This project is in the general field of analytical and surface chemistry and in the subfields of photochemistry and electrochemistry. Chemical synthetic methods will be employed to prepare a wide variety of linked intramolecular electron transfer systems that have unique properties absent in non-linked systems. The complexes are based on trisbipyridine (II) as a light-harvesting photocenter. This photocenter is covalently linked via flexible linkages to N,N'-diquaternary- 2,2'-bipyridinium as an electron acceptor and/or N-alkyl phenothiazine as an electron donor. In other series, triply bridged heterodinuclear ruthenium/rhodium complexes with relatively rigid linkages will be studied. Ground state properties will be characterized by electrochemical, spectroelectrochemical and spectroscopic methods. Electron transfer rates will be determined by time-resolved emission and absorption spectroscopy. Combined electrochemical, photochemical and photophysical studies of linked donor/acceptor photosensitizer systems will lead to a better understanding on the molecular level of light-induced electron transfer systems. The results will aid in the design of more efficient molecular systems for converting light emergy into useful chemical energy.
