title: 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⋯N hydrogen bonding in the conformational properties of thiadiazol-pyrrolidin-2-ol bearing species.
abstract: 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 21.9kJ/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⋯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.
authors.affiliation: CEQUINOR (UNLP, CONICET-CCT La Plata), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Bv. 120 e/60 y 64 N° 1465, C.C. 962, 1900 La Plata, Buenos Aires, Argentina.
authors.forename: Sergio L
authors.initials: SL
authors.lastname: Laurella
authors.affiliation: CEQUINOR (UNLP, CONICET-CCT La Plata), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Bv. 120 e/60 y 64 N° 1465, C.C. 962, 1900 La Plata, Buenos Aires, Argentina. Electronic address: erben@quimica.unlp.edu.ar.
authors.forename: Mauricio F
authors.initials: MF
authors.lastname: Erben
mesh_terms: D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D017550:Spectroscopy, Fourier Transform Infrared; D014732:Vibration
keywords: Conformation; Heterocyclic compounds; Hydrogen bond; NBO; Pyrrolidine; Thiadiazole