The series of methyl halides, CH(3)X (X = F, Cl, Br, and I), is prototypic for demonstrating the s.c. normal halogen dependence of light-atom nuclear magnetic resonance shielding constants in the presence of halogen atoms of varying electronegativity. We report a systematic experimental and first-principles theoretical study of the (13)C and (1)H shielding tensors in this series. The experiment...

in the present work, dft calculations are employed to obtain the optimized structures of 4-acyl pyrazolone tautomers (19 tautomers) using b3lyp/6-311++g** calculations. inaddition, molecular parameters, ir frequencies and relative energies are extracted for alltautomers. the existence of aromatic ring, keto tautomer (versus enol tautomer), n-h bond(versus c-h bond) and c=n double bond (versus n...

The solvation of infinitely dilute solutes in supercritical solvents is illustrated by integral equation calculations, according to a recently proposed molecularbased formalism that characterizes the solvent environment around individual species and connects it to the resulting macroscopic solvation behavior. The formalism is applied to the analysis of the solubility enhancement of nonelectroly...

The binding of myo-inositol hexasulfate to an N-terminal truncated 132-amino-acid human acidic fibroblast growth factor form was studied by isothermal titration calorimetry. The technique yields values for the enthalpy change and equilibrium constant, from which the Gibbs energy and entropy change can also be calculated. Experiments in different buffers and pH values show that the proton balanc...

Some aryl and heteroaryl azido compounds were synthesized from the reaction of corresponding fluoro and chloro compounds with sodium azide in DMF as solvent and under various reaction conditions especially ultrasonic irradiation. Reaction of aromatic and heteroaromatic azido compound with thioacetic acid in the presence of sodium hydrogen carbonate and in methanol as solvent led to the differen...

Plant metabolomic analysis has become an essential part of functional genomics and systems biology and requires effective extraction of both primary and secondary metabolites from plant cells. To establish an optimized extraction method for the NMR-based analysis, we used the seeds of mungbean (Vigna radiata cv. Elü no. 1) as a model and systematically investigated the dependence of the metabol...

We present a theoretical, site-specific, approach to predict protein subunit correlation times, as measured by NMR experiments of (1)H-(15)N nuclear Overhauser effect, spin-lattice relaxation, and spin-spin relaxation. Molecular dynamics simulations are input to our equation of motion for protein dynamics, which is solved analytically to produce the eigenvalues and the eigenvectors that specify...

Biosynthetic preparation and (19)F NMR experiments on uniformly 3-fluorotyrosine-labeled green fluorescent protein (GFP) are described. The (19)F NMR signals of all 10 fluorotyrosines are resolved in the protein spectrum with signals spread over 10 ppm. Each tyrosine in GFP was mutated in turn to phenylalanine. The spectra of the Tyr --> Phe mutants, in conjunction with relaxation data and resu...

In this research, Quantum-mechanical calculations were performed at the HF method with the 6-31+G*basis set and at the B3LYP method with the 6-31+G* basis set in the gas phase and five solvents such as water, DMSO, methanol, ethanol and dichloromethane at six temperatures. According to these theoretical results of IR, we extracted thermo chemical parameters such as enthalpy (∆H Kcal/mol), Gibbs...

A series of strong H-bonded complexes of trimethylglycine, also known as betaine, with acetic, chloroacetic, dichloroacetic, trifluoroacetic and hydrofluoric acids as well as the homo-conjugated cation of betaine with trifluoroacetate as the counteranion were investigated by low-temperature (120-160 K) liquid-state NMR spectroscopy using CDF(3)/CDF(2)Cl mixture as the solvent. The temperature d...