Tetra(4‐hexylphenyl) [3]‐ and [5]Cumulenes

The synthesis of [3]- and [5]cumulenes bearing 4-hexylphenyl endgroups, [3]PhHex and [5]PhHex, has been developed. The incorporation of alkyl groups is designed to enhance film formation by improving solubility. Although tetraaryl[3]cumulenes are typically quite stable, the head-to-tail dimerization of [3]PhHex is observed after prolonged storage under ambient conditions, and the dimer is characterized crystallographically. The crystallographic analysis of [5]PhHex in comparison with other tetraaryl[5]cumulenes demonstrates changes in packing as a function of increasing size of the alkyl group. Preliminary characterization of field-effect transistors fabricated with [3]PhHex, in comparison with the parent compound tetraphenyl[3]cumulene [3]Ph, shows poorer performance for [3]PhHex and emphasizes the need to optimize film-forming protocols for new cumulenic semiconductors.