High-Energy Metal to Ligand Charge-Transfer States in Ruthenium-Diimine Complexes

Article abstract of DOI:10.1021/j100357a018

Earlier emission and absorption contours for the ²⁺ complex were anormalous.In addition, the photoselection spectra (emission and excitation) differ from that found previously for (dpy)2 complexes.Speculation was that these differences result from the high-energy metal to ligand charge-transfer (MLCT) state in this complex.Consquently, a number of bis Ru(II) chelate complexes with varying energy MLCT states were examined to rationalize these experimental results.The result with use of perturbation theory demonstrate an interaction between the singlet MLCT states and ?-?^* states for these materials.The correlations of the emission Stokes shift and the zero-order energy of the singlet MLCT state indicate that singlet absorption and triplet emission derive from states of different orbital configuration.Predictions of the symmetry of the absorbing singlet and emitting triplet from a simple model are consistent with the results obtained earlier from the interchromophoric coupling model.