Chemistry Commons^™

Peptide Bond Formation Via Glycine Condensation In The Gas Phase, Eric Van Dornshuld, Robert A. Vergenz, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

Four unique gas phase mechanisms for peptide bond formation between two glycine molecules have been mapped out with quantum mechanical electronic structure methods. Both concerted and stepwise mechanisms, each leading to a cis and trans glycylglycine product (four mechanisms total), were examined with the B3LYP and MP2 methods and Gaussian atomic orbital basis sets as large as aug-cc-pVTZ. Electronic energies of the stationary points along the reaction pathways were also computed with explicitly correlated MP2-F12 and CCSD(T)-F12 methods. The CCSD(T)-F12 computations indicate that the electronic barriers to peptide bond formation are similar for all four mechanisms (ca. 32-39 kcal mol-1 …

Isolation And Screening Of Microalgae From Natural Habitats In The Midwestern United States Of America For Biomass And Biodiesel Sources, Keesoo Lee, Megan L. Eisterhold, Fabio Rindi, Swaminathan Palanisami, Paul Ki-Souk Nam

Chemistry Faculty Research & Creative Works

Native species of microalgae were isolated from natural water bodies in the Midwestern United States of America and were screened for the ultimate goal of mass cultivation in Missouri and the surrounding states, and for their potential as biomass and biodiesel sources. A number of different nutrient media recipes were utilized to isolate the maximum number of colonies from each field samples. These nutrient recipes were modified in order to optimize the isolation and growth dynamics of specific colonies. All of the isolates were categorized based on the morphological appearance of the culture and the microscopic cellular appearance of the …

Characterizing The B-P Stretching Vibration In Phosphorus-Substituted Phosphine Boranes, Dana N. Reinemann, Gregory S. Tschumper, Nathan I. Hammer

Chemistry Faculty Research & Creative Works

The experimental Raman spectra of three phosphorus-substituted phosphine boranes with bulky hydrocarbon substituents are presented and compared to the results of electronic structure computations by using the M06-2X method and the 6-311G(2df,-2pd) basis set. Total-energy distributions (TEDs) are calculated to describe the degree of mixing of the dative-bond stretching vibration with other simple internal coordinates. This level of theory is found to accurately reproduce the B-P stretching frequency in all three crystalline solids. The Raman spectra of five smaller B-P-containing molecules, including BH₃PH₃, are also simulated at this level of theory and compared to previous experimental …

Fabrication Of Multifunctional Ferromagnetic Au₃Pd-Cose Nanoparticles, Wipula P. Liyanage, Sukhada Mishra, Kai Song, Manashi Nath

Chemistry Faculty Research & Creative Works

We have synthesized multifunctional anisotropic Au₃Pd-CoSe nanoparticles on Si substrate through a catalyst aided chemical vapour deposition technique. the technique utilized volatile cobalt acetylacetonate and elemental selenium as precursors while sputter coated Au-Pd (3:2) film acted as a catalyst. the typical growth conditions led to clear segregation of the hetero-compositions (i.e. Au₃Pd and CoSe) in the product nanostructures thereby preserving the functionality of both the phases. the degree of crystallinity of the individual phases in the composite nanostructure was fairly high. the bifunctional nanoparticles show soft ferromagnetic behaviour at room temperature and optical activity making them …

Homogeneous And Heterogeneous Noncovalent Dimers Of Formaldehyde And Thioformaldehyde: Structures, Energetics, And Vibrational Frequencies, Eric Van Dornshuld, Christina M. Holy, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

This work provides the first characterization of five stationary points of the homogeneous thioformaldehyde dimer, (CH₂S)₂, and seven stationary points of the heterogeneous formaldehyde/thioformaldehyde dimer, CH₂O/CH₂S, with correlated ab initio electronic structure methods. Full geometry optimizations and corresponding harmonic vibrational frequencies were computed with second-order Møller-Plesset perturbation theory (MP2) and 13 different density functionals in conjunction with triple-ζ basis sets augmented with diffuse and multiple sets of polarization functions. The MP2 results indicate that the three stationary points of (CH₂S)₂ and four of CH₂O/CH₂S are …

Epigenetic Modification, Dehydration, And Molecular Crowding Effects On The Thermodynamics Of I-Motif Structure Formation From C-Rich Dna, Yogini P. Bhavsar-Jog, Eric Van Dornshuld, Tracy A. Brooks, Gregory S. Tschumper, Randy M. Wadkins

