title: Possibility of the existence of donor-acceptor interactions in bis(azole)amines: an electronic structure analysis.
abstract: Donor-stabilized divalent N(I) systems have recently gained attention in the field of organic chemistry. Existence of low-valent nitrogen(I) species with moderate nucleophilicities in several pharmacophoric functionalities is prompting extensive exploration in this field. Quantum chemical analysis on the imidazole, oxazole, and thiazole derivatives of thiazole-2-amine indicated that these species preferably exist in the iminic state. Electronic structure analysis of these systems suggested the existence of hidden divalent N(I) character in a neutral state (L → N-R) and the explicit divalent N(I) character (L → N ← L)(+) in the protonated state. The strength of L → N interaction in these systems was analyzed, and the variations in the nucleophilicity trend at the coordinating nitrogen center were rationalized by estimating the electronic (TEP (Tolman electronic parameter) and MESP minimum (V(min))) as well as steric parameters (r-repulsiveness and ΔH elimination of CO group, in L → Ni(CO)3) of the coordinating ligands L. The importance of energetically preferred ionic and tautomeric representations of thiazol-2-amine derivatives in iminic and aminic forms was also demonstrated by carrying out comparative docking analysis with the enzyme lymphocyte-specific kinase (Lck).
authors.affiliation: Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER) , Sector 67, S. A. S. Nagar, Punjab 160 062, India.
authors.forename: Sonam
authors.initials: S
authors.lastname: Bhatia
authors.forename: Prasad V
authors.initials: PV
authors.lastname: Bharatam
mesh_terms: D000588:Amines / Q000737:chemistry*; D001393:Azoles / Q000737:chemistry*; D003198:Computer Simulation; D004583:Electrons; D007093:Imidazoles / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry*; D013844:Thiazoles / Q000737:chemistry*
chemical_list: D000588:Amines; D001393:Azoles; D007093:Imidazoles; D008024:Ligands; D013844:Thiazoles; C029899:imidazole; D009584:Nitrogen