Unprecedented luminescence behavior of coinage metal π-diborene complexes

A number of unprecedented photophysical phenomena are observed in the study of luminescent π-diborene complexes of Cu and Ag, including unusually high fluorescence quantum yields in solution for complexes of these metals (up to unity). This indicates that very little or no intersystem crossing between S1 and Tn occurs in the complexes, despite the strong spin-orbit coupling of the metal atoms. The substitution of carbon for boron thus yields luminescent isolobal analogues of otherwise non-emissive olefin complexes of Cu and Ag