Synthesis, structures and photophysical properties of copper(I) 2-(2-benzimidazolyl)-6-methylpyridine complexes with different diphosphine ligands

Abstract

A series of new Cu(I) 2-(2-benzimidazolyl)-6-methylpyridine (Hbmp) complexes containing five different diphosphine auxiliary ligands have been synthesized and well characterized. It is revealed that all Cu(I) atoms display distorted N2P2 tetrahedral geometries with distinct P–Cu–P bond angles regulated by diverse diphosphine ancillary ligands, in which Hbmp serves as a charge-neutral chelating ligand without the deprotonation of the benzimidazolyl-NH while the diphosphine ligand adopts a bridging or chelating coordination mode. It is demonstrated that all these Cu(I) complexes show a relatively weak low-energy absorption in solution and exhibit good luminescence properties in solution and solid states at room temperature, which are more markedly influenced by the P–Cu–P bond angle.