Light Induced Cluster-to-Organic-Acceptor Charge Transfer in a Molecular CadmiumSulfide Assembly

摘要

The molecular cluster, (Cd4(S-C6H4NO2)10).N(CH3)42, exhibits an intense near-UVabsorption that is absent in the corresponding benzenethiolate cluster. Resonance Raman and electronic Stark effect studies show that the absorption feature originates from a pair of closely spaced cluster-to-nitrobenzene charge-transfer transitions. The lower lying charge-transfer excited state is weakly luminescent. Time resolved luminescence measurements yield a nonradiative decay or back electron transfer rate (nitrobenzene to cluster) of 330,000,000/s. Further analysis of resonance Raman scattering reveals that at least 7 vibrational modes are coupled, in a Franck-Condon sense, to the electron transfer process. In terms of absolute normal coordinate displacement, the two most important modes are Cd-S and N-O stretches. jg.