN EDIBLE PLANT VERNONIA AMYGDALINA (VA)
Xuan Luo, Daniel Oyugi, Danielle Payton, Ernest Izevbigie, Ken Lee
Jackson State University
Breast cancer is one of most frequent cancer types, among women. Our interest is in finding a novel and effective breast cancer chemotherapeutics from a folk medicine. An aqueous extract of an African edible plant, Vernonia amygdalina (VA) leaf, has been reported to be potent to breast tumor cell line MCF-7. We used 85% EtOH to extract organic components from VA leaf. The condensate was separated with two methods, liquid--liquid method (Method A) and Silica gel method (Method B). Three and five fractions were obtained from Method A and B, respectively. Comparing these fractions' bio-activity, Method A yielded more concentrated with active compounds than Method B. A-2 showed the highest bio-activity. Column Chromatography was used to separate A-2 into five parts (A-2-A, A-2-B, and so on) in methanol--chloroform solvent system. The bio-assay data indicated that active compounds still kept in A-2-B. We used TLC, UV, IR, HPLC, and NMR (1H and 13C) to analyze A-2-B. Gel filtration chromatography with Sephadex[TM] LH-20 was used to separate A-2-B in methanol--chloroform solvent system, and the UV data showed that it separated into five parts. The NMR spectra of separated portions will be presented with result of bio-assay. Bioassay was done on MCF-7 cell line with [3H]-thymidine method. We thank NIH (RCMI: NIH-NCRR G12RR13459, NCMHD: P20MD000534-01, and MBRS-RISE: R25GM067122-03).
2:45 PEPTIDOMIMETICS : SYNTHESIS AND INCORPORATION OF UNNATURAL CYSTEINE ANALOGUES INTO BIOACTIVE PEPTIDE
Kinkini Roy, Douglas Masterson
The University of Southern Mississippi, Department of Chemistry and Biochemistry
It has been shown that incorporation of unnatural amino acids into protease specific sites in small peptides (somatostatin) increases the in vivo half-life of the peptide. Much attention has been given to the so called [alpha]-, [beta]-, [gamma]-peptides which are composed of [alpha]-, [beta]-, [gamma]-amino acids. The current interest in these unnatural peptides has provided an opportunity for chemists to design amino acid preparation which are simple, efficient, and general. There is a lack of general syntheses which can be used to prepare a wide variety of amino acid classes from simple, high yielding transformations. As it currently stands, the preparation of each class of amino acids requires its own special procedures. The currently used syntheses make it extremely difficult to prepare several homochirally similar amino acids simultaneously. This presentation will illustrate our efforts to develop syntheses which can be used to construct a wide variety of cysteine analogues ([alpha]-, [beta]-, [gamma]-) from a common intermediate. We are now trying to prepare glutathione analogue by replacing the natural cysteine by its unnatural counterpart. We believe these unnatural peptides should have longer half life.
3:00 CONVECTION INDUCED BY GRADIENTS IN EFFECTIVE INTERFACIAL TENSION
Joey Emfinger, John Pojman
University of Southern Mississppi
When two miscible fluids are in contact, an effective interfacial tension (EIT) can exist. This EIT eventually relaxes two zero as the fluids diffusion and create an equilibrium, uniform solution. However, for some systems near a consulate point, the concentration gradient can remain large for a significant period of time. For example, isobutyric acid and water are miscible above 26 [degrees]C, its Upper Critical Solution Temperature (UCST) and form two phase below that temperature. By heating a sample from below to above its UCST, we can create a sharp but transient interface. The fluid motion caused by imposed temperature and concentration gradients was studied.
3:15 Business Meeting and Awards
6:00 Dodgen Reception and Divisional Poster Sessions Please set up between 4:00p and 4:30p Location: Grand Ballroom
MONO AND BINUCLEAR COPPER COMPLEXES OF SALICYLIDENE SCHIFF BASES: SYNTHESIS AND CHARACTERIZATION OF MESOGENIC PROPERTIES
V S Rao Nandiraju (1), Choudhury Trirup D (1), Paul Manoj (1), Francis Tuluri (2)
(1) Assam University, India, (2) Jackson State University
The synthesis of new mono and binuclear copper (II) complexes derived from Schiff bases viz., N (4-alkyloxysalicylidene)-4/-n-alkylanilines are carried out and their liquid crystalline properties have been investigated. The liquid crystalline phases were characterized by differential scanning calorimetry (DSC) analysis, optical polarized microscopy, and powder X-ray diffraction spectroscopy at different temperatures. The mono copper (II) complexes exhibit different smectic phases, while the binuclear copper (II) complexes exhibit viscous liquid crystalline smectic A phase. The binuclear copper (II) complexes are thermally stable even at high temperatures above the smectic-isotropic transition temperature. The isotropic-liquid crystalline transition temperatures of the binuclear complexes in general are found to be lower than their corresponding mononuclear homologues. It was found that the mononuclear complexes exhibit sharp liquid crystalline-isotropic transition temperatures while the binuclear complexes melts over a temperature range. Temperature variation of X-ray diffraction studies revealed the difference in inter-molecular distances of mono and binuclear copper (II) complexes.
