Synthesis, structure, photophysics, time-resolved emission spectroscopy and electrochemistry of luminescent copper(I) acetylide complexes

Abstract

A series of soluble trinuclear copper(I) complexes containing mono- and bi-capped μ 3-η 1-acetylides [Cu 3(dppm) 3(μ 3-η 1-C≡CR)] 2+ and [Cu 3(dppm) 3(μ 3-η 1-C≡CR) 2] + (dppm = Ph 2PCH 2PPh 2, R = Ph or Bu t) have been synthesized and shown to exhibit long-lived dual luminescent behaviour. Their photophysics and electrochemistry and those of a mixed halide-acetylide capped trinuclear copper(I) complex [Cu 3(dppm) 3(μ 3-η 1-C≡CBu t)(μ 3-Cl)] + have been investigated. The origin of the low-energy emission (λ em 525-700 nm) is ascribed to states of ds/l.m.c.t. admixture with large l.m.c.t. (ligand to metal charge transfer) character. The crystal structure of [Cu 3(dppm) 3(μ 3-η 1-C≡CBu t)][PF 6] 2 has been determined. The complex consists of an isosceles triangular array of copper atoms with Cu-Cu distances of 2.910(1), 2.941(2) and 3.175(1) Å.