Photochemical molecular devices incorporating reactive metals as supramolecular solar H2 photocatalysts

PETR 28

David F. Zigler, dfzigler@vt.edu, Shamindri M. Arachchige, arachsm@vt.edu, Jared Brown, jrbmbm3@vt.edu, Krishnan Rangan, and Eric Chang. Department of Chemistry, Virginia Tech, Blacksburg, VA 24061-0212
The design of complicated supramolecular complexes that couple Ru(II) and Os(II) polyazine complexes to reactive metal centers provides access to light activated molecular devices that can be applied in a wide array of forums. The supramolecular complexes described are complicated assemblies composed of multiple subunits. Each subunit provides a function that, when combined into the supramolecule, allows for complex functioning of the assemblies. The application of supramolecular complexes to solar energy conversion will be described. (Elvington, M.C.; Brown, J.; Arachchige, S.; Brewer K. J. J. Am. Chem. Soc. 2007, 129, 10644). Ru(II) and Os(II) polyazine complexes are charge transfer light absorbers in which excited state properties can be modulated by ligand selection. The incorporation of bridging ligands allows for the construction of supramolecular assemblies. Reactive Rh(III) metal centers provide for utilization of the energy harvested by the LA units through reaction with substrates. The modulation of properties of the supramolecular assemblies by component modification will be described. The application of these supramolecular complexes to visible light induced production of H2 from water and the factors impacting functioning will be explored. Acknowledgement is made to the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U. S. Department of Energy for their generous support of this research. The authors wish to acknowledge the financial collaboration of Phoenix Canada Oil Company which holds long term license rights to commercialize the Rh based H2 technology.