DEOXYGUANOSINE ADDUCT FORMATION OF 2-HYDROXY-1,4-DIOXANE
Brittny Davis (1), Andrew Brown (2), James Fishbein (2)
(1) Jackson State University, (2) Unviversity of Maryland, Baltimore County
N-nitrosomorpholine is a known carcinogen, found in foods, groundwater, personal care products, and endogenous formation. Through a p450 hydroxylation reaction, N-nitrosomorpholine is converted to a more cytotoxic compound, [alpha]-hydroxy-N-nitrosomorpholine. [alpha]-hydroxy-N-nitrosomorpholine decomposes to several by-products that may be cytoxic as well. The focus of this research was to study 2-hydroxy-1,4-dioxane, a by-product of [alpha]-hydroxy-N-nitrosomorpholine, and to determine its effect on deoxyguanosine (dG). A one milliliter solution of 100mM 2-hydroxy-1,4-dioxane and 1mM dG were reacted in Cacodylic acid buffer, pH of 7.0, at room temperature. The products were analyzed by High Pressure Liquid Chromatography (HPLC) using UV detection. The products that were found may be the proposed product or other products that were not calculated; however, stability studies, Nuclear Magnetic Resonance, and Mass Spectroscopy characterization will be carried out on those products. So far, the products have been collected and separated through HPLC. Future research would include characterizing the products that were found, but if the proposed adduct is found, it would lead to more research involving 2-hydroxy-1,4-dioxane and other nucleic acid bases, and eventually DNA. This research experience was supported by: The FASEB MARC Program (Bethesda, MD) through a Grant from NIGMS/NIH > (T36--GM08637) for travel award funding to UMBC Summer Biomedical Training Program, a Grant from the National Cancer Institute, NIH, and the MARC Program at Jackson State University, grant (5-T34-GM007672-28).
SYNTHESIS AND CHARACTERIZATION OF SOME FLUORINE-CONTAINING COMPLEXES OF RUTHENIUM(II): USE OF 19F NMR IN STUDYING DNA INTERACTIONS
Lamaryet Moody (1), Marauo Davis (1), Varma H. Rambaran (2), Luke Seymour (1), Woodrow Ward (1), Eva Clark (1), Don vanDerveer (3), Suman Parajuli (1), William Jarrett (1), Wujian Miao (1), Alvin A. Holder (1)
(1) The University of Southern Mississippi, (2) The University of Trinidad and Tobago, Trinidad and Tobago, (3) Clemson University
Several novel ruthenium(II) complexes with novel fluorinated ligands were synthesized. The ruthenium(II) complexes were characterized by UV-visible, IR, NMR, and mass spectroscopy, and X-ray crystallography. Electrochemical studies were carried out on the complexes in CH3CN and aqueous solutions so as to detect the redox potentials of the ruthenium(II) metal center and the effect of ligand environment on the redox potential of ruthenium(II). Detailed 19F NMR studies involving the interaction of these complexes with DNA plasmids will be discussed.
SYNTHESES AND CHARACTERIZATIONS OF SOME TRANSITION METAL COMPLEXES CONTAINING ANALOGUES OF 2,6-PYRIDINEDICARBOXYLIC ACID
Shawna Balof (1), Lamaryet Moody (1), Shanika Smith (1), Varma H. Rambaran (2), Don vanDerveer (3), Alvin A. Holder (1)
(1) The Univeristy of Southern Mississippi, (2) The University of Trinidad and Tobago, Trinidad and Tobago, (3) Clemson University
Novel transition metal complexes containing analogues of 2,6-pyridinedicarboxylic acid with various types of amines, either coordinated or uncoordinated, have been synthesized. The metal complexes, which have been isolated and described contain cobalt(II), nickel(II), or copper(II) metal centers. Their structures have been elucidated by electronic, vibrational, and NMR spectroscopy. X-ray crystallography was also used to unambiguously elucidate their structural features. Electrochemical studies of these complexes in DMSO revealed the redox properties of the central metal ions and the ligands. Structural and reactivity properties will be discussed in terms of these experimental results.
STABILITY OF CATFISH ANTIOXIDANT CONTAINING BIODIESEL UNDER ACCELERATED STORAGE CONDITIONS
Supanee Danviriyakul (2), Saowalee Jongrattananon (1), Juan L. Silva (1)
(1) Mississippi State University, (2) 1 Chandrakasem Rajabhat University, Thailand
The effect of an antioxidant on the properties of catfish biodiesel under accelerated storage conditions was studied. The samples with (800 ppm TBHQ) and without antioxidant (control) were stored at 80oC for 28 days. At specified time intervals, samples were taken out for analysis of peroxide value, anisidine value, TBARs, acid value, iodine value, UV absorbance, and induction time. The progress in the oxidation was slow at the beginning of the storage. Only small increases in peroxide value, anisidine value, acid value, and UV absorbance were observed from both control and TBHQ added samples. The changes were, however, more pronounced in the control sample. After 21 days, peroxide value, acid value, and UV absorbance started to rise very rapidly. The induction time was increased by the addition of TBHQ at 800 ppm. Changes during storage were not conclusive due to the variations in the measured value, especially at higher values. With the addition of an antioxidant, catfish biodiesel can withstand adverse conditions much better than the control, showing only slight changes in the measured values. Anisidine value, acid value, and UV absorbance were among the potentially oxidative index candidates that can be used to predict the quality of biodiesel related to its effect on engine performance
ANALYSIS OF REFRACTIVE INDEX OF TEMPERED AND NON-TEMPERED FLOAT GLASS
Katrina Battle (1), Jodi Webb (2)
(1) Jackson State University, (2) Federal Bureau of Investigation
Associations made between glass specimens in casework are based on the theory that the variation in refractive index (RI) within a source of glass is smaller than the variation between two different sources. While it is known that refractive index and compositional analysis can be used to discriminate sources of glass, it has been theorized that by using these methods it may be possible to identify the source of this unusual glass. The purpose of this study was to observe any changes in the refractive index measurements of automotive glass. Each sample of glass was broken into very small fragments and mounted on glass microscopic slides for refractive index measurements. The GRIM 3 (Glass Refractive Index Measurement system) was used to perform the RI measurements. One specimen was identified that has a refractive index that departs significantly from that of the specimens that typically occur in casework. A second specimen was identified that has an unusually low refractive index. Both of these automobiles were manufactured outside of the United States. The refractive index measured for remainder of the specimens analyzed for this study fell within the expected values for automotive glass. This study identified one possible source of the glass with unusually high refractive indices, and one source of glass with unusually low refractive index. This research was in part supported by the Minority Access to Research Careers Undergraduate Student Training in Academic Research (MARC/*USTAR) Program (NIH-MARC 5 T34 GM007672-27).
