X-ray structures, spectroscopic, antimicrobial activity, ESP/HSA and TD/DFT calculations of Bi(III) complex containing imidazole ring

A novel complex [Bi(L)(2)(NO3)(3)] ( L = 2-(4-imidazolyl)-4-methyl-1,2-dihydroquinazoline-N3-oxide) was synthesized via complexation of the quinazoline ligand L with Bi(III) nitrate pentahydrate in methanol and ethyl acetate. The structure of complex was determined by elemental analysis, FT-IR, UV-vis and fluorescence spectroscopy, as well as characterized by X-ray crystallography. Crystallographic analysis divulged that the central atom Bi(III) was coordinated with eight atoms and the ratio of ligand-to-metal was 2:1. Specially, it fostered into an infinite 1-D chain, 2-D layered and ladder-like 3-D supramolecular skeleton through different intermolecular interactions. In addition, the fluorescence behaviors of Bi(III) complex in six solvents of diverse polarities were quite different. The DFT/B3LYP theoretical level has been successfully applied to calculate the optimized geometry, electronic distribution of HOMO-LUMO and the electrostatic potential diagram of Bi(III) complex. Meanwhile, the electronic transitions recorded by TD/DFT calculation theoretically rationalized the UV-vis spectrum data. The antibacterial activity of Bi(III) complex against Escherichia coli and Staphylococcus aureus were further studied. Plausible non covalent interactions were quantified using Hirshfeld surfaces and 2D fingerprint plots. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

A novel complex was synthesized and characterized in this study. It exhibited diverse supramolecular structures and fluorescence behaviors, and showed antibacterial activity against Escherichia coli and Staphylococcus aureus.