Synthesis of conjugated polymer consisting of three-component aromatic units via two-step cross-dehydrogenative-coupling reactions

A Pd-catalyzed two-step cross-dehydrogenative-coupling sequence enabled the synthesis of a pi-conjugated polymer consisting of three-component aromatic units, without the use of prefunctionalized starting substrates. When using 1,2,4,5-tetrafluorobenzene as the starting substrate, the cross-coupling reactions proceeded efficiently and the undesired homocoupling reaction was suppressed, producing a new donor-acceptor pi-conjugated polymer. The introduction of a 4H-cyclopenta[2,1-b:3,4-b']-dithiophenediyl unit between the tetra-fluorophenylene units enhanced coplanarity along the polymer chain, thus lowering the energy gap of the polymer. The obtained polymer was also evaluated for use as an emitting material in organic light-emitting diodes.