PREPARATION OF ACTIVATED 4-CYANODITHIO PENTANOIC ACID (CTP) AND RAFT POLYMERIZATION OF FREE AMINE CONTAINING POLYMERS
Nathan Barnett (1), Alp Alidedeoglu (2), Sarah Morgan (2)
(1) Mississippi School for Mathematics and Science, (2) University of Southern Mississippi: School of Polymers and High Performance Materials
Reversible addition- fragmentation chain transfer (RAFT) polymerization was used to create polymers capable of performing a silicon surface RAFT polymerization. To perform this RAFT polymerization, activated 4-cyandithio pentanoic acid (CTP) was created (structure was confirmed by nuclear magnetic resonance) from a dithioester intermediate and ethyl acetate, and samples of activated CTP were reacted with two different monomers, aminoethyl methacrylamide (AEMA) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPA). The polydispersity index (PDI) of the monomers was tested using gel permeation chromatography and resulted in a PDI of 1.12 and 1.14 for AEMA and AMPA, respectively. These polymers are now ready for a surface RAFT polymerization on a silicon wafer sonicated in toluene. Future experimentation will create a fluid with low surface friction that will have many biomedical applications, one being the creation of synthetic fluid for joints in the human body.
ACETYLCHOLINESTERASE INHIBITORS IN HERBS AND SPICES
Mississippi School for Math and Science
Alzheimer's disease (AD) is one of the world's most dominant diseases among the elderly. More than five million people in the United States have been diagnosed with AD. AD has been known to cause memory loss, and in many cases, death. Patients with AD have a deficiency in the neurotransmitter acetylcholine (Ach) and a build up of beta-amyloid plaque. There is also a progressive loss of neurons in the fore brain. Deficiency of Ach and build up of beta-amyloid plaque on the brain impair the neurons from delivering messages. There is no real cure for AD so yet. Several treatments including acetylcholinesterase (AchE) inhibitors and glutamate regulators have been developed that can temporarily ease symptoms. AchE inhibitors slow down the degradation of Ach thereby maintaining a significant level of Ach in the brain for normal neuronal functions. One such treatment includes Galantamine, a natural product isolated from the bulbs of Caucasian snowdrops (Galanthus nivalis). Recent studies have shown that curcumin, the dark yellow compound with strong antioxidant activity isolated from turmeric, a yellow spice used in Asian cuisine, inhibits the build-up of beta-amyloid plaque in the brain. In this research, an attempt was made to search for acetylcholine esterase (AchE) inhibitors in herbs and spices that are used in food. Thus, people can consume such foods at an early stage of onset of AD to ease the symptoms of the disease.
GELATIN SUSPENDED CARBON NANOTUBE ALIGNMENT AND DIFFERENTIATION UTILIZING IODIXANOL
Irma Hamilton (1), Andy Walsh (2), Anna K. Swan (2)
(1) Jackson State University, (2) Boston University
Carbon nanontubes (CNTs) are a cylinder formed from a sheet of graphite with diameter of the order of a nanometer. CNTs have great strength which is attributed to their being composed entirely of sp2 bonds. CNT application includes electronics, optics, and biosensors because of its novel electronic and optical properties. Single-walled CNTs production, the tubes are bundled because of the large van der Waals forces. The CNTs were encapsulated with detergents such as sodium dodecyl sulfate (SDS) and sodium cholate (SC) which have a hydrophobic tail and hydrophilic head. Sonication of the detergent and the CNT mixture was performed to increase dispersion of individual CNTs. After encapsulation and sonication, centrifugation and ultracentrifugation were utilized at varying time lengths to remove aggregates. This removed the large bundles. A new method developed at Northwestern University is able to truly separate the tubes according to bundling and even more interestingly by diameter. This method utilized centrifugation in a density gradient using iodixanol. When the initial nanotube distribution has a sufficiently small diameter distribution, like the CoMoCat sample, it is possible to separate out only metallic or only semi-conductive nanotubes by changing the ratio of SC and SDS. This is of high technological importance. A gelatin suspension was created from the top layer recovered after centrifugation and "combed" through in order to achieve aligned, individual CNTs. The degree of alignment was measured using a Cary 500 spectrometer to determine the polarization dependent absorption.
THEORETICAL STUDY OF THE ADSORPTION OF ORGANOPHOSPHORUS COMPOUNDS ON METAL OXIDE SURFACES
Yuliya Paukku, Andrea Michalkova, Jerzy Leszczynski Jackson State University, Computational Center for Molecular Structure and Interactions
Organophosphorus compounds (OP), powerful inhibitors of the enzymes involved in nerve function, are widely used as insecticides as well as nerve agents. The high acute toxicity of these compounds underscores the need to detect, decontaminate, and destruct these chemicals in order to protect human health and ecosystems Oxides of many metals are highly ionic and high melting, and their surfaces exhibit both Lewis base and Lewis acid character. Among these oxides calcium oxide (CaO) and zinc oxide (ZnO) were chosen for this work to investigate the adsorption and decomposition of selected organophosphorus compounds (dimethyl methylphosphonate (DMMP)).
All calculations have been carried out at the DFT/B3LYP levels of theory applying the 6-31 G(d) basis set. The geometry of target molecule is fully optimized while the geometry of the oxide fragments is kept frozen. The structure, interactions and interaction energy (corrected by the basis set superposition error) of the adsorption systems have been studied. The difference in the geometrical parameters and atomic charges of adsorbed and isolated DMMP has been analyzed. DMMP was found to be chemisorbed on the non-hydroxylated ZnO and CaO surfaces. DMMP is bound to the zinc oxide surface through the formation of strong chemical bonds between oxygen atoms of DMMP and zinc atoms of the ZnO surface. Adsorption of DMMP on calcium oxide surface occurs via formation of a P-O chemical bond. The adsorption leads to structural changes of the target molecule and to its polarization.
