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

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 pseudo‐tetrahedral geometries. All the complexes in powder at 293 K display bright phosphorescence with the highest photoluminescent 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. [ABSTRACT FROM AUTHOR]