Crystal structure of a copper complex containing the 4-bromo-2-{[(2-hy-droxy-eth-yl)imino]-meth-yl}phenol base Schiff ligand.

Abstract

The coordination co-crystal (4-bromo-2-{[(2-hy-droxy-eth-yl)imino]-meth-yl}pheno-lolato-κ³ O,N,O')(thio-cyanato-κN)copper(II)-5-bromo-2-hy-droxy-benz-alde-hyde-water (2/1/1), [Cu(C₉H₉BrNO₂)(NCS)]·0.5C₇H₅BrO₂·0.5H₂O or [Cu(HL)(SCN)]₂·C₇H₅BrO₂·H₂O, crystallizes in the monoclinic space group P2₁/c. The asymmetric unit contains two mononuclear units of the complex, each consisting of one deprotonated ligand, one thio-cyanate anion (SCN^-) coordinated through its nitro-gen atom, one free water mol-ecule, and one free 5-bromo-salicyl-aldehyde mol-ecule, forming a co-crystal. The copper atom is four-coordinate, adopting a slightly distorted square-planar geometry defined by the tridentate ligand and the nitro-gen atom of the thio-cyanate anion. Bond length values show that the thio-cyanate ion has a linear S-C≡N arrangement, typical of a terminal, N-bound iso-thio-cyanate group. The water mol-ecule plays a key role in linking the two complex units through O-H⋯O hydrogen bonds. In the crystal, C-H⋯O and C-H⋯Br hydrogen bonds allow the free 5-bromo-salicyl-aldehyde mol-ecule to form a bridge between two adjacent layers. Additional O-H⋯O, C-H⋯S, O-H⋯S, and C-H⋯N inter-actions further consolidate the overall structure.