CATALYTIC GASOLINE SYNTHESIS: UPGRADING OF SYNTHESIS GAS INTO GASOLINE RANGE HYDROCARBONS OVER ION EXCHANGED BIFUNCTIONAL CATALYST.
Xiaotian Liu, Amit Gujar, Hossein Toghiani
The Mississippi School for Mathematics and Science
Synthesis gas can be produced directly from gasification of the biomass. Upgrading synthesis gas into gasoline range hydrocarbons has attracted a significant amount attention as an alternative way to produce motor fuels. Many have tried to use a physical mixture of metal and zeolite catalyst to upgrade synthesis gas into gasoline range hydrocarbons, but the physical difference has limited the efficiency of the transformation process. In this experiment, copper was ion exchanged into HZSM-5 to form Cu/HZSM-5 catalyst. The catalyst was then tested in the flow reactor at 300-350oC under pressure of 700-1200 psig with 1:1 ratio of H2: CO. It has shown that the temperature and pressure has a direct effect on hydrocarbon productivity. The composition of gas sample and the two phases of the liquid sample (hydrocarbon phase and water, alcohol phase) have been analyzed using GC. The physical characteristic of the Cu/HZSM-5 are been tested and studied. The experimental data has shown that Cu/HZSM-5 can produce gasoline range hydrocarbons efficiently and produces few little byproducts.
ENANTIOSELECTIVE SYNTHESIS OF HETEROCYCLES USING THE DECARBOXYLATIVE PHOTOCYCLIZATION
Andrew Olinger, Wolfgang Kramer
In the decarboxylative photocyclization a chromophor, usually phthalimide, and a ?-carboxylate are cyclized to yield a heterocycle. The reaction proceeds via a triplet biradical and is thus not stereospecific. Stereospecificity can be achieved by rotational restrictions that store any substrate chirality in the intermediate triplet biradical and yield a stereospecific product. An example is the synthesis of pyrrollo-[1,4]-benzodiazepines that has an axial chiral triplet 1,7-biradical intermediate based on the rotational barrier between anthranilic acid and phthalimide and yields only one diastereomeric isomer in the cyclization reaction. Usually, the carboxylate is generated by deprotonation with potassium carbonate. The potassium appears to serve as a template bringing the radical centers together, even a ground state association has been discussed. Other cations give lower yields of cyclization product. Using a chiral amine adds a chiral component to the reaction mixture and leads to the formation of a chiral salt. The photoreaction then proceeds to yield an enantiomeric excess of one stereoisomer. We studied a series of cyclization reactions leading to heterocycles with different ring sizes varying the salts and monitoring the enantiomeric excess.
ONIUM SALTS AS POTENTIAL PHOTOACTIVATABLE DNA-CLEAVING REAGENTS
David Sandlin, Emily Stewart, Jonathan Giurintano, Woods Curry, Wolfgang Kramer
The fragmentable nitrogen-oxygen bond in nitrogen onium salts can be homolytically cleaved by light. This leads to the formation of of a heteroaromatic radical cation and an alkoxy radical. It has been shown that both transient species can cleave DNA, each with a different mechanism. This shows the potential of the nitrogen onium salts for photodynamic therapy creating two separate reactive species with one photon of light. Due to the transient character of the reactive species, ground state association has to be efficient. To increase DNA binding, a naphthalimide moiety was attached to the nitrogen onium salt. A flexible, variable methylen spacer links the two functionalities and might be important to the efficiency of the binding event. The synthetic procedure involves the condensation of homologous amino alcohols with naphthalic anhydride and subsequent coupling with a heteroaromatic compound. The ground state association is determined by absorption and transmission spectroscopy. To test for photodynamic therapy potential of the newly synthesized onium salts, the photobiological impact was determined using Saccharomyces cerevisiae as a test system. Cytotoxicity was determined to establish a tolerance level of drug. The cells were then incubated with this concentration and subsequently irradiated.
PREPARATION OF HOMOCHIRALLY SIMILAR LYSINE ANALOGUES FROM A COMMON SYNTHETIC INTERMEDIATE
Douglas Masterson, Kinkini Roy, Jessie Geoghegan, Shimeka Banks
The University of Southern Mississippi, The Department of Chemistry & Biochemistry
The goal of this project is to develop a way to synthesize unnatural Lysine analogues, from a common synthetic intermediate. The ultimate goal is to use these Lysine analogues to make small peptides which may potentially aid in cancer treatment. The unnatural amino acid analogues can be incorporated into peptide Somatostatin by replacing the natural lysine. It has been shown that the peptides with the unnatural analogues have a longer half life in serum than the peptides with the natural amino acids. These peptides may potentially be used to specifically deliver drugs to cancer cells. In this project, diethylmethylmalonate is used as the staring material. N-(4-Bromobutyl)-phthalimide is then introduced as a protective side chain for lysine. This gives a prochiral diester. One of the ester groups is then selectively hydrolyzed by PLE enzyme which gave half ester with 96% enantiomeric excess. By using different simple organic synthetic pathway we can convert this half ester to unnatural [alpha]-, [beta]-, [gamma]- Lysine
RESEARCH ON BIODIESEL FROM WASTE OILS
Ashley White, Bruce Wenzel, Ken Lee
Jackson State University
Petroleum supplies are being deminished while the worldwide demand is increasing. The US must import petroleum from politically instable areas. Therefore, there is a large research effort for liquid fuels from renewable resources within the States like to produce synthetic diesel fuel from vegetable oils including waste used oils. We have investigated pretreatment of the used oils to handle free fatty acids, water and other components, which inhibit transesterification. It included basic catalyst beside sodium methoxide. Characterization and quantification of triglycerides and the methyl ester were achieved by 1H NMR, IR, and GC/MS. We determined the acidity of several used oils: Acidity, defined as mg KOH/ g sample, ranged from 1.0 to 14.0 for used oils, since they were degraded into short chain fatty acids, while pure vegetable oil and oleic acid have an acidity of 0.2 and 210, respectively. Water content of used oils was determined to be less than 0.1%. The yields of conversion to methyl esters were 82% and 84% for olive and vegetable oil. Data for yields of used oils will be presented. The fatty acid composition of the starting triglycerides of the vegetable oils was mainly stearic (80%) and oleic (20%), and the same for the methyl ester products. The used oils had less of these, instead it has more of short chain fatty acids. We thank DOE-MRT/SBIR DEFG3605G085002/07-08-001, NSF STARGE (HRD-0411559) and NIH-RCMI (R21 NS054862-01) programs.
