Molecular vibrational investigation [FT-IR, FT-Raman, UV–Visible and NMR] on Bis(thiourea) Nickel chloride using HF and DFT calculations

•Bis(thiourea) Nickel chloride was investigated by IR, Raman and NMR tool.•The chemical shift of the compounds is favor for its change of chemical property.•The kubo gap related confirms the charge transformation between base and ligand.•Owing to the large hyperpolarizability, the compound has optical activity.

In the present research work, the FT-IR, FT-Raman spectra of the Bis(thiourea) Nickel chloride (BTNC) were recorded and analyzed. The observed fundamental frequencies in finger print and functional group regions were assigned according to their uniqueness region. The computational calculations were carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The present organo-metallic compound was made up of covalent and coordination covalent bonds. The modified vibrational pattern of the complex molecule associated with ligand group was analyzed. Furthermore, the 13C NMR and 1H NMR spectral data were calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP/6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts linked to TMS were compared. A investigation on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies were carried out. The kubo gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The NLO properties related to Polarizability and hyperpolarizability based on the finite-field approach were also discussed.

Graphical abstractThe present compound Bis(thiourea) Nickel chloride is very important for the fabrication of NLO crystals. The main cause of the NLO activity of the molecule is hydrogen bond and the creation of coordinate covalent bond. The virtual conjugation of nickel atom with organic molecule is also main background of the inducement of the NLO property of the compound. The kubo gap of the present compound is calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand. The NLO properties related to Polarizability and hyperpolarizability based on the finite-field approach are also discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide