Synthesis and structural characterization of a C₄ cumulene including 4-pyridylidene units, and its reactivity towards ammonia-borane.

A novel type of C4 cumulene derivative featuring 4-pyridylidene units has been synthesized. X-ray diffraction analysis revealed the presence of consecutive C=C double bonds in the C4 backbone as well as the quinoidal pyridylidene structure. This C4 cumulene derivative readily reacted with ammonia-borane, which resulted in transfer hydrogenation of the central C=C double bond.