Luminescent mono‐and dinuclear copper(I) complexes based on bulky bisphosphino‐substituted benzimidazole derivatives

Abstract

Four mono-and two dinuclear Cu(I) complexes were synthesized based on novel 4-diphenylphosphino-benzimidazole (P^N) derivatives, and their structures as well as photophysical properties were systematically investigated. X-ray crystallographic analysis reveals that the Cu(I) centers adopt pseudotetrahedral geometries. All the complexes in powder at 293 K display bright phosphorescence with the highest photolumines-cent quantum yield of 37.6 %. The emission maxima could be finely tuned from 514 to 592 nm by the methoxy substituent on the N^P ligands. The combined experimental results at different temperature (293 K and 77 K) and theoretical studies suggest that the nature of the emissive states can be mainly assigned as a dominant charge-transfer character involving major components of 3 (M + X) LCT transitions.