Functionalized arylacetylene oligomers for Organic Thin-Film Transistors (OTFTs)

The preparation of arylacetylene oligomers comprising of three repeating phenylene ethynylene units containing para-substituted electron-donating or electron-withdrawing substitutents was analyzed. The compounds were prepared with product yields up to 91% using a synthetic strategy based on a simple iterative and convergent Pd/Cu-coupling and desilylation protocol. The preparation included treatment of the respective trialkylsilyl iodide and terminal arylalkyne starting material in the presence of PdCl ₂(PPh₃)₂ and CuI at room temperature. It was observed that the relative planar configuration of arylacetylene moieties along the molecules was important for the on-off switch stage.