Cross-Dehydrogenative Coupling (CDC) as Key-Transformations to Various D-π-A Organic Dyes: C-H/C-H Synthetic Study Directed toward Dye-Sensitized Solar Cells Applications.

A variety of push-pull type organic dyes are facilely synthesized through the most atom-economical C-H/C-H dehydrogenative coupling reactions. After comprehensive synthetic optimizations, a broad substrate scope is achieved and functional groups, such as ester, ketone, nitrile, nitro, and triazene are well tolerated. The sensitive aldehyde group required for the conversion into anchoring groups for DSSCs applications is also compatible under present oxidant-containing reaction conditions. Based on this optimum C-H/C-H coupling approach, three new organic sensitizers are readily prepared and submitted to solar cell device fabrications, giving the power conversion efficiency (PCE) up to 4.85%. This work constitutes the first example that connects high atom-efficiency C-H/C-H green catalysis with dye-sensitized solar cell applications.