Two Cu(I) complexes based on semicarbazone ligand: synthesis, crystal structure, Hirshfeld surface and anticancer activity evaluation against human cell lines

Abstract

Two novel Cu(I) complexes with the 2-acetylpyridine-N(4)-phenyl semicarbazone (HL) ligand, [CuCl (HL)(PPh3)]∙CH3CN (1) and [CuBr (HL)(PPh3)] (2), were investigated by single-crystal X-ray analysis, Hirshfeld surface, and physicochemical and spectroscopic methods. In both cases, the Schiff base was coordinated by the bidentate ligand via the pyridine nitrogen and the iminic nitrogen atoms. A molecule of triphenylphosphine and a halide ion (Cl− or Br−) completed the coordination sphere of the metal centers. The geometry around the copper atoms was distorted tetrahedral geometry. The secondary coordination sphere of Cu(I) is pentacoordinated and has weak interactions Cu···O of 2.906(1) A and 2.783(1) A. The 3D Hirshfeld surface and the 2D fingerprint plots of the complexes were analyzed quantitatively to verify the presence of intermolecular interactions. By their crystal structure of (2), it is possible to observe π···π stacking interactions between the pyridyl and phenyl rings from HL and also between phenyl rings and the triphenylphosphine ligands forming a 1D network. The biological activity of the Cu(I) salts, the free semicarbazone, and its Cu(I) complexes was evaluated against human cancer cell lines MCF-7 and nontumor cell lines PBMC.