Home About us Contact | |||
Functional Computations (functional + computation)
Kinds of Functional Computations Selected AbstractsGas-phase acidity of proline from density functional computationsINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 2 2001T. Marino Abstract Density functional computations using the B3LYP hybrid potential coupled with the extended 6-311++G** basis set were performed to evaluate gas-phase acidity of proline ,-amino acid. The computed value of gas-phase acidity is 1403.8 kJ/mol in good agreement with the experimental counterpart (1395.0±13.8 kJ/mol) and is referred to the deprotonated species deriving from the first relative minimum of neutral proline characterized by the exo ring conformation with the carboxyl group in cis position. The most stable neutral proline isomer gives rise to a species for which the gas-phase acidity value (1384.5 kJ/mol) is also close to the experimental data. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 264,268, 2001 [source] Perfect planar tetracoordinate carbon in neutral unsaturated hydrocarbon cages: A new strategy utilizing three-dimensional electron delocalizationJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 13 2009Yang Wang Abstract A new series of unsaturated pure and boron-substituted hydrocarbons containing a perfect planar tetracoordinate carbon (ptC) have been proposed by performing density functional computations. The ptC is effectively stabilized through three-dimensional delocalization of ptC's lone pair into ,-conjugated systems, by utilizing a new strategy opening a brand new way of designing ptC structures. Compared to previously proposed ptC-containing hydrocarbon cage compound, a neutral hydrocarbon designed here might be a more viable target for synthetic attempts. © 2009 Wiley Periodicals, Inc. J Comput Chem 2009 [source] Density functional computations of proton affinity and gas-phase basicity of proline.JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 2 2002E. Tocci, M. Toscano., N. Russo, T. Marino The original article to which this Erratum refers was published in Journal of Mass Spectrometry36(3) 2001, 301,305 [source] Vibrational spectroscopy investigation using density functional theory on 7-chloro-3-methyl-2H-1,2,4- benzothiadiazine 1,1-dioxideJOURNAL OF RAMAN SPECTROSCOPY, Issue 6 2009S. Seshadri Abstract The solid phase Fourier transform infrared (FTIR) and Fourier transform (FT) Raman spectral analysis of 7-chloro-3-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide (diazoxide), an antihypertensive agent was carried out along with density functional computations. The optimized geometry, wavenumber and intensity of the vibrational bands of diazoxide were obtained by DFT-B3LYP level of theory with complete relaxation in the potential energy surface using 6-31G(d,p) basis set. A complete vibrational assignment aided by the theoretical harmonic frequency analysis has been proposed. The harmonic vibrational wavenumbers calculated have been compared with experimental FTIR and FT Raman spectra. The observed and the calculated wavenumbers are found to be in good agreement. The experimental spectra coincide satisfactorily with those of calculated spectra. Copyright © 2009 John Wiley & Sons, Ltd. [source] Density functional computations of 99Ru chemical shifts: relativistic effects, influence of the density functional, and study of solvent effects on fac,[Ru(CO)3I3],MAGNETIC RESONANCE IN CHEMISTRY, Issue 11 2006Jochen Autschbach Abstract Solvent effects on the 99Ru NMR chemical shift of the complex fac,[Ru(CO)3I3], are investigated computationally using density functional theory. Further, benchmark calculations of the 99Ru shift for a set of ten Ru complexes have been performed in order to calibrate the computational model and to determine the importance of relativistic effects on the 99Ru nuclear magnetic shielding and on the chemical shift. A computational model for fac,[Ru(CO)3I3], that includes both explicit solvent molecules and a continuum model is shown to yield the best agreement with experiment. Relativistic corrections are shown to be of minor importance for determining 99Ru chemical shifts. On the other hand, the nature of the density functional is of importance. In agreement with literature data for ligand trends of 99Ru chemical shifts, the chemical shift range for different solvents is also best reproduced by a hybrid functional. Copyright © 2006 John Wiley & Sons, Ltd. [source] |