Spectroscopic and photophysical studies of apparent cluster-to-organic-acceptor charge transfer in a molecular cadmium sulfide assembly

A nitrobenzene (NB) decorated cadmium sulfide cluster, [Cd4(SNB)10][N(CH3)4]2, has been prepared and examined spectroscopically. The assembly exhibits an intense cluster-to-attached-acceptor charge-transfer band at 376 nm. Observation of back electron transfer (nitrobenzene to cluster) via time resolved luminescence yields a rate constant of ≥ 5 × 109 s−1. Raman studies show that seven vibrational modes are coupled to the electron transfer reaction and that those exhibiting the greatest initial-state/final-state displacements are the CdS and NO stretches. Despite the activity of νCd-S, however, the electron donor is more appropriately characterized as an individual sulfur atom, rather than a delocalized assembly.