SPECTRAL ANALYSIS of ACETYLCHOLINE HALIDES by DENSITY FUNCTIONAL THEORY CALCULATIONS

acetylcholine halide vibration DFT IR Raman NMR

INTERMOLECULAR HYDROGEN BONDING BETWEEN N-SUBSTITUTED CAPROAMIDES AND TETRAHYDROFURAN, КРИСТАЛЛИЧЕСКАЯ СТРУКТУРА И МАГНИТНЫЕ СВОЙСТВА БИОКТАЭДРИЧЕСКОГО КОМПЛЕКСА Cs3Nb2I9, ...

The comparison of their experimental and calculated IR, R and NMR spectra of the compounds has indicated that the spectra of three optimized minimum energy conformers can simultaneously exist in one experimental spectrum. <...> Thus, it was concluded that the compounds simultaneously exist in three conformations in the ground state. <...> The calculated optimized geometric parameters (bond lengths and bond angles), vibrational frequencies and NMR chemical shifts for the minimum energy conformers were seen to be in a good agreement with the corresponding experimental data. <...> All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. <...> These studies have showed that low energy conformations appear corresponding to the orientation of the acetoxy group with respect to the rest of the molecule. <...> They have calculated five low lying conformations by molecular mechanics computing. <...> Theoretical study of acetylcholine bromide has denoted that the experimental gauche-gauche conformation corresponds only to a local energy minimum about 2 kcalŒmol–1 above the global one associated with a different gauche-gauche conformation [ 12 ]. Karakaya M., Ucun F., 2013 . 258 – 268 -. 2013. . 54, 2 259 As seen from the above discussion the ground state conformation of acetylcholine is labile and influenced by its environment. <...> In this study we wish to report the vibrational and NMR analysis of acetylcholine halides to obtain the minimum energy conformations in the ground state by means of density functional theory (B3LYP) method. <...> COMPUTATIONAL DETAILS The optimized structure parameters and vibrational frequencies for acetylcholine halides (AChF, AChCl and AChBr) were calculated by density functional theory (B3LYP) method at 6-311G(d) basis set level. <...> The calculated vibration frequencies were scaled with a scale factor of 0.9614 [ 15 ] and clarified by means of the potential energy distribution (PED) analysis and assignments of all the fundamental vibrational modes using VEDA 4 program [ 16 ]. <...> In Table 2 are given the electronic energies, relative energies and mean vibrational deviations. <...> The relative energy values and calculated vibrational deviations in the table are respect to the lowest energy conformer I. As seen the mean vibrational deviation increases while the relative energy in Fig. 1. <...> Therefore, we state that the more different the molecular structures of two conformers is <...>

• Похожие документы из РУАЭСТ
• |
• Похожие документы из Руконт