An Erbium(III) quaternary chelate, nitratebis(2,4-hexanedionate)mono(2,2-bipyridine) erbium(III), has been synthesized and its structure elucidated by X-ray diffraction. There are two independent lanthanide complexes in the asymmetric unit cell. The ligands coordinate the Er(III) in a square anti-prismatic geometry. In the theoretical part of this study, semi-empirical quantum chemistry methods...

The catalytic cycle for the serine protease α-chymotrypsin was investigated in an attempt to determine the suitability of using the semiempirical method PM7 in the program MOPAC for investigating enzyme-catalyzed reactions. All six classical intermediates were modeled using standard methods, and were characterized as stable minima on the potential energy surface. Using a modified saddle point o...

In this study, we theoretically investigated Methyl hydrazinecarbodithioate by quantum chemical calculations for geometry optimization, vibration frequencies, and electronic structure parameters. The geometry optimization by DFT, ab initio MP2 method and the frequency calculation by DFT method was performed at the highest available Pople style 6-311G++(3df,3pd) basis set level. The semi-emp...

In the present research, synthesis of new 2-(3-chlorobenzyl)-1H-benzimidazole derivatives bearing Nbenzylidene, 1,2,4-triazole and N-acylhydrazone moiety is investigated. These novel compounds have been tested for their antimicrobial effects against two of Gram-positive bacterial strains, namely Bacillus subtilis and Staphylococcus epidermidis, and four Gram-negative bacterial strains which wer...

The semiempirical orthogonalization-corrected OMx methods (OM1, OM2, and OM3) go beyond the standard MNDO model by including additional interactions in the electronic structure calculation. When augmented with empirical dispersion corrections, the resulting OMx-Dn approaches offer a fast and robust treatment of noncovalent interactions. Here we evaluate the performance of the OMx and OMx-Dn met...

Abstract In this study, we calculated the enthalpy (Δ H , kcal/mol), entropy (∆ S cal/K·mol) and free energy G kcal/mol) thermodynamic values of each molecule for forty-seven different solvent media according to semi-empirical quantum methods (PM7, PM6, PM6-DH2, RM1, PM3, AM1, MNDO) using MOPAC computer program. The theoretical pKa were by placing these in cycle. It was determined that triazole...

Abstract The structure of model compounds for the amphiphilic copolymer poly(diisobutylene‐ alt ‐maleic acid), DIBMA, is investigated with (gas phase) B3LYP/6‐31G** and PM7 calculations. It found that in monoprotonated state repeating unit strong (about 70 kJ mol −1 ) ionic hydrogen bonds are formed within succinate rings, which impart partial structural rigidity on backbone copolymer. Based li...