Synthesis and Reactivity of 1,2-Bis(chlorodimethylgermyl)carborane and 1,2-Bis(bromodimethylstannyl)carborane

The 1,2-bis(chlorogermyl)- (1) and 1,2-bis(bromostannyl)carborane (2) have been prepared by the reaction of dilithio-o-carborane with Me2GeCl2 and Me2SnBr2, respectively. Compounds 1 and 2 are found to be good precursors for the synthesis of a variety of cyclization compounds. The Wurtz-type coupling reaction of 1 and 2 using sodium metal afforded the four-membered digerma compound 3 and five-membered tristanna compound 4, respectively. The salt elimination reactions of 1 and 2 using Li2NtBu and Li2PC6H5 afforded the cyclic products (5, M = Ge, E = NtBu; 6, M = Sn, E = NtBu; 7, M = Ge, E = PC6H5; 8, M = Sn, E = PC6H5). The 1,2-bis(dimethylgermyl)carborane 9 and 1,2-bis(dimethylstannyl)carborane 10 were prepared by the reaction of 1 and 2 with sodium cyanoborohydride. The reactions of 9 and 10 with Pd(PPh3)4 afforded the bis(germyl)palladium 12 and bis(stannyl)palladium 13 complexes, respectively

Synthesis and Reactivity of 1,2-Bis(chlorodimethylgermyl)carborane and 1,2-Bis(bromodimethylstannyl)carborane

The 1,2-bis(chlorogermyl)- (1) and 1,2-bis(bromostannyl)carborane (2) have been prepared by the reaction of dilithio-o-carborane with Me2GeCl2 and Me2SnBr2, respectively. Compounds 1 and 2 are found to be good precursors for the synthesis of a variety of cyclization compounds. The Wurtz-type coupling reaction of 1 and 2 using sodium metal afforded the four-membered digerma compound 3 and five-membered tristanna compound 4, respectively. The salt elimination reactions of 1 and 2 using Li2NtBu and Li2PC6H5 afforded the cyclic products (5, M = Ge, E = NtBu; 6, M = Sn, E = NtBu; 7, M = Ge, E = PC6H5; 8, M = Sn, E = PC6H5). The 1,2-bis(dimethylgermyl)carborane 9 and 1,2-bis(dimethylstannyl)carborane 10 were prepared by the reaction of 1 and 2 with sodium cyanoborohydride. The reactions of 9 and 10 with Pd(PPh3)4 afforded the bis(germyl)palladium 12 and bis(stannyl)palladium 13 complexes, respectively

Oligophenylenevinylene-Functionalized Ru(II)-bipyridine Sensitizers for Efficient Dye-Sensitized Nanocrystalline TiO₂ Solar Cells

New 4- and 4,4‘-oligophenylenevinylene-functionalized Ru(II)-bipyridine sensitizers were synthesized and used in dye-sensitized TiO2 solar cells (DSSCs) to study their sensitizing properties relative to those of the usual N3 dye. Among those studied, two sensitizers, denoted as D5 and D6, have rendered considerably higher photocurrents and efficiencies for their cells, compared to those of a cell using the conventional N3 dye. The short-circuit photocurrent densities for N3, D5, and D6 are 9.8, 10.8, and 11.7 mA/cm2, and the efficiencies are 4.1, 4.6, and 4.8%, respectively. The enhanced photocurrents are correlated with the increased molar absorption coefficients of the D5 and D6 dyes over the entire visible spectra region, relative to those of the N3 dye. Corresponding enhancements in IPCE values are attributed to the oligophenylenevinylene groups of D5 and D6 that consist of conjugated double bonds. Analysis of the absorption spectra of the sensitizer-coated TiO2 films and the desorbed dyes in an aqueous KOH solution indicates that D5 and D6 adhere more strongly to TiO2 particles than the N3 dye, which is beneficial from the viewpoint of the long-term stability of the DSSCs