Luminescent thione/phosphane mixed-ligand copper(I) complexes: The effect of thione on structural properties

Reactions of [CuX(PPh3)]4 (X=Br, Cl) with five-membered ring, N-heterocyclic thiones results in the synthesis of photoluminescent thione/phosphane copper(I) complexes, either binuclear S-thione-bridged or mononuclear with terminal thione. [Display omitted] •Synthesis and X-ray structures of copper(I) complexes with a mixed set of halide, PPh3 and heterocyclic thione ligands.•Two distinct types of structural motifs: binuclear centrosymmetric thione-bridged or mononuclear complexes.•All complexes are photoluminescent in the solid state with emission maxima in the 400–490nm range. The reactions of tetrameric clusters [CuX(PPh3)]4 (X=Br or Cl) with a series of small size, five-member ring N-heterocyclic thiones, 5-methyl-1,3,4-thiadiazole-2-thione (mtdztH), 5-amino-1,3,4-thiadiazole-3-thione (atdztH) and 4,5-diphenyl-imidazole-2-thione (dpimdztH), in 1:4molar ratio, in acetonitrile/methanol mixtures, resulted in the isolation of symmetrical, mixed-ligand phosphane/thione-S-bridged dicopper species of the general type [CuX(PPh3)(μ-S-thione)]2, with the copper centers being in distorted tetrahedral coordination environments consisting of a PS2X donor set. In contrast, analogous reactions with the less basic and more sterically demanding 1-phenyl-tetrazole-5-thione (dpimdztH) afforded mononuclear mixed-ligand complexes with the general formula [CuX(PPh3)2(thione)], in which the thione acts in a terminal bonding mode. All copper(I) complexes are found to be photoluminescent in the solid state at ambient temperature, with their emission maxima influenced by the type of heterocyclic thione, as well as (to a smaller extent) the halide present in each case.