Solution Behavior and Optical Properties of Platinum Complexes Featuring “Pt(pq)(C≡CtBu)” Units Connected by N-donor Ligands

The synthesis, spectroscopic (including X-ray for 2a and 4a) and optical properties of a series of
binuclear complexes [{Pt(pq)(C≡CtBu)}2{μ-(N-N)}] (1a–5a), having ditopic dinitrogen linker ligands
(N-N) and of a trinuclear [{Pt(pq)(C≡CtBu)}3(μ-L)] (6a) featuring a 1,3,5-tris(pyridine-4-
ylethynyl)benzene as a central core are presented. In this chapter particular attention is devoted to the
unusual behavior of the binuclear complexes illustrated with complex [{Pt(pq)(C≡CtBu)}2{μ-4,4’-bpy)}]
(2a). Thus, upon solution, complexes 1a-5a establish a fast dynamic equilibrium with the alkynyl
bridging starting material [Pt(pq)(μ-C≡CtBu)]2 (Pt-1), the corresponding mononuclear complex with a
terminal N-donor ligand [Pt(pq)(C≡CtBu)(N-N)] (1b-5b) and the free ligand (N-N). Additionally, the
effects of concentration, temperature and solvent properties on the equilibrium, and their optical
properties (absorption and emission), supported also by theoretical calculations on 2a, are
commented.