Several inconsistencies have been noted during recent systematic studies of the validity of additivity relationships (1-6) in the C chemical shifts of substituted pyridines. These showed that substantial errors could be introduced if care is not taken to use, for a given solvent, approximately the same concentration for all solutes; in our case this applied to monosubstituted and polysubstitute...

in this research at the first metoprolol drug and its fullerene derivative were optimized. natural bond orbital (nbo), nuclear indepndent chemical shift (nics) and finally ir calculations, for these compounds were carried out at the b3lyp/6-31g* quantum chemistry level. different parameters such as energy levels, the amount of chemical shift in different atoms, the amount of homo/lumo, chemical...

the n-(2-benzoyl-phenyl) oxalyl derivatives are important models for studying of three-centered intramolecular hydrogen bonding in organic molecules. the quantum theoretical calculations for two crystal structures of n-(2-benzoyl-phenyl) oxalyl (compounds i and ii) were performed by density functional theory (b3lyp method and 6-311+g* basis set). from the optimized structures, geometric paramet...

A new method for refinement of 3D molecular structures by geometry optimization is presented. Prerequisites are a force field and a very fast procedure for the calculation of chemical shifts in every step of optimization. To the energy, provided by the force field (COSMOS force field), a pseudoenergy, depending on the difference between experimental and calculated chemical shifts, is added. In ...

Sulforaphane, an isothiocyanate found in broccoli and other cruciferous vegetables. it is an antioxidantand anti-cancer agent, and reduces blood pressure, and also has anti-allergic Effects.In this article, six theoretical methods have been used for calculation of physical parameters insolforaphane and several similar compounds. We calculated physical parameters like atomic charges.energy (AE) ...

The molecular structure of Cyclophosphamide (N, N-bis(2-chloroethyl)-1,3,2-oxazaphosphinan-2-amine 2-oxide is the anti cancer drug and used to treat cancer and immune diseases) and SWCNTswere calculated by the B3LYP density functional model with 6-311G* basis set with Gaussian 09program. The nanotube used in this study, includes 120 C atoms (5, 5) type. The NBO analysisshowed there is a hyperco...