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An experimental and theoretical study of the preferred hydrogen bonding site of methyl isothiocyanate
Author(s) -
Illien Bertrand,
Evain Karine,
Berthelot Michel,
Laurence Christian
Publication year - 2003
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.652
Subject(s) - chemistry , hydrogen bond , bond dissociation energy , dissociation (chemistry) , enthalpy , gibbs free energy , sulfur , hydrogen , computational chemistry , potential energy surface , crystallography , molecule , organic chemistry , thermodynamics , physics
The hydrogen‐bond acceptor properties of MeNCS were investigated in vacuo with theoretical (MP2 and DFT) calculations, in CCl 4 and (CF 3 ) 2 CHOH solutions by Fourier transform infrared spectrometry and in the solid state through the Cambridge Structural Database. These methods show that MeNCS is a sulfur base in hydrogen bonding. The electrostatic potential at the molecular surface is more negative by 36 kJ mol −1 around S than around N. The hydrogen bonding of HF is more favorable to sulfur than to nitrogen by ca 5, 4 and 7 kJ mol −1 , respectively, on the dissociation energy, enthalpy and Gibbs energy scales (B3LYP calculations). The selectivity of hydrogen bonding sites appears to be governed by a push–pull mechanism (electrons going from N to S) rather than by hardness. Towards a phenol, the order of sulfur basicity is . Copyright © 2003 John Wiley & Sons, Ltd.