Syntheses, Structural Characterization of Two Novel Zigzag Cu(II)/Co(II)‐Based Coordination Polymers as Multifunctional Agents for Biosensing, Catecholase, and Cytotoxic Activity

In this work, two novel zigzag one‐dimensional Co(II) and Cu(II) coordination polymers (CPs) ( CP1 and CP2 ) derived from 2,5–dihydroxyterephthalic acid and 2,2′–bipyridine (2,2′–bipy) ligands were synthesized and characterized by UV–vis, FTIR, EPR, sc–XRD, and analytical methods. Single crystal X‐ray investigations of CP1 and CP2 revealed a monoclinic crystal system with an I2/a and P2 1 /m space group, and the refinement parameters were calculated as a = 7.3729(10) Å, b = 23.754(4) Å, c = 13.682(3) Å ( CP1 ) and a = 7.2349(3) Å, b = 14.0835(4) Å, c = 11.3166(3) Å ( CP2 ). The DFT investigations were employed to examine the electronic and structural properties of CP1 and CP2 , and the results revealed that HOMO electron density was restricted around the central metal ions, whereas LUMO electron density was diffused throughout the polymeric structures and was predominantly localized on 2,2′–bipy ligand. Additionally, the Hirshfeld surface (HS) analysis was carried out to study the various intra‐/intermolecular interactions that stabilize the crystal structure, and our results showed that CP1 and CP2 were majorly stabilized by H–H (55.5% and 43.8%) interactions. The chemotherapeutic efficacy of CP1 and CP2 were explored by studying the in vitro DNA binding interactions utilizing multispectroscopic techniques including UV–visible, fluorescence, circular dichroism, and cyclic voltammetry. The binding strength ( K b ) of CP1 and CP2 with DNA was calculated to be 6.1 (±0.17) × 10 4 and 8.77 (±0.43) × 10 4 M −1 , respectively. The synthesized CPs were also evaluated for their biosensing activity, and the finding revealed that CP1 showed selective sensing for levofloxacin (LVF), whereas CP2 proved to be an efficient sensor for chloramphenicol (CLAM), LVF, and nitrofurantoin (NFT). We have further evaluated the catechol oxidase activity of CP1 , and the activity of CP2 was assessed by using 3,5–DTBC as a potential substrate. The V max values were calculated to be 5.23 × 10 −5 and 6.67 × 10 −5 Ms −1 for CP1 and CP2 , respectively. The chemotherapeutic potential of CP1 and CP2 was ascertained by carrying out in vitro cytotoxicity against neuroblastoma (SH–SY5Y) cell line employing cisplatin as a reference, and the results displayed better anticancer activity of CP2 , which was reflected from their IC 50 values.