Enhanced Photostability of a Ruthenium(II) Polypyridyl Complex under Highly Oxidizing Aqueous Conditions by Its Partial Inclusion into a Cyclodextrin.

Abstract

The complex [Ru(bpy)2 L](2+) , where bpy=2,2'-bipyridine, L=4-(phenylethynyl)-2,2'-bipyridine, was prepared in its racemic and resolved forms (Δ and Λ). The phenylethynyl unit on the bipyridine for the complex acts as a binding site for α-cyclodextrin in water (1:1 complex, K=3390 L mol(-1) ) or β-cyclodextrin (2:1 complex, K1 =887 L mol(-1) , K2 =8070 L mol(-1) ). The presence of the cyclodextrin provides partial protection to the complex under light-activated water oxidation conditions.