Synthesis, crystal structure, characterization and antimicrobial activities of ternary chiral mononuclear Schiff base copper(II) complexes

Abstract

[CuL^1–4(tmen)] is a sequence of four ternary mononuclear Schiff base copper(II) complexes that are derived from L-valine, suitable 5′-substituted-2′-hydroxyacetophenones (where the substituents are -Cl for L¹, -Me for L², -OMe for L³, and -H for L⁴), and tmen (where tmen-N,N,N′,N′ tetramethyl ethylenediamine). Without isolating the Schiff base ligand or producing any other intermediate products, all of the complexes were synthesised. These compounds were identified using elemental analysis, molar conductance, UV-Vis, FTIR, EPR, VSM-RT, and CD spectra. Single crystal XRD was used to characterise the structure of Complex 1. The crystalline structure exhibits a distorted square pyramidal shape wherein the Schiff base forms an axial bond with the Cu(II) ion through the ONO-donor, while the chelating ligand tmen exhibits both an equatorial and an axial mode of binding through the NN-donor atoms. Hydrogen bonding and non-covalent CH(methyl)π(phenyl) interaction are two intriguing aspects of compound 1's packing diagram. By calculating the minimum inhibitory concentration (MIC) against harmful bacteria, the synthesised complexes' antimicrobial activity was assessed. According to the bioactivity experiments, the microorganisms employed in this investigation were susceptible to the antibacterial and antifungal properties of copper(II) complexes 1–4. According to the bioactivity experiments, the microorganisms employed in this investigation were susceptible to the antibacterial and antifungal properties of copper(II) complexes 1–4.