Anion-cation charge-transfer properties and spectral studies of [M(phen)_3][Cd_4(SPh)_(10)] (M = Ru, Fe, and Ni)

摘要

Three anion-cation compounds 1-3 with formula [M(phen)_3][Cd _4(SPh)_(10)]·Sol (M = Ru~(2+), Fe ~(2+), and Ni~(2+), Sol = MeCN and H_2O) have been synthesized and characterized by single-crystal analysis. Both the cations and anion are well-known ions, but the properties of the co-assembled compounds are interesting. Molecular structures and charge-transfer between the cations and anions in crystal and even in solution are discussed. These compounds are isomorphous and short inter-ion interactions are found in these crystals, such as π?π stacking and C-H?π contacts. Both spectroscopic and theoretical calculated results indicate that there is anion-cation charge-transfer (ACCT) between the Ru-phen complex dye and the Cd-SPh cluster, which plays an important role in their photophysical properties. The intensity of the fluorescent emission of the [Ru(phen)_3]~(2+) is enhanced when the cation interacts with the [Cd_4(SPh)_(10)]~(2-) anion. The mechanism for the enhancement of photoluminescence has been proposed.