Synthesis of Non-Kekule Type π-Conjugated Polymers and Co-operative Multiple-Spin Alignment

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Objectives of this research are the synthesis of π-conjugated polymers bearing pendant radical groups on every monomer unit, which are substituted on the polymer backbone to satisfy a π-conjugated but non-Kelule structure, and the study on strong and through-bond ferromagnetic exchange interaction between and alignment of the multiple spins of the pendant radicals.(1) Bromostyrene dirivatives were polycondensated with a Pd-phosphine catalyst to yield π-conjugated star-shaped or hyperbranched poly (4-phenoxyl-1, 2-phenylenevinylene) s. SQUID and pulsed ESR measurements revealed the spin-alignment, e. g., with S = 10/2.(2) Linear, acyclic, and cyclic poly (phenoxy-phenyleneethynylene) s were synthesized by the polycondensation of the iodostyrene derivatives with a Pd/Cu catalyst. The cyclic and conjugated one was an effective spin pathway.(3) Diphenylaminium cation radical was introduced as a spin source to poly (4-substituted 1, 2-phenylenevinylene) to realize both a sufficient ferromagnetic interaction and chemical stability even at room temperature. Stability of the multiplet ground state was significantly large to first give a highspin and durable organic polymer.