A Sublimable Dinuclear Cuprous Complex Showing Selective Luminescence Vapochromism in the Crystalline State

A new sublimable dicopper(I) complex bearing 1,2-bis-(diphenylphosphino)ethane and 5-trifluoromethyl-3-(2'- pyridyl)pyrazolate ligands has been designed and synthesized, and its crystalline solvated and nonsolvated compounds have also been obtained and investigated. It is shown that only the crystalline solvated compound exhibits reversible and selective luminescence vapochromism, arising from its unique pyridyl/CH2Cl2/pyridyl organic sandwich-like stacking arrangement revealed by X-ray crystallography, as supported by time dependent density functional theory calculations. Additionally, the neutral Cu(I) complex has excellent thermal stability and sublimability, good solid-state luminescence properties, and TADF character, and it is suggested to be a good emitter for vapor-deposited organic light-emitting diodes.