Ni(II) complex containing a thiosemicarbazone ligand: Synthesis, spectroscopy, single-crystal X-ray crystallographic and conductivity studies

In this study, 4-(diphenylamino)benzaldehyde-4-(2-fluorophenyl)thiosemicarbazone (LH) ligand was synthesized from the reaction of 4-diphenylaminobenzaldehyde and 2-fluorophenyl thiosemicarbazide. The NiL2 complex containing LH ligand were synthesized and characterized using elemental analysis, infrared spectroscopy, magnetic susceptibility, molar conductivity and UV-Vis spectroscopy. X-ray structure was determined for both the LH ligand and the NiL2 complex. LH ligand was also characterised via H-1 NMR and C-13 NMR spectroscopy. FTIR data determined the coordination mode of the ligand with Ni(II) metal ion. The FTIR spectra shows that the LH ligand behave as mononegative bidentate through azomethine (N=C) and (C-S) groups with Ni(II) metal ion. The electronic spectra and magnetic measurements agreed well with a square planar geometry for NiL2 complex with the value of 0.00 B.M. Further confirmation of NiL2 complex was determined through single X-ray Crystallography which indicated a distorted square planar geometry which the angles deviated from 90 degrees with a maximum value of 7 degrees. In addition, the structure of LH ligand presented a thione form and the molecule has crystallized in triclinic crystal system with P-(1) over bar space group. Conductivity studies of polymer electrolyte (PE) films composed of carboxymethyl cellulose (CMC) polymer, propylene carbonate as a plasticizer and LH/NiL2 compound as a dopant were prepared by a solution casting technique. The conductivity of the prepared PE films was studied using Electrochemical Impedance Spectroscopy (EIS). The conductivity was observed for LH ligand and NiL2 complex at 3.73 x 10(-9) S cm(-1) and 9.81 x 10(-9) Scm(-1), respectively. (C) 2020 Elsevier B.V. All rights reserved.