Experimental and theoretical investigation of the molecular and electronic structure of 5-(4-aminophenyl)-4-(3-methyl-3-phenylcyclobutyl)thiazol-2-amine

The title molecule, 5-(4-aminophenyl)-4-(3-methyl-3-phenylcyclobutyl)thiazol-2-amine (C₂₀H₂₁N₃S), was prepared and characterized by ¹H-NMR, ¹³C-NMR, IR and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/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.