Synthesis and luminescence of cuprous bromide compound of 2-(2-benzimidazolyl)-6-methylpyridine

Copper (I) complexes have been widely investigated for their favorable photophysical properties and excellent potential applications. A mononuclear copper(I) bromide compound Cu(Hbmp)(PPh₃)Br (1) (where Hbmp denotes 2-(2-benzimidazolyl)-6-methylpyridine) was synthesized by treating cuprous bromide in dichloromethane with triphenylphosphine and Hbmp used as a bidentate chelating ligand. Both the crystal structure and the solidstate emission of complex 1 were studied. The research revealed that the copper atom of complex 1 is four - coordinate locating in a distorted tetrahedral configuration formed by one bromine atom, one phosphorus atom, and two nitrogen atoms. These adjacent Cu(Hbmp)(PPh₃)Br molecules orderly stack and array one another via weak in termolecular π-π interactions between the Hbmp ligands and assemble into an one-dimensional chain arrangement. Complex 1 displays a strong solid-state photo-phosphorescence at ambient temperature, which is ascribed to the metal -to -lig and charge transfer (MLCT) transition mixed with some halide -to -ligand charge transfer (XLCT) character.