Emission tuning in dinuclear gold complexes with diphosphanes containing alkyne and/or oligophenylene spacers

Abstract

Reaction of the diphosphanes P∼P [PPh₂(C₆H₄)_nPPh₂ (n = 1–5) and PPh₂CC(C₆H₄)CCPPh₂] with [AuX(tht)] (X = Cl, C₆F₅) in a 1 : 2 molar ratio affords dinuclear luminescent complexes of formula [(AuX)₂(P∼P)]. The photoemissive properties of these complexes are mainly controlled by the presence of the diphosphane ligand, specifically by the phenylene spacers of the diphosphanes. At room temperature fluorescent (IL) processes dominate the emissions, both in solution and in the solid state. Frozen solutions or solids at 77 K display dual emissions or only one emission attributed to ligand to ligand charge transfer (LL′CT) transitions from the auxiliary ligand (L) to phenylene spacers of the diphosphane (L′).