DIRECT OBSERVATION OF CELLULOSE ACETATE SEPARATED FROM SAWDUST BY SCANNING ELECTRON MICROSCOPE AND DETERMINATION OF LIGNIN FROM SAWDUST AND LEFTOVER FROM THE REACTION IN IONIC LIQUID
Jeffrey Thorn, Samantha Ford, Maria Begonia, Huey-MIn Hwang, Quinton Williams, Ken Lee
Jackson State University
Green chemistry has received a great deal of attention since it reduces the usage of hazardous materials in the chemical process. Some ionic liquids can dissolve cellulose at the elevated temperature. Therefore, we have attempted to separate the cellulosic material from lignin in soft pinewood sawdust using ionic liquid. In order to confirm the conversion other than Infrared spectroscopy, a comparison study on the solid separated from sawdust before and after the reaction has been done with scanning electron microscope. Sawdust before and after grinding shows its clean wall and the distinctive shape of wood. Crystalline cellulose shows the shape of aggregated fiber. The picture from the undissolved brown powder of the reaction shows the thin structure, but mostly similar shape as sawdust. Most interestingly the dark brown powder, which is soluble in ionic liquid, shows the cheese type chuck shape with non-crystalline structure. The lignin contents was analyzed for sawdust and undissloved brown powder with acetyl bromide method. Three pure lignins, lignin alkali, lignosulfonic acid and lignin carboxylate, were used for the standardized line. The lignin contents from sawdust and separated powder were determined several times. The result shows that the lignin contents in powder separated (7.9%) is slightly higher than that of sawdust (7.6%). This research was supported by the DOE-MRT/SBIR DEFG3605G085002/07-08-001,NSF STARGE (HRD-0411559) and NIH MBRS-RISE (R25GM067122-03) programs. We thank FEI Company for the Phenom (SEM).
UNDERSTANDING THE MECHANISM OF [beta]-ODAP NEUROTOXICITY
Luella Jones (1), Ashle Hilbrand (1), Leah Chase (1)
(1) Alcorn State Universtiy, (2) Hope College
[beta]-ODAP is a neurotoxin that is found in the Lathyrus satvius seeds, commonly known as the grass pea. It has been known to cause neurolathyrism which is characterized by the paralysis of the legs and has many qualities that are similar to Parkinsons disease. [beta] -ODAP is a competitive inhibitor of system xC- and a non-NMDA glutamate receptor agonist. System xC- is a transport system involved in the extracellular exchange of cystine for intracellular glutamate across the plasma membrane of a glial cell which helps in the regulation of oxidative radicals. Previous research in our lab has suggested that [beta]-ODAP neurotoxicty may result from the sequestration of [beta]-ODAP by glial cells mediated by system xC-. [beta]-ODAP is hypothesized to undergo heteroexchange with extracellular cystine, resulting in overactivation of non-NMDA receptors, and eventually cell death. The second hypothesis is that [beta]-ODAP acts as an agonist to non-NMDA glutamate receptors which inhibit glutathione synthesis which leads to oxidative cell death. The objective of this study was to synthesize [beta]-ODAP to use HPLC to determine that [beta] -ODAP is taken up and stored in the cell, and to demonstrate that [beta] -ODAP undergoes heteroexchange with cystine by means of system xC-.
A COUPLED-CLUSTER ANALYSIS OF MOLECULES CONTAINING SULFUR AND NITROGEN USING CONVENTIONAL AND THE CC-PV(X+D)Z BASIS SETS
Jackson Stste University
Molecules containing one sulfur and two nitrogen atoms have been of interest for sometime. The combination of an H2S and an N2 molecule is speculated to generate up to 10 possible isomers, and numerous intermediates and transition states in the gas phase. In this study we will consider each isomer of the singlet neutral species, and the doublet radical cations. In previous theoretical studies, the potential-energy surface of H2SN2 species has been studied with MP2 and DFT methods, and CCSD(T) single-point energies have been calculated at the MP2 and DFT geometries. We have extended prior theoretical works on these H2SN2 isomers using the CCSD(T) method to obtain geometries, relative energies, vibrational frequencies, heats of formation, and torsional barrier energies. Possible transition states that connect the reactants to products using the Intrinsic Reaction Coordinate (IRC) were found at the MP2/6-311++G(2d,2p) level. In recent years the traditional Pople and Dunning style basis sets for sulfur and other third row atoms have been criticized for giving unacceptable energy errors when compared to experiment. This error has been noted to be between 6-10 kcal/mol. The cc-pV(X+d) basis set is intended to reduce this error by adding a tight d function specifically on sulfur. We will compare the results from these different types of basis sets to gain some insight and hope to determine the relative significance of basis set effects for the systems considered in this study.
SENSITIVE ANALYSIS OF AMINO ACIDS BY USING HPLC WITH FLUORESCENCE DETECTION
Katrina Battle, Contessa Avery, Yiming Liu
Jackson State University
Analysis of amino acids is very important in a variety of research areas. Gas chromatography methods have been developed for the analysis of amino acids with preparation times up to 2-1/2 hours. The goal of this work was to evaluate a sensitive HPLC method with fluorescence detection for the analysis of amino acids after Fe304 nanoparticle--based extraction. Fe304 nanoparticles coated with OH-, TCPO, DDAB, and DCA were evaluated. Glutamate, Glutamine, Valine, and Trytophan (amino acids) was used as test compounds. The effects of properties such as polarity, extraction conditions, vortex time and nanoparticles amount was studied. Extraction efficiencies were determined for nanoparticles using HPLC and Gas Chromatography analysis was used for comparative study.
