title: Divalent N(I) character in 2-(thiazol-2-yl)guanidine: an electronic structure analysis.
abstract: Several medicinally important compounds carry a 2-(thiazol-2-yl)guanidine unit. These species are generally (erroneously) represented as 1-(thiazol-2-yl)guanidine species. Quantum chemical studies were performed to identify the appropriate tautomeric state of this class of compounds. B3LYP/6-31+G(d) calculations indicate the preferred tautomeric state of these species is associated with the 2-(thiazol-2-yl)guanidine structure rather than the 1-(thiazol-2-yl)guanidine structure. G2MP2 calculations on the model system were carried out to study the electronic structure, electron delocalization, and protonation energy; MESP, ELF, HOMA, AIM, and NBO analyses were also carried out. The results indicate that this class of compounds may be treated as species with hidden ::N(←L)R character. Upon protonation of the thiazole ring nitrogen, these systems show the electronic structure as in ::N(←L)2(⊕) systems with divalent N(I) oxidation state.
authors.affiliation: Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER) , Sector 67, S. A. S. Nagar, Punjab 160062, India.
authors.forename: Sonam
authors.initials: S
authors.lastname: Bhatia
authors.forename: Chandrakant
authors.initials: C
authors.lastname: Bagul
authors.forename: Yoganjaneyulu
authors.initials: Y
authors.lastname: Kasetti
authors.forename: Dhilon S
authors.initials: DS
authors.lastname: Patel
authors.forename: Prasad V
authors.initials: PV
authors.lastname: Bharatam
mesh_terms: D003198:Computer Simulation; D004583:Electrons; D006146:Guanidines / Q000737:chemistry*; D008958:Models, Molecular; D009584:Nitrogen / Q000737:chemistry*; D013844:Thiazoles / Q000737:chemistry*
chemical_list: C000591938:2-(thiazol-2-yl)guanidine; D006146:Guanidines; D013844:Thiazoles; D009584:Nitrogen