Syntheses, structure, DNA docking and antimicrobial studies of copper(II) complexes with diethylenetriamine and N-bidentate ligands

[Display omitted] •Heteroleptic copper(II) complexes with diethylenetriamine and bidentate ligands were synthesized.•All complexes were characterized by spectroscopic techniques and SXRD.•Docking studies of these complexes showed strong binding affinity towards DNA.•All complexes exhibited good antibacterial activity. A series of mononuclear heteroleptic copper(II) complexes with diethylenetriamine (DETA) and bidentate N-donor ligands, [Cu(DETA)(5,6-DMPhen)](ClO4)21, [Cu(DETA)(4,7-DMPhen)](ClO4)2, 2, [Cu(DETA)(3,4,7,8-TMPhen)](BPh4)2, 3, [Cu(DETA)(8-AQ)](ClO4)2, 4, [Cu(DETA)(2-AMP)](ClO4)2, 5, [Cu(DETA)(2-AEP)](ClO4)2, 6, [Cu(DETA)(1,2-DACH)](ClO4)2, 7 and [Cu(DETA)(1,3-DAP)](ClO4)2, 8, with biologically relevant N-donor ligands 5,6-dimethyl-1,10-phenanthroline (5,6-DMPhen), 4,7-dimethyl-1,10-phenanthroline (4,7-DMPhen), 3,4,7,8-tetramethyl-1,10-phenanthroline (3,4,7,8-TMPhen), 8-aminoquinoline (8-AQ), 2-aminomethylpyridine (2-AMP), 2-aminoethylpyridine (2-AEP), 1,2-diaminocyclohexane (1,2-DACH) and 1,3-diaminopropane (DAP) respectively. All the complexes (1–8) were structurally determined by a single-crystal X-ray diffraction technique and characterized by CHN, UV–Vis, FT-IR, and ESI-MS. X-ray analysis revealed that the geometry around the copper center in all complexes (1–8) is distorted trigonal bipyramidal. All complexes strongly bind with ct-DNA via groove/electrostatic interactions. Their binding with DNA was supported by UV–Vis and CD spectral studies. Docking studies revealed that copper(II) complexes containing aromatic N-donor ligands (5,6-DMPhen, 4,7-DMPhen, 3,4,7,8-TMPhen & 8-AQ) have a stronger binding affinity than complexes with aliphatic N-donor ligands (2-AMP, 2-AEP, 1,2-DACH & DAP) towards DNA. All complexes exhibited good antibacterial activity against American standard ATCC Escherichia coli (ATCC 25922) and clinically isolated Escherichia coli (E1) bacterial strains.