XRD/HSA, noncovalent interactions and influence of solvent polarity on spectral properties of dithiocarbazate schiff base and its cis-Cu(II) complex: Experimental and theoretical studies

Abstract

A N,S-bidentate ligand (LH) was synthesized via the condensation of S-benzyldithiocarbazate with acetophenone. The produced Schiff base ligand was reacted with a copper(II) salt to yield a neutral cis-Cu(II) complex. The influence of solvent polarity on spectral properties were demonstrated for the new complex in different organic solvents. The global reactivity parameters were estimated by means of energy values of the frontier molecular orbitals. Both the desired LH and its complex have been characterized by XRD-crystal analysis. In solid state the LH exists in a thione tautomeric form, while the deprotonated form of is chelated to the Cu(II) center through neutral nitrogen of azomethine and ionic sulfur of thiol, giving rise to tetrahedrally distorted square planar geometry around the metal center, in which the two ligands coordinated in cis-configuration. The noncovalent interactions were evaluated via Hirshfeld surface analysis (HSA), reflecting the presence of four position of short contacts for both the free ligand and its complex. Moreover, the formation of hydrogen bonds of the types NH⸱⸱⸱S=C and CH⸱⸱⸱S=C were observed in the ligand structure, while H⸱⸱⸱Caromatic interactions were perceived in both structures of the ligand and complex, approved by the XRD-packing results.