Highly Emissive Hexanuclear Rhenium(III) Clusters Containing the Cubic Cores [Re6S8]2+and [Re6Se8]2+

Clusters based on the cubic, hexanuclear rhenium(III) core [Re6(μ3-Q)8]2+ (Q = S, Se) emit red phosphorescence with microsecond-scale lifetimes. Emission quantum yields of 16 clusters range from 1% to 23%; those having O-bound terminal ligands feature the highest yields and the longest liftimes. Certain clusters are photolabile, with medium-sensitive emissive properties. When photodecomplexation is suppressed, all clusters herein obey the energy gap law, indicating excitation confined to the [Re6Q8]2+ core.