The electronic absorption spectrum and structure of the emitting state of the tris(2,2′-bipyridyl)ruthenium( II ) complex ion

The directly determined absorption spectrum (250–650 nm) of the optically excited species *[Ru(bipy)3]2+(bipy = 2,2′-bipyridyl) is presented and assigned. The promoted (metal to ligand charge transfer) electron is localised on one of the three bipy ligands, as in the formulation [RuIII(bipy)2(bipy–)]2+, while the known emission photoselection data imply that the promoted electron resides on the same ligand throughout.