Synthesis, characterization, and computational study of three-coordinate SNS-copper(I) complexes based on bis-thione precursors

A series of tridentate pincer ligands, each possessing two sulfur and one nitrogen donor (SNS), based on bis-imidazolyl or bis-triazolyl salts were metallated with CuCl2 to give new tridentate SNS pincer copper(I) complexes [(SNS)Cu]+. These orange complexes exhibit a three-coordinate pseudo-trigonal-planar geometry in copper. During the formation of these copper(I) complexes, disproportionation is observed as the copper(II) salt precursor is converted into the Cu(I) [(SNS)Cu]+ cation and the [CuCl4]2– counteranion. The [(SNS)Cu]+ complexes were characterized with single crystal X-ray diffraction, electrospray mass spectrometry, EPR spectroscopy, attenuated total reflectance infrared spectroscopy, UV–Vis spectroscopy, cyclic voltammetry, and elemental analysis. The EPR spectra are consistent with anisotropic Cu(II) signals with four hyperfine splittings in the lower-field region (g||) and g values consistent with the presence of the tetrachlorocuprate. Various electronic transitions are apparent in the UV...