A Redox Asymmetric, Cyclometalated Ruthenium Dimer: Toward Upconversion Dyes in Dye-Sensitized TiO2 Solar Cells

作者：Wadman Sipke H; van Leeuwen Y M; Havenith Remco W A; van Klink Gerard P M; van Koten Gerard^*

来源：Organometallics, 2010, 29(21): 5635-5645.

DOI：10.1021/om100865k

We have prepared the dinuclear ruthenium complexes [(R-3-tpy)Ru((NCN)-C-boolean AND-N-boolean AND-tpy)Ru(tpy)](3+) (R = H ([5a](3+)), CO2Me ([6a](3+)), (NC)-C-boolean AND(H)N-boolean AND-tpy = 4'(3,5-dipyridylphenyl)-2,2':6',2 ''-terpyridine, tpy = 2,2':6',2 ''-terpyridine) and [(R-3-tpy)Ru((NCN)-C-boolean AND-N-boolean AND'-tpy)Ru(tpy)](3+) (R = H ([5b](3+)), CO2Me ([6b](3+)), N'C-boolean AND(H)N-boolean AND'-tpy = 4'(3.5-di(4-tert-butylpyridyl)phenyl)-2,2':6',2 ''-terpyridine) in a stepwise manner. The directional nature of the bridging ligand, which is potentially cyclometalating on one side, induces large redox asymmetry in the resulting dinuclear complexes. One-electron oxidation gives rise to a strong metal-to-metal charge transfer transition from the [Ru(tpy(2))](2+) moiety to the cycloruthenated group, centered at 1034 nm for [6b](4+). The localized nature of the oxidation processes, the shape of the NIR band, and TD-DFT calculations allow assignment of these systems to localized Robin-Day class II. Exclusive substitution of the terminal tpy ligand on the cyclometalated ruthenium with acid moieties allows selective attachment of the dye to a semiconductor surface, whereby a possible two-step upconversion path is created in dye-sensitized solar cells for the utilization of low-energy photons.

• 出版日期2010-11-8