Synthesis, characterization, and DFT calculations of a copper(II) complex with lamivudine

Abstract

Lamivudine (C8H11N3O3S, Lami), also known as 3TC, is a pharmaceutical compound renowned for its inhibitory effects on the reverse transcriptase enzyme found in retroviruses such as HIV (human immunodeficiency virus) and HBV (hepatitis B virus). A coordination complex between Lami ligand and the Cu(II) ion, described by the chemical formula Cu(Lami)₄(ClO₄)₂·3H₂O (for short, CuLami), underwent thorough examination and the molecular structure of the Cu(Lami)₄+2 complex was determined by single-crystal X-ray diffraction techniques. The compound crystallizes in the orthorhombic space group P212121. Copper(II) ion is coordinated by four Lami molecules, acting as bidentate ligands, strongly through their pyridinic N-atoms at the 3-position in a square environment and weakly through their carbonyl O-atoms. This results in the metal laying on the 4-fold inversion axis of an approximate S4 site symmetry. EPR spectrum corroborated the above CuN₄O4 core. Furthermore, the complex underwent comprehensive characterization via elemental and thermogravimetric analyses, atomic absorption spectroscopy, FTIR, Raman, NMR, UV–vis, and fluorescence spectroscopies. Additionally, assignments for observed bands in FTIR and UV–vis were validated through DFT calculations. Solubility tests favored acetonitrile (ACN) for solution assays due to its matching absorption spectrum with the solid and stability times of up to two hours. Finally, the cytotoxicity of the complexes was screened against the tumoral A549 cell line.