Author: eletronicospopular

Conformational equilibria for 5-Fluoro, 5-Chloro and 5-Bromo-trans-1,3-pentadiene: the effect of the halogen substituent. Abstract The results of ab initio SCF MO calculations at the Hartree–Fock (3–21G and 6–31G*) and DFT levels (B3LYP/6–31G*, B3LYP/6–311+G**) for 5-fluoro- (5FP), 5-chloro- (5ClP) and 5-bromo-trans -penta-1,3-diene (5BrP) molecules and vibrational spectra (Raman and FTIR) of the corresponding liquid phases are…

H/D and D/H exchange rates in alpha-cyclodextrin and alpha-cyclodextrin inclusion compounds: A Raman spectroscopic study. Abstract The H/D and D/H exchange rates of hydroxy groups in crystalline α-cyclodextrin (CD) exposed to H 2 O and D 2 O vapour, respectively, have been studied by monitoring the relative integrated Raman intensities of the O–H and O–D…

Evidence of dimerization through C-H…O interactions in liquid 4-methoxybenzaldehyde from Raman spectra and Ab initio calculations. Abstract The vibrational spectra of 4-methoxybenzaldehyde in the liquid phase show pairs of bands whose temperature- and solvent-dependent behaviour can hardly be interpreted only in terms of a cis-trans conformational equilibrium. In particular, the solvent and temperature-dependent intensities of…

Structure and Vibrational Frequencies of Vanadium(V) oligomers: an ab initio study using effective core potentials. Abstract Ab initio molecular geometries and vibrational frequencies of various isolated vanadate species (VO3−4, HVO2−4, H2VO−4, and V2O4−7) were calculated using different pseudopotentials. The relative merits of these were assessed by comparing the calculated molecular parameters with the corresponding values…

Ab initio SCF MO calculations on triaza and tetraaza cyclic amines. Abstract Molecular orbital ab initio calculations have been performed on some triaza and tetraaza cyclic amines aiming at the determination of their minimum energy geometries and of the relative conformational energies in different protonation states.The results clearly show two factors governing the conformational preferences…