Excited state properties of a metallofulvene: Photochemical release of a carbene from RuII(phenylindenylidene)(PCy3)2Cl2 induced by MLCT excitation

The metallofulvene or carbene complex RuII(PI)(PCy3)2Cl2 with PI = 3-phenylindenylidene and Cy = cyclohexyl shows a long-wavelength absorption at λmax = 490 nm which is attributed to a RuII → π∗ carbene MLCT transition. MLCT excitation leads to a reversible release of the carbene ligand which can be intercepted by oxygen. The oxygen adduct (or O-oxide) undergoes a fragmentation which yields CO2 and anthracene.