Group 14 effects in alkynyl acene small molecule semiconductors

Silyl ethynyl groups have become commonplace in functionalizing organic semiconductors, where they improve solubility and stability. The identity of the side chain also dictates the molecular organization in the solid state, and thus heavily influence bulk material properties such as charge mobility. Germanium-containing side chains show the same propensity to form favorable solid state packing motifs, but carbon analogs remain mostly unexplored. Here we present a general synthesis of carbon alkynes, changes in molecular properties of acenes functionalised with these alkynes, and a rich variety in crystal packing motifs that have rarely been observed with silicon or germanium side chains.