PHOTO-INDUCED TOXICITY OF NANOCRYSTALS OF CADMIUM SELENIDE
Sabri Agachan (1), Zikri Arslan (1), Ibrahim Farah (1), Weiyong Yu (2)
(1) JAckson State University, (2) Worcester Polytechnic Institute
The goal of this study was to investigate the photo-induced toxicity of CdSe quantum dots (nanocrystals) in vivo. Bulk CdSe is toxic, but little is known about the stability and toxicity of luminescence nanocrystals of CdSe. Rats were used as model animals. Quantum dots of CdSe stabilized with TOP/TOPO in chloroform were converted to water-soluble form by reacting with thioglycolic acid. Carboxylic acid groups were neutralized by reacting with NaOH. The precipitate resulting from the reaction was solubilized in water. A second portion of water-soluble crystals was irradiated under a 365 nm UV light for 5 h before injection. Substantial deterioration was observed in the nanocrystals as manifested by the loss of CdSe absorption maximum at 582 nm. Both UV irradiated and unirradiated nanocrystals were injected to three different groups of rats at 20, 200 and 500 [micro]g/mL. Each rat received 1 mL injection of CdSe 5 times over three weeks (once every four days). In the end, rats were sacrificed to collect the internal organs, including the heart, liver, kidney, lungs and brain. Visual inspection revealed that liver was the main target organ impacted by the CdSe toxicity. All organs were digested in nitric acid by microwave-assisted digestion procedure and analyzed by ICP-AES to determine the distribution and accumulation rate of the nanocrystals in the in the organs. The results of the instrumental findings and pathology assays were statistically evaluated to elucidate the potential health risks of therapeutic exposure to CdSe nanocrystals.
CHROMATOGRAPHIC AND NMR ANALYSIS OF 9-METHYL-10-NITROANTHRACENE AND ITS PHOTOPRODUCTS
Gernerique Stewart, Ashley Chornes, Yuguo Jiao, Hongtao Yu
Jackson State University
Nitro substituted Polycyclic Aromatic Hydrocarbons (nPAHs) are a class of carcinogenic and mutagenic compounds found in the environment. nPAHs occur several magnitudes lower than their parent PAHs and are more toxic. Nitro-PAHs undergo various chemical reactions in the environment including photochemical reaction. It has been proposed that the photochemical reaction mechanism of nPAHs depends heavily on the position of the nitro group, whether it is co-planar or perpendicular to the aromatic rings. The co-planar nPAHs usually undergo photochemical oxidation of the aromatic rings, while the perpendicular nPAHs undergo rearrangement of the nitro group first to a nitrite and then to nitroso substituted ketone, which is not stable and easily oxidized to quinones. However, the nitroso substituted ketone intermediate has never been isolated and characterized. In this study we use 9-methyl-10-nitroanthracene (I) to study the rearrangement reaction, theorizing that the presence of the methyl group will help to trap the nitroso substituted ketone intermediate. Indeed, irradiation of I with a UVA lamp (365 nm) in chloroform, methanol, or methanol/water mixture generates the main product that has the molecular mass of the nitroso substituted ketone intermediate. We then isolated and identified the it using different chromatographic techniques: TLC and Silica Gel Column Chromatography. The solvent system consisted of 88% Hexane, 10% Ethyl Acetate, and 2% Methanol. Other techniques used during the experiment were the operation of the rotovapor, and NMR.
CHROMATOGRAPHIC AND NMR ANALYSIS OF 4-CHLORO-1,2-PHENYLENEDIAMINE AND ITS PHOTOPRODUCTS
Shuguang Wang, Keonia Smith, Gernerique Stewart, Hongtao Yu
Jackson State University
4-Chloro-1,2-phenylenediamine (CPD) is an aromatic amino compound used as an active ingredient for the production of hair dyes. When exposed to UV light, CPD is known to be mutagenic in bacteria. It is theorized the photochemical reaction and the associated reactive species are two factors responsible for the phototoxicity of CPD. Therefore, the photochemical reaction of CPD is investigated. CPD was dissolved in water and irradiated with a solar simulator lamp (Suntest, 1500 W Xe Lamp with light output intensity of 250 J/cm2). The CPD solution was irradiated for 5 hrs and about 90% of the original CPD disappeared. One main photoproduct was detected by both High Pressure Liquid Chromatography (HPLC) and Thin Layer Chromatography (TLC). The solution was freeze-dried and a brownish solid photoproduct mixture was obtained. The brownish photoproduct was separated on a silica gel column. The solvent system consisted of 70% ethyl acetate and 30% hexane. The solvent was removed by evaporation, and a solid product collected. The product had a molecular mass at m/z 244 (100%) and an isotope ion at 246 (30 %). This molecular mass indicates that the product is likely dimerized since CPD's molecular weight is 142.6 and the isotope ratio of 3:1 for ions 244/246 indicates that only one chlorine atom remains in the photoproduct. 1H-NMR (d6-DMSO) was performed on a 300 MHz Bruker NMR. The results match the previously published NMR spectra for 2,3-diamino-7-c hlorophenazine, C12H9N4C1.
