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Series of dyes containing a cyanovinyl entity in the spacer have been developed and characterized. Dye-sensitized solar cells (DSSCs) using the dyes as the sensitizers exhibited good efficiencies ranging from 3.48−4.92%, which reached 45−70% with respect to that of an N719-based device fabricated under similar conditions. In general, better DSSC performances are observed with molecules having a shorter distance between the internal cyanovinyl entity and the amine donor. Computational analysis indicated that the cyanovinyl entity may behave as a charge trap, especially in the long molecules studied, where the cyanovinyl group is away from the electron-donating amine by two or more aromatic groups. A positive correlation is observed between the theoretically calculated product of oscillator strengths and the charge shift at the cyanoacrylic acid group and the measured short-circuit current in DSSCs. Therefore, it is likely that the charge-trapping in the cyanovinyl entity reduces the electronic interaction between the dye and the attached TiO2 and, therefore, compromises the DSSC performance.

Ruthenium σ-acetylides containing a dangling pyridine were synthesized from the reactions of CpRu(L)2Cl (L = PPh3, 1/2 (C5H4PPh2)2Fe) with 4-ethynylpyridine, (E)-1-(4-ethynylphenyl)-2-(4-pyridyl)ethylene, or 4-(ethynylphenyl)(4-pyridyl)acetylene in the presence of NH4 +PF6 - followed by deprotonation with a base. The dangling pyridine can be protonated, methylated, or ligated to tungsten carbonyl fragments. The ruthenium donor to the pyridinium acceptor charge-transfer absorption appears at longer wavelength as the conjugation chain becomes longer. The quadratic hyperpolarizabilities of the methylated derivatives were determined using the hyper Rayleigh scattering method. X-ray analysis was employed to examine the structure of the dinuclear complex Ru(C⋮CC5H4N{W(CO)4(PPh3)})(η2-dppf)(η5-C5H5) (dppf = 1,1‘-bis(diphenylphosphino)ferrocene).