Luminescence studies of dinuclear platinum(II) alkynyl complexes and their mixed-metal platinum(II)-copper(I) and -silver(I) complexes

Abstract

Two series of dinuclear platinum(II) alkynyl complexes, [Pt2(μ-dppm)2(μ-C≡CR) (C≡CR)2]+ (in A-frame structure) and [Pt2(μ-dppm)2(C≡CR)4] (in face-to-face structure), were synthesized and characterized. All of them exhibit rich photoluminescence in degassed solutions and in the solid-state. Their emissions were assigned as derived from states of triplet metal-metal bond-to-ligand charge transfer (3MMLCT) origin. The effects of the variation of alkynyl substituents and Pt⋯Pt bond distances on their photophysical behaviours have been studied. Resonance Raman (RR) spectroscopic experiments supported the spectral assignments and variable-temperature NMR studies showed the fluxional properties of the A-frame complexes. Encapsulation of copper(I) or silver(I) ion in between the two alkynyl groups in one of the face-to-face complexes [Pt2(μ-dppm)2(C≡CPh)4], via π-coordination was found to vary its luminescence properties. © 2002 Elsevier Science B.V. All rights reserved.