A Structurally Diverse RuII,PtII Tetrametallic Motif for Photoinitiated Electron Collection and Photocatalytic Hydrogen Production

Authors

  • Jessica D. Knoll,

    1. Department of Chemistry, Virginia Polytechnic Institute and State University, 107 Davidson Hall, Blacksburg, VA 24061-0212, Fax: (+1) 540 231 3255
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  • Dr. Shamindri M. Arachchige,

    1. Department of Chemistry, Virginia Polytechnic Institute and State University, 107 Davidson Hall, Blacksburg, VA 24061-0212, Fax: (+1) 540 231 3255
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  • Dr. Karen J. Brewer

    Corresponding author
    1. Department of Chemistry, Virginia Polytechnic Institute and State University, 107 Davidson Hall, Blacksburg, VA 24061-0212, Fax: (+1) 540 231 3255
    • Department of Chemistry, Virginia Polytechnic Institute and State University, 107 Davidson Hall, Blacksburg, VA 24061-0212, Fax: (+1) 540 231 3255
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Abstract

Coupling a reactive metal to light absorbers affords molecular devices for photoinitiated electron collection and photocatalytic conversion of substrates to fuels. A new RuII,PtII tetrametallic supramolecule, [{(phen)2Ru(dpp)}2Ru(dpq)PtCl2](PF6)6, and the trimetallic precursors, [{(phen)2Ru(dpp)}2RuCl2](PF6)4 and [{(phen)2Ru(dpp)}2Ru(dpq)](PF6)6, have been synthesized, and their redox, spectroscopic, spectroelectrochemical, photophysical and photocatalytic properties studied. They efficiently absorb UV and visible light. The electrochemistry of [{(phen)2Ru(dpp)}2Ru(dpq)PtCl2](PF6)6 suggests a lowest-lying terminal Ru→dpq charge-separated state that quenches the emission of the parent complex with non-unity population of the emissive 3MLCT excited state. Photolysis of [{(phen)2Ru(dpp)}2Ru(dpq)PtCl2]6+ at 470 nm with DMA gives multielectron reduction, storing electrons in a new manner on the central (dpp)2RuII(dpq) moiety. Addition of H2O to the photolysis system produces 21 μmol of H2 in 5 h, with 115 turnovers of the tetrametallic photocatalyst.

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