Title: DFT investigation of the electronic structure of amphetamines: effect of substituent on O and N chemical shielding and electric field gradient tensors

Authors: Zahra Fallah Ebrahimi; David J.D. Wilson

Addresses: Department of Chemical Engineering, École Polytechnique de Montréal, Montréal, QC, Canada ' Department of Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Victoria, Australia

Abstract: To understand the relationship between the electronic structure of amphetamines and their biological activity, a computational investigation was carried out to characterise the 17O and 14N, electric field gradient (EFG) tensors and nuclear quadrupole coupling constants (NQCC) as well as 17O, 15N, 13C and 1H chemical shielding tensors of amphetamines. Calculation were performed with the B3LYP and PW91P86 density functional theory (DFT) methods with the 6-311++G(d,p) basis set. The anisotropic (Δσ) and isotropic (σiso) shielding are in good agreement with the available experimental data. The results indicate that the EFG and σ at oxygen are insensitive to substitution at the N and C10 positions in amphetamines. In contrast, the nitrogen EFG and σ are quite sensitive towards substituent changes. Furthermore, it was found that EFG tensors are more sensitive than σ tensor to the electron density distribution in amphetamines. Biological activities of amphetamines were found to depend upon the electron density distribution in the region of N atoms.

Keywords: electric field gradient; EFG tensors; NMR; NQR; amphetamines; ecstasy; density functional theory; DFT; chemical shielding tensors; computational chemistry; electronic structure; biological activity; nuclear quadrupole coupling constants; NQCC; oxygen; nitrogen.

DOI: 10.1504/IJCBDD.2015.073669

International Journal of Computational Biology and Drug Design, 2015 Vol.8 No.4, pp.311 - 325

Received: 02 Nov 2014
Accepted: 22 Apr 2015

Published online: 15 Dec 2015 *

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