Chemistry Faculty Research & Creative Works

DNA sequences with the potential to form secondary structures such as i-motifs (iMs) and G-quadruplexes (G4s) are abundant in the promoters of several oncogenes and, in some instances, are known to regulate gene expression. Recently, iM-forming DNA strands have also been employed as functional units in nanodevices, ranging from drug delivery systems to nanocircuitry. To understand both the mechanism of gene regulation by iMs and how to use them more efficiently in nanotechnological applications, it is essential to have a thorough knowledge of factors that govern their conformational states and stabilities. Most of the prior work to characterize the conformational …

Characterization Of The Potential Energy Surfaces Of Two Small But Challenging Noncovalent Dimers: P2)2 And (Pccp) 2, Eric Van Dornshuld, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

This work characterizes eight stationary points of the P2 dimer and six stationary points of the PCCP dimer, including a newly identified minimum on both potential energy surfaces. Full geometry optimizations and corresponding harmonic vibrational frequencies were computed with the second-order Møller-Plesset (MP2) electronic structure method and six different basis sets: aug-cc-pVXZ, aug-cc-pV(X+d)Z, and aug-cc-pCVXZ where X = T, Q. A new L-shaped structure with C₂ symmetry is the only minimum for the P₂ dimer at the MP2 level of theory with these basis sets. The previously reported parallel-slipped structure with C_2h symmetry and a newly identified …

Computational Study Of The Rovibrational Spectrum Of Co₂-Cs₂, James Corgan Brown, Xiao-Gang Wang, Tucker Carrington Jr., Garry S. Grubbs, Richard Dawes

Chemistry Faculty Research & Creative Works

A new intermolecular potential energy surface, rovibrational transition frequencies, and line strengths are computed for CO₂-CS₂. the potential is made by fitting energies obtained from explicitly correlated coupled-cluster calculations using an interpolating moving least squares method. the rovibrational Schrödinger equation is solved with a symmetry-adapted Lanczos algorithm and an uncoupled product basis set. All four intermolecular coordinates are included in the calculation. in agreement with previous experiments, the global minimum of the potential energy surface (PES) is cross shaped. the PES also has slipped-parallel minima. Rovibrational wavefunctions are localized in the cross minima and the slipped-parallel …

Specific Intracellular Uptake Of Herceptin-Conjugated Cdse/Zns Quantum Dots Into Breast Cancer Cells, Seung-Jin Han, Pierson Rathinaraj, Soo-Young Park, Young-Kyoo Kim, Joon Hyung Lee, Inn-Kyu Kang, Jong-Sik Moon, Jeffrey G. Winiarz

Chemistry Faculty Research & Creative Works

Herceptin, a typical monoclonal antibody, was immobilized on the surface of CdSe/ZnS core-shell quantum dots (QDs) to enhance their specific interactions with breast cancer cells (SK-BR3). the mean size of the core-shell quantum dots (28 nm), as determined by dynamic light scattering, increased to 86 nm after herceptin immobilization. the in vitro cell culture experiment showed that the keratin forming cancer cells (KB) proliferated well in the presence of herceptin-conjugated QDs (QD-Her, 5 nmol/mL), whereas most of the breast cancer cells (SK-BR3) had died. to clarify the mechanism of cell death, the interaction of SK-BR3 cells with QD-Her was examined …

Synthesis, Optical Properties And Photovoltaic Applications Of Hybrid Rod-Coil Diblock Copolymers With Coordinatively Attached Cdse Nanocrystals, Shaohua Li, Yong Li, Clarissa A. Wisner, Lu Jin, Nicholas Leventis, Zhonghua Peng

Chemistry Faculty Research & Creative Works

The performance of hybrid solar cells based on conjugated polymers and nanostructured inorganic semiconductors is often limited by the poor interfacial interaction and the lack of controlled phase separation. Improvements are being made by building intimate contact between the two components through coordinative linkages. in this contribution, three rod-coil diblock copolymers (DCPs) of the modified poly(3-hexylthiophene)-polystyrene (P3HT-PS) type with different phosphorus-containing functional groups for binding to inorganic nanoparticles are reported. Their corresponding P3HT-PS-CdSe hybrid DCPs (HDCPs) were prepared by ligand-exchange with chemically prepared CdSe nanocrystals. the three DCPs have different size disparity between the rod and coil blocks, where the …

