A Simple Example of the Fluxional Behaviour of Ruthenium-CoordinatedC2-Symmetric Monodentate Ligands − Synthesis,1H NMR Spectroscopic Study, and Crystal Structure ofcis-[Ru(bpy)2(4Pic)2](PF6)2

Abstract

In complexes of the type cis-[Ru(bpy)2(L)2](PF6)2 the fluxional behaviour (dynamics of rotation) of the monodentate heterocyclic ligands (L) in solution can be well investigated with 1H NMR spectroscopy. As both the cis-[Ru(bpy)2] moiety and the coordinated 4-picoline have a C2 symmetry, no atropisomers of cis-[Ru(bpy)2(4Pic)2](PF6)2 are possible, and as a result a relatively easily understandable 1H NMR spectrum is observed. The fast and slow rotation of the 4-picoline ligands have been monitored using variable-temperature 1D and 2D 1H NMR spectroscopy. In addition the room temperature, solid state, X-ray structure is presented.