Theoretical investigation on molecular structure of a new mononuclear copper(II) thiocyanato complex with tridentate Schiff base ligand

Abstract

An asymmetrical Schiff base ligand, 4-bromo-2-(2-pyridylmethyliminomethyl)phenol (HL), and its copper(II) complex, [Cu(L)SCN] (1), have been synthesized. Complex 1 is experimentally characterized by elemental analysis, FT-IR and UV–vis spectroscopic techniques, and cyclic voltammetry. The structure of the complex has been established by single-crystal X-ray diffraction studies, which reveal a square planar geometry of the central copper(II) ion in 1. The neighboring molecules of the complex connect each other by π–π stacking interactions with centroid-to-centroid ring distance 3.653 Å. The ligand can display two possible tautomeric forms; therefore, 1 can have an alternate molecular structure. DFT calculations have been employed to investigate the structure and relative stabilities of the suggested tautomeric forms of the ligand and its corresponding copper(II) complex.

Keywords:

• Schiff base
• copper(II) complex
• crystal structure
• tautomer stability
• DFT calculations

Acknowledgement

S. Thakurta gratefully acknowledges Jadavpur University, Kolkata, India for supporting this study. A. Frontera thanks the MINECO of SPAIN (project CTQ2014-57393-C2-1-P, FEDER funds) for funding and the CTI (UIB) for free allocation of computer time.