Antioxidant Potential Of Sutherlandia Frutescens And Its Protective Effects Against Oxidative Stress In Various Cell Cultures, Shakila Tobwala, Weili Fan, Connor J. Hines, William Robert Folk, Nuran Ercal

Chemistry Faculty Research & Creative Works

Sutherlandia frutescens (L.) R.Br. (SF) is a South African plant that is widely used to treat stress, infections, cancer, and chronic diseases, many of which involve oxidative stress. The aim of the study was to quantitatively assess the antioxidant potential of SF extracts in cell-free system as well as in cell lines. Dried SF vegetative parts were extracted using six different solvents, and the extracts were assessed for total phenolic and flavonoid contents, total reducing power, iron chelating capacity, and free radical scavenging power, including, scavenging of hydroxyl radicals, superoxide anions, nitric oxide, and hydrogen peroxide. We further investigated the …

Ru/C: A Simple Heterogeneous Catalyst For The Amination Of Azoles Under Ligand Free Conditions, K. Harsha Vardhan Reddy, B. S.P. Anil Kumar, V. Prakash Reddy, R. Uday Kumar, Y. V.D. Nageswar

Chemistry Faculty Research & Creative Works

A ligand free Ru/C-catalyzed amination of 2-halo azoles with a broad scope of aminating reagents has been developed. A variety of 2-aminoazole derivatives were synthesized in moderate to good yields by utilizing this protocol. The methodology is operationally simple and not sensitive to air and moisture. It provides potentially useful products by using an inexpensive and recyclable catalytic system under ligand free conditions without significant loss of its catalytic activity up to four cycles. This journal is

The Role Of Potential Antioxidant In Medicinal Drug-Induced Oxidative Stress, Weili Fan

Doctoral Dissertations

"Most medicinal drugs have adverse effects. Among the most commonly used of these drugs are several types, known as "oxidative drugs". These are believed to cause adverse effects that induce oxidative stress, an imbalance of generation and detoxification of reactive oxygen species. So it is a reasonable assumption that the antioxidant might alleviate the toxicity induced by these drugs. N-acetylcysteine (NAC), a synthetic thiol, is a free-radical scavenger and a precursor of glutathione (the main endogenous antioxidant). However, the negative charge of NAC at physiological pH limits its bioavailability. N-acetylcysteineamide (NACA) is neutral in charge and is believed to have …

Gold-Magnetite Nanoparticle-Biomolecule Conjugates: Synthesis, Properties And Toxicity Studies, Akshay Pariti

Masters Theses

"This thesis study focuses on synthesizing and characterizing gold-magnetite optically active magnetic nanoparticle and its conjugation with biomolecules for biomedical applications, especially magnetic fluid hyperthermia treatment for cancerous tissue. Gold nanoparticles have already displayed their potential in the biomedical field. They exhibit excellent optical properties and possess strong surface chemistry which renders them suitable for various biomolecule attachments. Studies have showed gold nanoparticles to be a perfect biocompatible vector. However, clinical trials for gold mediated drug delivery and treatment studied in rat models identified some problems. Of these problems, the low retention time in bloodstream and inability to maneuver externally …

Wavefunction Methods For The Accurate Characterization Of Water Clusters, J. Coleman Howard, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

Although the first ab initio Hartree-Fock computations of the water dimer were reported more than four decades ago, the detailed characterization of water clusters with sophisticated electronic structure techniques remains an important and vibrant area of research. The field of computational quantum chemistry has made significant advances since those pioneering studies. Geometry optimizations of the water dimer can now be carried out at the CCSDTQ level, and CCSD(T) energies can be computed with the aug-cc-pVTZ basis for clusters as large as (H₂O)₁₇. Some of these high-level studies are starting to reveal that the electronic structure is …

Investigation Of Fluids Flow Behavior In Nano-Scale Channels By Using Optic Imaging System, Qihua Wu

Doctoral Dissertations

"Tight gas and shale gas reservoirs are characterized to have small pores with diameters in nanometer (nm) range. The physics of fluid flow in nanopores is poorly understood. Knowing the fluid flow behavior in the nano-range channels is of major importance for stimulation design, gas production optimization and calculations of the relative permeability of gas in tight shale gas systems. In this work, a lab-on-chip approach for direct visualization of the fluid flow behavior in nano-scale channels was developed using an advanced epi-fluorescence microscopy method combined with a nano-fluidic chip. The nanofluidic chips with different dimensions were designed and fabricated. …