SOLVENT EFFECT ON THE PHOTOCHEMICAL DEGRADATION OF MONO-AND DINITROPOLYCYCLIC AROMATIC HYDROCARBONS
Gernerique Stewart, Tracy Harris, Keonia Smith, Hongtao Yu
Jackson State University
Polycyclic Aromatic Hydrocarbons (PAHs) are a class of widely spread mutagenic and tumorigenic environmental contaminants. Nitro-polycyclic aromatic hydrocarbons (nPAHs) are derivatives of PAHs, and contain two or more fused aromatic rings made of carbon and hydrogen atoms. They are formed as a result of incomplete combustion of organic material. nPAHs are of primary concern because many are more carcinogenic than their parent PAHs, and also display a great degree of mutagencity. The photochemical degradation of 1-nitropyrene (1-NP), 2-nitrofluorene (2-NF), 2,7-dinitrofluorene (2,7-DNF), 3-nitrofluoranthene (3-NFA), 5-nitroacenapthene (5-NAN), 6-nitrochrysene (6-NC), and 9-nitroanthracene (9-NA) were studied. Each compound was dissolved in acetonitrile (CH3CN), acetonitrile and water, methylene chloride (CH2C12), chloroform (CHC13), N,N'-dimethylformamide (DMF), and DMF & H20 respectively, and diluted to a desired concentration. All nPAHs were irradiated by a UVA Lamp. The degradation of each nPAH was monitored using a CARY 300E UV-Vis spectrophotometer. The natural logarithm (Ln[x]) was taken of the absorbance for each time interval, and plotted Ln([A]0/[A]t) vs. Time. The linear equation Ln([A]0/[A]t) = kt, where [A]t is the height of the peak at time t, [A]0 is the height of the peak at time 0, k is the rate constant, and t is the irradiation time, was used to determine k. The half-life (t1/2) of each sample was determined by using the equation t1/2 = 0.693/k.
9:00 THIOL-ENE MICROEMULSIONS--NOVEL POLYMERS
Jolanta Marszalek, John Pojman, Charles Hoyle
The University of Southern Mississippi
Novel polymeric materials have been produced through photo-polymerization of a thiol-ene based reverse microemulsion. Through the polymerization of the organic phase of the reverse microemulsion, it is possible to prepare hydrophobic polymer materials that have an aqueous phase dispersed throughout. We are greatly interested in understanding polymerization-induced aqueous phase aggregation in these systems. The photopolymerization of the 1,3-haxanedithiol/pentaerythitolallyl ether microemulsion induced crystallization of the surfactant AOT leading to white films. Films immediately after polymerization contained 5.7% of water, 17 % of the surfactant and 77 % of the monomer mixture as determined through TGA analysis. After exposure to open atmosphere for extended time there was only 1.7 % of water left, which was strongly bonded to the surfactant. The water loss occurred within the first 20 minutes of the exposure to the open atmosphere. The thiol-ene microemulsion had a 48 hour shelf life before spontaneous polymerization occurred. In conclusion novel polymeric films were produced through photopolymerization of thiol-ene based microemulsion. Formed films contain the same amount of water as the microemulsion they are formed from. Crystallization of surfactant causes the films to have white color, that is persistent after the water leaves the film.
9:15 STUDY OF THE BEHAVIOR OF MISCIBLE AND PARTIALLY MISCIBLE SYSTEMS USING SPINNING DROP TENSIOMETRY
Gloria Viner, John Pojman
The University of Southern Mississippi
We used spinning drop tensiometry to measure the effective interfacial tension between miscible and partially miscible systems. We also observed similarities in behavior between different types of miscible systems. For example, a system with an upper critical solution temperature (UCST), such as isobutyric acid (IBA) and water, had a sharp concentration gradient as did a system with a lower critical solution temperature, such as triethylamine and water. There were also differences between miscible and partially systems. For example, though a system such as IBA/water had a sharp concentration gradient, a different type of miscible system, dodecyl acrylate-poly(dodecyl acrylate), did not have a sharp concentration gradient. We also observed the effect of rotational forces on the behavior of miscible systems.
9:30 INTERACTIONS BETWEEN SULFUR CONTAINING AMINO ACIDS AND PERFLUORINATED FATTY ACIDS
Tiffani Holmes (1), Jacek Doskocz (2), Terrance Wright (1), Jerzy Leszczynski (1), Glake Hill (1)
(1) Jackson State University, (2) Wroclaw University of Technology, Poland
The interaction of perfluorooctanoic acid (PFOA) with the amino acids cysteine and methionine was investigated using Density Functional Theory. Previous studies suggest that the peroxisome proliferator chemical, perfluorooctanoic acid, is circulated throughout the body by way of sulfur containing amino acids. We present conformational analysis of interactions of perfluorooctanoic acid with the sulfur containing amino acids which occur by way of hydrogen bonding where the hydrogen of the sulfhydryl group interacts with the carbonyl oxygen, and the amino nitrogen forms a hydrogen bond with the hydrogen of the -OH group of the fluorinated alkyl. We also show in our structures a recently characterized weak nonbonded interaction between divalent sulfur and a main chain carbonyl oxygen in proteins. B3LYP calculated interaction energies predict low energy conformations for complex systems of perfluorinated fatty acid interactions with cysteine, methionine, and tripeptides consisting of one of either sulfur containing amino acid with glycine end sites.
9:45 THEORETICAL COMPARISON OF PARATHION AND PARAOXON FOR THE DISCERNMENT OF ACETYLCHOLINESTERASE-PHOSHOROTHIONATE/ORGANOPHOSPHATE INHIBITION IN MAMMALS
Jason Ford-Green, Devashis Majumdar, Jerzy Leszczynski
Jackson State University
Theoretical conformational analyses have been carried out on the neurotoxicant metabolite paraoxon. This compound is the more toxic form of its indigenous yet still highly potent pesticide parathion (O,O-diethyl O-(4-Nitrophenyl) phosphorothioate). Studies were carried out at the density functional (DFT) B3LYP/6-31G (d,p) level of theory. The main pesticide activity is through the inhibition of the enzyme acetylcholinesterase (AChE). Six different low-energy conformers have been found for paraoxon at the B3LYP/6-31G (d,p) level of theory. The lowest low-energy conformer was found to exist in the te (175.38, 148.46) conformation, compared to the tg (176.4, 35.3) lowest low-energy conformer for parathion, illustrating that the OP nitroaromatic moiety positioning is conserved in the AChE active site. Hydration effects have also been studied at the DFT level using the polarized continuum model with a conductor-like screening reaction field (COSMO) approach for assessment of non-equilibrium energetic differentiation. The six low-energy conformers of paraoxon show more energetic favorability towards water solubility, as compared to the more hydrophobic nature of parathion. This alludes to the possibility of a more persistent systemic inhibition level. The Gibbs free energy distribution along the torsional angles bonded to the pentavalent phosphorus center relay that the paraoxon conformers require less free energy input at each low-energy conformation for flexibility.
