Hybrid inorganic-organic complexes: Synthesis, spectroscopic characterization, single crystal X-ray structure determination and antimicrobial activities of three copper(II)-diethylenetriamine-p-nitrobenzoate complexes

Three new hybrid inorganic-organic complexes: [Cu(dien)(pnb)2]·H2O, 1; [Cu(dien)2](pnb)2, 2; and [Cu(dien)(pnb)(H2O)](pnb)(Hpnb), 3 (where pnb = p-nitrobenzoate, dien = diethylenetriamine, tridenate N-donor ligand), have been synthesized at room temperature and characterized by spectroscopic (FT-IR, UV–Vis, EPR) methods. The structures of all newly synthesized complexes 1–3 have been unambiguously established by single crystal X-ray structure determination. All the complexes 1–3 showed variation in the coordination environment around copper(II) metal center obtained under slightly different reaction conditions by using same reactants but different synthetic routes at room temperature. Crystal lattices of coordination complexes 1–3 are stabilized by various non-covalent interactions such as N-H…O, C-H…O, O-H…O etc. All the three copper(II) complexes 1–3 show significant antimicrobial activity against gram positive bacteria.