heterogeneous catalytic hydrogenation of cyclohexene, catalyzed by pt/a1203, was carried out in thirteenvarious solvents (four alcoholic solvents, six aprotic polar solvents and three non polar solvents) at 25 °c.single-parameter correlations of logk vs. normalized polarity parameter (etn), hydrogen-bond acceptorbasicity (p), hydrogen-bond donor acidity (a) and dipolarity/polarizibility (it*) d...

dft-gga method of perdew-burke-ernzerhof (pbe) is used with aug-cc-pvtz, 6-311++g**, and def2-tzvp large basis sets to study the hydrogen bond interactions between oxygen lone pair as a donor electron with hydrogen atom connected to the aniline’s nitrogen as an electron acceptor (h2o···hnh-ph), and nitrogen lone pair with hydrogen of water molecule (ph-h2n···hoh), both in the gas phase. in some...

DFT-GGA method of Perdew-Burke-Ernzerhof (PBE) is used with aug-cc-PVTZ, 6-311++G**, and Def2-TZVP large basis sets to study the hydrogen bond interactions between oxygen lone pair as a donor electron with hydrogen atom connected to the aniline’s nitrogen as an electron acceptor (H2O···HNH-Ph), and nitrogen lone pair with hydrogen of water molecule (Ph-H2N···HOH...

objective: the aim of this in vitrostudy was to evaluate the effect of the type of solvent in silane solution on microtensile bond strength of fiber posts to composite resin cores af-ter application of 24% hydrogen peroxide. materials and methods: eighteen white fiber posts, immersed in 24% hydrogen peroxide were divided into three groups (n=6). in the group a post surfaces were silanized with ...

a fragment of histidine rich protein ii (hrp ii 215-236) was investigated by 14n and 17o electric field gradient, efg, tensor calculations using dft. this study is intended to explore the differences between 310-helix and α-helix of hrpii both in the gas phase and in solution. to achieve the aims, the 17o and 14n nqr parameters of a fragment of hrpii (215-236) for both structures are calculated...

The solvatochromism of fluoresceine and its derivatives was studied in solvents of different Hydrogen Bond Donor (HBD), Hydrogen Bond Acceptor (HBA), Donor Number (DN) and Acceptor Number (AN) by their UV-Vis spectra. Results showed that position, intensity and shape of absorption bands change with type of solvent. These changes can be rationalized by solvatochromic parameters such as ...

the nmr spectra of azo dyes, 5-arylazobarbituric (5a-g), 5-arylazo-1,3-dimethylbarbituric(6a-g) and 5-arylazothiobarbituric acids (7a-g) were studied in dmso-d6 in differentconcentrations. an intramolecular hydrogen bond was observed and indicating that thehydrazone forms is mostly predominant. the peak of the hydrazone proton was severelybroadened and its chemical shift appeared at down field ...