Manufacturing Of Vegetable Oils-Based Epoxy And Composites For Structural Applications, Rongpeng Wang

Doctoral Dissertations

"Epoxidized vegetable oil (EVO) is one of the largest industrial applications of vegetable oils (VOs) and is widely used as a plasticizer and as a synthetic intermediate for polyol or unsaturated polyester. However, the utility of EVO as monomer for high performance epoxy thermoset polymer is limited by its reactivity and by the resulting physical properties. Herein, VO-based epoxy monomers, i.e., glycidyl esters of epoxidized fatty acids derived from soybean oil (EGS) or linseed oil (EGL), have been synthesized and were benchmarked against commercial available diglycidyl ether of bisphenol A (DGEBA) and also epoxidized soybean oil (ESO) controls. EGS and …

Synthesis And Properties Of Transition-Metal Arsenide Nanostructures: From Superparamagnetism To Superconductivity, Prachi Desai

Doctoral Dissertations

"This dissertation study focuses on developing new protocols for synthesis of nanostructured transition-metal pnictides including superconducting LiFeAs and studying their structure- property relationship. Nanostructured materials are known to differ in properties compared to their bulk counterparts owing to enhanced surface area and increased packing efficiency in devices. Synthetic chemistry skills and nanofabrication techniques like wet chemistry, electrodeposition, solvothermal, hydrothermal and lithography, are extremely useful for creating nanostructures of these functional materials. This is a challenging task simply because maintaining the phase composition same as that of the bulk material along with achieving nanostructures (nanoparticles, nanowires, nanopillars etc.) simultaneously is not …

Part I: In-Situ Fluorometric Quantification Of Microalgal Neutral Lipids Part Ii: Thermal Degradation Behavior Of Investment Casting Polymer Patterns, Hongfang Zhao

Doctoral Dissertations

"Research described in this dissertation covers two topics. Part-I is focused on in-situ determination of neutral lipid content of microalgae using a lipophilic fluorescent dye. The traditional Nile red stain-based method for detecting microalgal intracellular lipids is limited due to varying composition and thickness of rigid cell walls. In this study, the addition of dilute acid and heating of solution, were found to greatly enhance staining efficiency of Nile red for microalgal species evaluated. Oil-in-water (O/W) microemulsion stabilized by a non-ionic surfactant was employed as a pseudo-standard that mimics lipid-bearing microalgal cells suspended in water. The average neutral lipid contents …

Semiconductor Nanocrystals For Novel Optical Applications, Jong-Sik Moon

Doctoral Dissertations

“Inspired by the promise of enhanced spectral response, photorefractive polymeric composites photosensitized with semiconductor nanocrystals have emerged as an important class of materials. Here, we report on the photosensitization of photorefractive polymeric composites at visible wavelengths through the inclusion of narrow band-gap semiconductor nanocrystals composed of PbS. Through this approach, internal diffraction efficiencies in excess of 82%, two-beam-coupling gain coefficients in excess of 211 cm^-1, and response times 34 ms have been observed, representing some of the best figures-of-merit reported on this class of materials. In addition to providing efficient photosensitization, however, extensive studies of these hybrid composites …

Aerogels As Diverse Nanomaterials, Abhishek N. Bang

Doctoral Dissertations

"Aerogels are 3-D light-weight nanoporous materials pursued for their low thermal conductivity, low dielectric constant and high acoustic attenuation. Those exceptional macroscopic properties of aerogels are dependent on the chemical nature of nanoparticles, complex hierarchical solid skeletal framework and porosity. Also, the free space can become host for functional guests such as pharmaceuticals. In chapter I, we investigated randomly mesoporous bio-compatible polymer-crosslinked dysprosia aerogels as drug delivery vehicles and demonstrated storage and release of drugs under physiological conditions. Comparative study with ordered and randomly mesoporous silica showed high drug uptake and slower release rate for random nanostructures (silica or dysprosia) …

Graphite Aerogels And The Formation Mechanism Of Unusual Micron-Sized Rod And Helical Structures, Clarissa Ann Wisner

Doctoral Dissertations

"Pyrolysis at 800 ºC under argon has shown that polyimide (PI), polyacrylonitrile (PAN), polydicyclopentadiene (DCPD) and polybenzoxazine (PBO) aerogels are all viable alternatives to traditional resorcinol-formaldehyde (RF) aerogels as precursors to amorphous carbon aerogels. Subsequent high temperature pyrolysis at 2300 ºC of such carbon aerogels under helium has shown that amorphous carbon from PI and PBO yields the highest degree of graphitization, whereas from RF aerogels yields the lowest.

