Synthesis, structure, terahertz spectroscopy and luminescent properties of copper(I) complexes with mercaptan ligands and triphenylphosphine

•Seven new complexes were synthesized and characterized.•Complexes 1–5 represent first examples of HMNBT and HAMTD with copper(I) halides.•The complexes 1, 5, 6 and 7 exhibit interesting fluorescence in the solid state.•THz-TDS of starting materials and complexes were investigated.•Our results show several factors can affect the THz spectra of the complexes.

The reactions of copper(I) halides with triphenylphosphine (PPh3) and mercaptan ligand [2-mercapto-6-nitrobenzothiazole (HMNBT), 2-amino-5-mercapto-1,3,4-thiadiazole (HAMTD) and 2-mercapto-5-methyl-benzimidazole (MMBD)] yielded seven complexes, [CuCl(HMNBT)(PPh3)2] (1), [CuX(HMNBT)(PPh3)]2 (X = Cl, Br) (2–3), [Cu(MNBT)(HMNBT)(PPh3)2] (4), [CuBr(HAMTD)(PPh3)2]·CH3OH (5) and [CuX(MMBD)(PPh3)2]·2CH3OH (X = Br, I) (6–7). These complexes were characterized by elemental analysis, X-ray diffraction, 1H NMR and 31P NMR spectroscopy. In these complexes the mercaptan ligands act as monodentate or bridged ligand with S as the coordination atom. In complexes 1 and 4, hydrogen bonds CH⋯X and weak interactions CH⋯π lead to the formation of chains and 2D network respectively, while complexes 2 and 3 are dinuclear. In 5–7, intramolecular hydrogen bonds link the [CuX(thione)(PPh3)2] molecules and the solvated methanol molecules into centrosymmetric dimers. Complexes 1–5 represent first copper(I) halide complexes of HMNBT and HAMTD. The complexes 1, 5, 6 and 7 exhibit interesting fluorescence in the solid state at room temperature and their terahertz (THz) time-domain spectroscopy was also studied.