Structures and luminescence properties of two copper(I) halide complexes featuring 2-(2-benzimidazolyl)-6-methylpyridine

Two new copper(I) halide complexes bearing 2-(2-benzimidazolyl)-6-methylpyridine (Hbmp) and PPh3 ligands, Cu(Hbmp)(PPh3)X (X = Br (1); I (2)), have been synthesized and characterized. Single-crystal X-ray structure analysis reveals that the halide ligand has a significant impact on the CuNpyridyl bond lengths. Complexes 1 and 2 show the solid-state emissions at ambient temperature, varying with the halide bound to the {Cu(Hbmp)(PPh3)} motif, which are perhaps best attributed to the metal-to-ligand charge-transfer (Cu(I) → Hbmp) transition mixed with some ligand-to-ligand charge-transfer (X and PPh3 → Hbmp) character.