Regioselective iron-catalyzed cross-dehydrogenative coupling (CDC) of two aromatic compounds using tert-BuOOH as oxidant under mild conditions has been reported. The direct oxidative coupling reaction is selective toward creation of a carbon-carbon bond at the position ortho to the functional groups of the substrates, completely preventing the homocoupled products. The C-C bond-forming reaction makes the method versatile, leading to functionalized 2,2' -disubstituted biaryls.

A combination of a meso substituted zinc-porphyrin with two pyridyl groups and two benzoate groups at cis positions to each other (POR) with a mononuclear ruthenium(II) complex containing a 2,6bis(1-methylbenzimidazol-2-yl)pyridine ligand and a carboxylic acid functionalized terpyridine ligand (SPS-G3) has been used as co-sensitizing system for the fabrication of dye-sensitized solar cells (DSSCs).The POR/SPS-G3 co-sensitized solar cell with a TiO 2 photoanode displays enhanced short circuit current, open circuit voltage, and fill factor values (J sc ¼ 16.18 mA cm À2 , V oc ¼ 0.64 V, FF ¼ 0.71, respectively), resulting in an overall power conversion efficiency (PCE) of 7.35%, which is superior to that for the DSSCs based on the individual dyes POR and SPS-G3. This is attributed to the improved light harvesting efficiency of the POR/SPS-G3 co-sensitizing system, which is evidenced by the incident photon-tocurrent efficiency (IPCE) spectrum of the co-sensitized solar cell. Further improvement of the PCE value of the co-sensitized solar cell (up to 8.15%) has been achieved by using a graphene modified TiO 2 (G-TiO 2 ) photoanode, instead of a pure TiO 2 photoanode. Based on dark current measurements and electrochemical impedance spectra (EIS), the increased PCE value of the solar cell with the G-TiO 2 photoanode can be attributed to suppression of charge recombination at the photoanode/dye/ electrolyte interface and enhancement of electron transport in the photoanode. These results are in accordance with the longer electron lifetime exhibited by the G-TiO 2 photoanode.

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