Photoswitchable trinuclear transition-metal complexes. Intramolecular triplet–triplet energy transfer from fac-(diimine)ReI(CO)3 chromophores to a stilbene-like bridging ligand

A series of novel trinuclear metal complexes containing fac-(diimine)ReI(CO)3 chromophores and a stilbene-like bridging ligand have been synthesized and in CH3CN exhibit photoswitchable luminescence arising from photoinduced intramolecular energy transfer from the fac-(diimine)- Re(CO)3 chromophores to the bridging ligand.