Those two types of graphite aerogels include also a high concentration of micron-size columnar and helical (screw-like) structures, whose formation is favored by macroporosity and high nitrogen retention in the 800 …

C4a-Hydroperoxyflavin Formation In N -Hydroxylating Flavin Monooxygenases Is Mediated By The 2′-Oh Of The Nicotinamide Ribose Of Nadp⁺, Reeder Robinson, Somayesadat Badieyan, Pablo Sobrado

Chemistry Faculty Research & Creative Works

Flavin-dependent monooxygenases must stabilize a C4a-hydroperoxyflavin intermediate to hydroxylate their respective substrates. Formation and decay of the C4a-hydroperoxyflavin were monitored under rapid reaction kinetic conditions in SidA, an N-hydroxylating monooxygenase involved in siderophore biosynthesis. Solvent kinetic isotope effect studies of flavin oxidation indicate that both hydrogen peroxide elimination and water elimination occur via abstraction of hydrogen from the N5 of the flavin. Kinetic isotope effect and density functional theory results are consistent with the transfer of a proton from the 2′-OH of the nicotinamide ribose of nicotinamide adenine dinucleotide phosphate (NADP+) to the C4a-peroxyflavin to form the C4a-hydroperoxyflavin. This represents …

Gfsa Encodes A Novel Galactofuranosyltransferase Involved In Biosynthesis Of Galactofuranose Antigen Of O-Glycan In Aspergillus Nidulans And Aspergillus Fumigatus, Yuji Komachi, Shintaro Hatakeyama, Haruka Motomatsu, Taiki Futagami, Karina Kizjakina, Pablo Sobrado, Keisuke Ekino, Kaoru Takegawa, Masatoshi Goto, Yoshiyuki Nomura, Takuji Oka

Chemistry Faculty Research & Creative Works

Summary: The cells wall of filamentous fungi in the genus Aspergillus has galactofuranose (Galf)-containing polysaccharides and glycoconjugates, including O-glycans, N-glycans, fungal-type galactomannan and glycosylinositolphosphoceramide, which are important for cell wall integrity. Here, we attempted to identify galactofuranosyltransferases that couple Galf monomers onto other wall components in Aspergillus nidulans. Using reverse-genetic and biochemical approaches, we identified that the AN8677 gene encoded a galactofuranosyltransferase, which we called GfsA, involved in Galf antigen biosynthesis. Disruption of gfsA reduced binding of β-Galf-specific antibody EB-A2 to O-glycosylated WscA protein and galactomannoproteins. The results of an in-vitroGalf antigen synthase assay revealed that GfsA has β1,5- or …

N-Body:Many-Body Qm:Qm Vibrational Frequencies: Application To Small Hydrogen-Bonded Clusters, J. Coleman Howard, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

We present an efficient method for reproducing CCSD(T) (i.e., the coupled-cluster method with single, double and perturbative connected triple excitations) optimized geometries and harmonic vibrational frequencies for molecular clusters with the N-body:Many-body QM:QM technique. In this work, all 1-body through N-body interactions are obtained from CCSD(T) computations, and the higher-order interactions are captured at the MP2 level. The linear expressions from the many-body expansion facilitate a straightforward evaluation of geometrical derivative properties (e.g., gradients and Hessians). For (H₂O)_n clusters (n = 3-7), optimized structures obtained with the 2-body:Many-body CCSD(T):MP2 method are virtually identical to CCSD(T) optimized geometries. …

Examination Of Tyrosine/Adenine Stacking Interactions In Protein Complexes, Kari L. Copeland, Samuel J. Pellock, James R. Cox, Mauricio L. Cafiero, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

