Chelate Formation around a Hexarhenium Cluster Core by the Diphosphane Ligand Ph2P(CH2)6PPh2

Substitution of the iodide ions in the octahedral hexarhenium cluster [Re6Se8I6]3− by the diphosphane Ph2P(CH2)nPPh2 generates “bridge–chelate” complexes when n=6 (dpph) with general formula [Re6Se8I6−2m(μ-dpph)m]2m−4 (m=1–3; the picture shows the trans isomer for m=2), whereas for n=5 only a monodentate binding mode of the diphosphane is found. Stepwise substitution by dpph strongly affects the redox processes, while the photophysical properties associated with the [Re6Se8]2+ core change only moderately.