Comment on 'Structural and vibrational studies on 1-(5-Methyl- [1,3,4] thiadiazol-2-yl)-pyrolidin-2-ol' [Spectrochimica Acta Part A, 152 (2016) 252-261]. The importance of intramolecular OH center dot center dot center dot N hydrogen bonding in the conformational properties of thiadiazol-pyrrolidin-2-ol bearing species

摘要

The title paper [1] reports a study on the spectroscopic and physicochemical properties of 1-(5-methyl[1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol (MTPN) based on experimental and theoretical data. The latter ones are based on the computed molecular structure for a rather unusual conformer. Here, after a careful analysis of the conformational space of MTPN, the most stable conformation was determined for the molecule isolated in a vacuum, which results to be 21.9 kJ/mol more stable than the conformer reported previously. Our study also includes the closely related species 1-(5-trifluoromethyl-[1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol (FMTPN). An intramolecular OH center dot center dot center dot N hydrogen bond determines the conformational behavior of the [1,3,4]thiadiazol-2-yl)-pyrrolidin-2-ol group as demonstrated by Natural Bond Orbital population analysis. (C) 2016 Elsevier B.V. All rights reserved.