The π-stacking interactions between tyrosine amino acid side chains and adenine-bearing ligands are examined. Crystalline protein structures from the protein data bank (PDB) exhibiting face-to-face tyrosine/adenine arrangements were used to construct 20 unique 4-methylphenol/N9-methyladenine (p-cresol/9MeA) model systems. Full geometry optimization of the 20 crystal structures with the M06-2X density functional theory method identified 11 unique low-energy conformations. CCSD(T) complete basis set (CBS) limit interaction energies were estimated for all of the structures to determine the magnitude of the interaction between the two ring systems. CCSD(T) computations with double-ζ basis sets (e.g., 6-31G*(0.25) and aug-cc-pVDZ) indicate that the MP2 method overbinds …

Role Of Ser-257 In The Sliding Mechanism Of Nadp(H) In The Reaction Catalyzed By The Aspergillus Fumigatus Flavin-Dependent Ornithine N ⁵-Monooxygenase Sida, Carolyn Shirey, Somayesadat Badieyan, Pablo Sobrado

Chemistry Faculty Research & Creative Works

SidA (siderophore A) is a flavin-dependent N-hydroxylating monooxygenase that is essential for virulence in Aspergillus fumigatus. SidA catalyzes the NADPH- and oxygen-dependent formation of N5-hydroxyornithine. In this reaction, NADPH reduces the flavin, and the resulting NADP+ is the last product to be released. The presence of NADP+ is essential for activity, as it is required for stabilization of the C4a-hydroperoxyflavin, which is the hydroxylating species. As part of our efforts to determine the molecular details of the role of NADP(H) in catalysis, we targeted Ser-257 for site-directed mutagenesis and performed extensive characterization of the S257A enzyme. Using a combination of …

Substrate-Dependent Dynamics Of Udp-Galactopyranose Mutase: Implications For Drug Design, Leonardo Boechi, Cesar Augusto F. De Oliveira, Isabel Da Fonseca, Karina Kizjakina, Pablo Sobrado, John J. Tanner, J. Andrew Mccammon

Chemistry Faculty Research & Creative Works

Trypanosoma cruzi is the causative agent of Chagas disease, a neglected tropical disease that represents one of the major health challenges of the Latin American countries. Successful efforts were made during the last few decades to control the transmission of this disease, but there is still no treatment for the 10 million adults in the chronic phase of the disease. In T. cruzi, as well as in other pathogens, the flavoenzyme UDP-galactopyranose mutase (UGM) catalyzes the conversion of UDP-galactopyranose to UDP-galactofuranose, a precursor of the cell surface b-galactofuranose that is involved in the virulence of the pathogen. The fact that …

The Carriers Of The Interstellar Unidentified Infrared Emission Features: Constraints From The Interstellar C-H Stretching Features At 3.2-3.5 Μm, Xuejuan Yang, Rainer Glaser, Aigen Li, Jianxin Zhong

Chemistry Faculty Research & Creative Works

The unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm, commonly attributed to polycyclic aromatic hydrocarbon (PAH) molecules, have recently been ascribed to mixed aromatic/aliphatic organic nanoparticles. More recently, an upper limit of <9% was placed on the aliphatic fraction (i.e., the fraction of carbon atoms in aliphatic form) of the UIE carriers based on the observed intensities of the 3.4 μm and 3.3 μm emission features by attributing them to aliphatic and aromatic C-H stretching modes, respectively, and assuming A _3.4/A _3.3 ≈ 0.68 derived from a small set of aliphatic and aromatic compounds, where A _3.4 and A _3.3 are, respectively, the band strengths of the 3.4 μm aliphatic and 3.3 μm aromatic C-H bonds. To improve the estimate of the aliphatic fraction of the UIE carriers, here we analyze 35 UIE sources exhibiting both the 3.3 μm and …

Charge Transfer And Blue Shifting Of Vibrational Frequencies In A Hydrogen Bond Acceptor, Ashley M. Wright, Austin A. Howard, J. Coleman Howard, Gregory S. Tschumper, Nathan I. Hammer

Chemistry Faculty Research & Creative Works

A comprehensive Raman spectroscopic/electronic structure study of hydrogen bonding by pyrimidine with eight different polar solvents is presented. Raman spectra of binary mixtures of pyrimidine with methanol and ethylene glycol are reported, and shifts in ν₁, ν₃, ν_6a, ν_6b, ν_8a, ν_8b, ν_9a, ν₁₅, ν_16a, and ν_16b are compared to earlier results obtained for water. Large shifts to higher vibrational energy, often referred to as blue shifts, are observed for ν₁, ν_6b, and ν_8b (by as much …