(1-Methyl-2-(thiophen-2-yl)-1H-benzo[d]imidazole) and its three copper complexes: Synthesis, characterization and fluorescence properties

(1-Methyl-2-(thiophen-2-yl)-1H-benzo[d]imidazole) (C12H10N2S) (L) ligand and its three copper complexes [(Cu2(L)2I2] (1), [(Cu(L)2X2] (X = Cl− (2), and NO3− (3)) were synthesized and characterized by elemental analysis and IR measurements. The structures of the complexes 1–3 were determined by single crystal X-ray diffraction. The complex molecules interact with each other’s via weak CH⋯X hydrogen bonds (X = I for the complex 1, X = Cl for the complex 2 and X = O for the complex 3). Upon excitation with a wavelength of 350 nm at room temperature, free L and complex 1 emit fluorescence at 420 and 560 nm, respectively.