Syntheses, characterization, single crystal X-ray structures and antimicrobial activities of four Cu(II) 3-halobenzoate complexes; Cu(3-chloro/bromobenzoate)2 in the presence of heterocyclic N-donor ligands β/γ-picolines

Abstract

The reaction of hydrated copper(II) 3-chloro/bromobenzoates with β/γ-picoline in a methanol:water mixture (4:1 v/v) yielded four monomeric complexes, [Cu(3-chlorobenzoate)2(β-picoline)2] (1), [Cu(3-chlorobenzoate)2(γ-picoline)2(H2O)] (2), [Cu(3-bromobenzoate)2(β-picoline)2(H2O)] (3) and [Cu(3-bromobenzoate)2(γ-picoline)2)] (4). The newly synthesized complexes have been characterized by elemental analyses, spectroscopic methods (FT-IR, UV–Vis), TGA and single crystal X-ray structure determination. Crystallographic investigations revealed that all the copper(II) 3-halobenzoates complexes with β-/γ-picoline ligands are monomeric in nature, in contrast to polymeric copper(II) 2-halobenzoate complexes in the presence of similar N-donor ligands. Various non-covalent interactions, like O–H⋯O, C–H⋯O, C–H⋯π and anion ⋯π, have been observed to play a decisive role in the stabilization of the crystal lattices in all the complexes. All the newly synthesized copper(II) complexes show significant antibacterial activity against gram negative and gram positive bacteria.