Mixed-ligand copper(I) halide complexes bearing 4,5-bis(diphenylphosphano)-9,9-dimethyl-xanthene and N-methylbenzothiazole-2-thione: Synthesis, structures, luminescence and antibacterial activity mediated by DNA and membrane damage

Abstract

The 1:1M-ratio reaction between copper(I) bromide or iodide and 4,5-bis(diphenylphosphano)-9,9-dimethyl-xanthene (xantphos) in acetonitrile results in the formation of [CuX(xantphos)] (X=Br, I), which further reacts with N-methylbenzothiazole-2-thione (mbtt) to afford the mononuclear mixed-ligand complexes [CuX(xantphos)(mbtt)]. The molecular structures of the complexes, established by single-crystal X-ray diffraction, feature a distorted tetrahedral geometry around the metal center, with the diphosphane acting as a chelate. The new compounds are strongly emissive in the solid state at room temperature. The complexes were also screened for antibacterial activity and their ability to interact with CT-DNA in vitro and to produce reactive oxygen species (ROS).