10:15 INFLUENCE OF NON-TARGET WATER CONSTITUENTS ON THE VISIBLE-LIGHT MEDIATED TIO2 PHOTOCATALYTIC OXIDATION OF CIPROFLOXACIN
Kelseia Blair (1), Tias Paul (1), Timm Strathmann (1)
(1) University of Illinois, (2) Alcorn State University
This study is examining the effects that non-target water constituents, such as natural organic matter, have on the visible-light-mediated TiO2 photocatalytic degradation of the fluoroquinolone antibacterial agent ciprofloxacin. Experiments are designed to address the following questions: 1) Do natural organic and inorganic chemical constituents present in natural water affect the photocatalytic treatment of ciprofloxacin? And 2) Does their presence slow down, accelerate, or have no effect on the reaction? Answering these questions will help us to better understand how effective these treatment processes will be when treating source waters with different properties. Individual non-target water constituents that will be examined include natural organic matter, bicarbonate, nitrite, chloride, sodium, calcium, and phosphate ions. All experiments will be conducted at pH 3 with 0.5g/L TiO2 (anatase, Hombikat UV100) using light 1>400nm. I anticipate that my experiments will show that ciprofloxacin will be selectively treated in the presence of most constituents, but that the reaction will slow down in the presence of a small number of constituents.
10:30 PHOTOCHEMICAL REACTION OF A YE PRECURSOR 4-CHLORO-1,2-PHENYLENEDIAMINE AND ITS ASSOCIATED MUTAGENIC EFFECTS
Shuguang Wang, Charity Mosely, Gernerique Stewart, Hongtao Yu
Jackson State University
4-Chloro-1,2-phenylenediamine (4-Cl-o-PDA) is an aromatic diamine used as a precursor for manufacture of hair dyes and dyes of other purposes. 4-Cl-o-PDA has been found to be photomutagenic in bacteria when concurrently exposed to simulated sunlight irradiation. It is anticipated that the photochemical reaction and the associated reactive species generated are responsible for the photomutagenicity. Irradiation of 4-Cl-o-PDA by either outdoor sunlight or indoor lamp, one main photoproduct appeared and it was found to be 2,3-diamino-7-chlorophenazine, a dimerized product through the excited state reaction of 4-Cl-o-PDA in the presence of oxygen. The isolated yield of 13% for 2,3-diamino-7-chlorophenazine is far better than the oxidation reaction of 4-Cl-o-PDA by H202 and may therefore be used as a synthetic method. The half lives of transformation for 4-Cl-o-PDA in water (100 ?M) are 39 min or 62 min, respectively, when exposed to sunlight or a 300 W Xenon lamp. The photomutagenicity of 4-Cl-o-PDA and its photoproduct were tested in Salmonella typhimurium TA 102. Under the same conditions, both compounds are photomutagenic. In addition, 2,3-diamino-7-chlorophenazine is both phototoxic and mutagenic.
10:45 OPTIMIZATION AND REACTION KINETICS OF THE PRODUCTION OF BIODIESEL FROM CASTOR OIL
Scott Crymble, Rafael Hernandez, Todd French, Earl Alley
Mississippi State University
Ricinus communis, commonly known as the castor plant, has been cultivated for millennia as a source of oil for lamps and other applications. The seeds of the castor plant contain 35% to 55% oil. The major fatty acid component of castor oil is ricinoleic acid, which comprises 90% of the fatty acid profile. Ricinoleic acid is a monounsaturated, 18-carbon fatty acid with a hydroxyl functional group at C-12. This hydroxyl group causes castor oil to be highly polar, simplifying the mixing of the oil with methanol for the biodiesel reaction. Castor oil is more viscous than typical oils, which poses problems in the resulting biodiesel. A study of the esterification reaction kinetics of converting the castor oil into biodiesel was performed to determine reaction kinetics. This information can be used to engineer a biodiesel production facility with castor oil as a feedstock. Factors considered in the kinetics study included reaction temperature, catalyst concentration, ratio of methanol to oil, and reaction time. The resulting biodiesel and blends of castor biodiesel with other biodiesels (e.g., soy bean oil) were tested for compliance with appropriate ASTM standards. Production of biodiesel from castor oil would provide two benefits: (1) a source of oil that does not compete with the food supply, and (2) reduce the US dependency on foreign oil by providing a domestic alternative to petroleum diesel.
11:00 VIBRONIC INTENSITIES IN MOLECULAR SPECTRA, PART 1. THE THEORETICAL FOUNDATION
Dorothy M. Wood (1), Sean P. McGlynn (2)
(1) Jackson State University, (2) Louisiana State University
The ultimate objective of this work is the use of the vibronic intensity distributions in molecular spectra to determine the bond lengths of molecules in excited electronic states without having to evaluate Franck-Condon integrals (FCI.) We have achieved a novel system of mappings (FCM) by charting the exact FCI expressions. The FCIs, traditionally solved numerically, yield the vibronic intensity distribution in an electronic transition. The novel FCI equations presented here confirm the validity of that premise and, moreover, provide a direct source for bond lengths, novel details caused by slight variances in bond lengths, alternations of intensities at short bond lengths, clarifications for what otherwise might be thought of as background in an intensity distribution and even some reassignments of electronic transitions. The work presented here, while largely engrossed with theoretical foundations, will also present an illustrative, practical interpretation.
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|Publication:||Journal of the Mississippi Academy of Sciences|
|Date:||Jan 1, 2008|
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|Next Article:||Ecology and evolutionary biology.|