New copper(II) ternary complexes formulated as [Cu(N‐N)BIG]ClO4, where BIG is deprotonated 2‐((1H‐benzimidazol‐2‐yl)methylamino)acetic acid and N‐N represents 2,2′‐bipyridine (1) or 4,4′‐dimethyl‐2,2′‐bipyridine (2) or 5,5′‐dimethyl‐2,2′‐bipyridine (3) or 1,10‐phenanthroline (4) or 4,5‐diazafluoren‐9‐one (5) or dipyridylamine (6), were synthesized and characterized using analytical and spectral methods. Complex 1 was characterized using single‐crystal X‐ray diffraction analysis and found to be monomeric in nature with distorted square pyramidal geometry. The binding interactions of 1–6 with calf thymus DNA were studied using UV–visible absorption and emission spectroscopy and viscosity measurements. The DNA cleavage ability of 1–6 with pUC19 DNA shows that the complexes can cleave DNA without any external agents. The ligand and complexes were investigated for their in vitro antibacterial activity against Bacillus subtilis and Staphylococcus aureus. The complexes showed enhanced antibacterial activities compared to the free ligand. Molecular docking studies of complexes 1–6 were made using Genetic Optimization of Ligand Docking (GOLD) software. The study indicated that LEU23, ASP25, ILE84, ASN144 and ARG87 of COX‐2 were important for strong hydrogen bonding interaction with the complexes. Among the complexes, 2 showed the best docking result with COX‐2. Cytotoxicity assay was performed using MTT reagent against human cervical cancer cells, human breast cancer cells and human lung cancer cells. The complexes were found to show moderate anticancer activity.

A novel water-soluble carboxylate-bridged copper(II) coordination polymer, Cu-BIG was formed by the reaction of Cu(ClO 4) 2 • 6H 2 O and tridentate benzimidazole-glycine conjugate ligand, 2-((1H-benzimidazol-2-yl)methylamino) acetic acid, BIGH and its structure has been determined by IR, UV, powder XRD, VSM, CV, TGA, DTA, EPR and single crystal X-ray diffraction. Crystallographic studies indicate it to be a coordination polymer with Pī Space group. The asymmetric unit of complex contains two Cu(II) ions with elongated square pyramid geometry. The axial positions of the Cu(II) atoms are occupied by the carbonyl oxygen of the carboxylate group with the bond distances Cu(1)-O(5) axial , 2.28 Å, and Cu(2)-O(2) axial , 2.26 Å. The two Cu(II) are connected through the carboxylic group present in BIGH, which provides electron mobilisation in the molecule and hence results in the soft ferromagnetic polymer. An in vitro antibacterial activity study of BIGH and Cu-BIG showed moderate activity against Bacillus subtilis. The DNA binding studies showed the interaction of Cu-BIG with CT-DNA.

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