ELECTRON-TRANSFER IN PHENOTHIAZINE RU(BPY)3(2+) DONOR-CHROMOPHORE COMPLEXES/

Time-resolved emission studies have been performed on a series of cova lently linked Ru(bipyridine)(3)-phenothiazine complexes. The emissive Ru(bipyridine)(3) metal-to-ligand charge-transfer (MLCT) excited state is quenched by electron donation from a phenothiazine (PTZ) donor. Th e rates of electron transfer (ET) to the MLCT states from the PTZ dono r have been analyzed in terms of Marcus theory, in which each phenothi azine acts independently of other phenothiazines in the complex. React ion energetics were determined from electrochemical data for Ru(2+/1+) and PTZ(1+/0) reduction potentials and MLCT state energies. Quantitat ive agreement was found between the model's predictions and measured E T times. The results are compared to those obtained for the analogous electron transfer leading to charge separated state formation in a rel ated donor-chromophore-acceptor system.