Density Functional Theory Study on Conformers of Benzoylcholine Chloride

Abstract

The optimized molecular structures and vibrational frequencies and also gauge including atomic orbital (GIAO)1H and13C NMR shift values of benzoylcholine chloride [(2-benzoyloxyethyl) trimethyl ammonium chloride] have been calculated using density functional theory (B3LYP) method with 6-31++G(d) basis set. The comparison of the experimental and calculated infrared (IR), Raman, and nuclear magnetic resonance (NMR) spectra has indicated that the experimental spectra are formed from the superposition of the spectra of two lowest energy conformers of the compound. So, it was concluded that the compound simultaneously exists in two optimized conformers in the ground state. Also the natural bond orbital (NBO) analysis has supported the simultaneous exiting of two conformers in the ground state. The calculated optimized geometric parameters (bond lengths and bond angles) and vibrational frequencies for both the lowest energy conformers were seen to be in a well agreement with the corresponding experimental data.

Effects of neutral and charged substituents on the infrared carbonyl stretching frequencies in phenyl and alkyl benzoates in DMSO

“…A good correlation of the ν CO values with the σ°constants for para-substituted phenyl benzoates, once more, shows the absence of the through resonance between the electron-donating substituents and the carbonyl group and that in phenyl esters, the carbonyl group was found to be nearly perpendicular to the aroxy plane. [10,62,78,79] The substituent constants, σ°X ± , for charged substituents estimated with Eqn 7 using the corresponding carbonyl stretching frequencies, ν CO , in DMSO (Table 1) and the value of ρ m,p from [41] . b Ref [42] .…”