Experimental and Theoretical Investigation of the Molecular and Electronic Structure of 5-(4-Aminophenyl)-4-(3-Methyl-3-Phenylcyclobutyl)thiazol-2-Amine

Abstract

The title molecule, 5-(4-aminophenyl)-4-(3-methyl-3-phenylcyclobutyl) thiazol-2-amine (C<inf>20</inf>H<inf>21</inf>N<inf>3</inf>S), was prepared and characterized by 1H-NMR, 13C-NMR, IR and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2<inf>1</inf>/c with a = 9.4350(5) Å, b = 11.2796(6) Å, c = 18.4170(8) Å and β = 113.378(3)°. In addition to the molecular geometry from X-ray experiment, the molecular geometry, vibrational frequencies, gauge including atomic orbital (GIAO) 1H- and 13C-NMR chemical shift values and atomic charges distribution of the title compound in the ground state have been calculated using the Hartree - Fock (HF) and density functional method (DFT) (B3LYP) with 6-31G(d) basis set. To determine conformational flexibility, molecular energy profile of the title compound was obtained by semi-empirical (AM1) calculations with respect to two selected degrees of torsional freedom, which were varied from -180° to +180° in steps of 10°. Besides, frontier molecular orbitals (FMO) analysis was performed by the B3LYP/6-31G(d) method. © Springer-Verlag 2009.