Syntheses, crystal structures and Hirshfeld surface analyses of bis(2-mercaptobenzimidazole)bromo- and iodocopper(I) complexes

The title complexes, bromidobis(2,3-dihydro-1H-1,3-benzodiazole-2-thione)copper(I), [CuBr(C7H6N2S)(2)] (1), and bis(2,3-dihydro-1H-1,3-benzodiazole-2-thione)iodidocopper(I) acetone monosolvate, [CuI(C7H6N2S)(2)]center dot CH3-COCH3 (2), were prepared by the reaction of copper(I) bromide/iodide with 2-mercaptobenzimidazole. Both complexes have mononuclear structures with the copper atom coordinated by two 2-mercaptobenzimidazole molecules via their S atoms and one halide atom in an approximate trigonal-planar arrangement. In their extended structures, N-H center dot center dot center dot S hydrogen bonds and pi-pi contacts are found in both complexes; as a result of the acetone solvent molecule in (2), N-H center dot center dot center dot O contacts are also observed. Hirshfeld surface analyses were carried out to aid in the visualization of these interactions, which showed that H center dot center dot center dot H contacts contribute 34.6% for (1) and 34.1% for (2) to the overall surface, followed by contributions from H center dot center dot center dot S/S center dot center dot center dot H, H center dot center dot center dot C/C center dot center dot center dot H and C center dot center dot center dot C contacts, respectively. As expected, H center dot center dot center dot O/O center dot center dot center dot H contacts are observed only in (2). The IR and H-1 and C-13 NMR spectra of (1) and (2) are described.