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, [Cd-4(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 greater than or equal to 5 x 10(9) 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 nu(Cd-S), however, the electron donor is more appropriately characterized as an individual sulfur atom, rather than a delocalized assembly.