Studies on polyyne polymers containing transition metals in the main chain. VII. Synthesis and characterization of palladium‐polyyne polymers

Metal‐polyyne polymers consisting of palladium and conjugated acetylenic systems, magnified image where PD and R represent the —Pd(PBu3)2—moiety and alkyl groups, respectively, were prepared by polycondensation between palladium chlorides and α,ω‐diethynyl compounds in amines using a catalytic amount of cuprous iodide. The molecular weights of the polymers formed were greatly affected by the basicity of the amines and the addition of free phosphines to the polymerization system. Under the optimum conditions, i.e., in the presence of CuI and PBu3 (in molar ratio 1/4) in piperidine at room temperature, polymer Ia (R1 = R2 = H) having M̄w = 29,000 was obtained.