Synthesis, characterization, and computational study of copper bipyridine complex [Cu (C₁₈H₂₄N₂) (NO₃)₂] to explore...

In the present study, copper (II) complex of 4, 4'-di-tert-butyl-2,2'-bipyridine [Cu (C₁₈H₂₄N₂) (NO₃)₂], 1 is investigated through its synthesis and characterization using elemental analysis technique, infra-red spectroscopy, and single-crystal analysis. The compound 1 crystallizes in orthorhombic space group P2₁2₁2₁. The copper atom in the mononuclear complex is hexa coordinated through two nitrogen and four oxygen atoms from bipyridine ligand and nitrate ligands. The thermal analysis depicts the stability of the entitled compound up to 170 °C, and the decomposition takes place in different steps between 170 and 1000 °C. Furthermore, quantum chemical techniques are used to study optoelectronic, nonlinear optical, and therapeutic bioactivity. The values of isotropic and anisotropic linear polarizabilities of compound 1 are calculated as 41.65 × 10^-24 and 23.02 × 10^-24 esu, respectively. Likewise, the static hyperpolarizability is calculated as 47.92 × 10^-36 esu using M06 functional compared with para-nitroaniline (p-NA) and found several times larger than p-NA. Furthermore, the antiviral potential of compound 1 is studied using molecular docking technique where intermolecular interactions are checked between the entitled compound and two crucial proteins of SARS-CoV-2 (COVID-19). Our investigation indicated that compound 1 interacts more vigorously to spike protein than main protease (M^Pro) due to its better binding energy of -9.60 kcal/mol compared with -9.10 kcal/mol of M^Pro. Our current study anticipated that the above-entitled coordination complexes could be potential candidates for optoelectronic properties and their biological activity.