Diruthenium compounds of thiol capped oligo(phenyleneethynyl) ligand: Synthesis and characterization

Reactions between Ru2(DMBA)4(NO3)2 and OPEn-S-TMSE ligand under weak base conditions afford trans-Ru2(DMBA)4(OPEn-S-TMSE)2 compounds, where DMBA is N,N′-dimethylbenzamidinate, TMSE is trimethylsilylethylene, and OPEn are –Ctriple bond; length of mdashCC6H4– (1), –Ctriple bond; length of mdashC(2,5-(CH3O)2C6H2)–(Ctriple bond; length of mdashCC6H4)– (2) and –(Ctriple bond; length of mdashCC6H4)–Ctriple bond; length of mdashC(2,5-(CH3O)2C6H2)–(Ctriple bond; length of mdashCC6H4)– (3). Molecular structures of compounds 1 and 2 were determined by X-ray diffraction, which revealed the extended rigid rod topology and coplanarity of phenyleneethynye units in 1 and 2. Electrochemical and optical energy gaps of compounds 1–3 were estimated to be 1.57 eV and ca. 1.43 eV, respectively, from voltammetric and absorption spectral measurements.