Synthesis, spectroscopic characterization and quantum chemical computational studies on 4-(3-methyl-3-phenylcyclobutyl)-2-(2-undecylidenehydrazinyl)thiazole

The Schiff base compound, 4-(3-methyl-3-phenylcyclobutyl)-2-(2-undecylidenehydrazinyl)thiazole, (C25H37N3S), was synthesized and characterized combining several experimental techniques (X-ray, 1H NMR and 13C NMR) and theoretical methods. The compound crystallizes in the monoclinic space group P 21/c with a = 16.2306 (6) Å, b = 6.728 (2) Å, c = 26.1834 (10) Å, β = 120.687 (3), and Z = 4. The initial molecular geometry (X-ray coordinates) was optimized using Hartree–Fock (HF) and Density Functional Theory (DFT/B3LYP) method with the 6-31+G(d, p) basis set in ground state. From the optimized geometry of the molecule, geometric parameters, vibrational frequencies, gauge-independent atomic orbital (GIAO) 1H and 13C NMR chemical shift values of the title compound have been calculated theoretically and compared with the experimental data. Data from theoretical calculations show excellent consistency with experimental results. Besides, molecular electrostatic potential (MEP) distribution, frontier molecular orbitals (FMOs) and non-linear optical (NLO) properties of the title molecule were investigated by theoretical calculations.