Synthesis of Ordered Polymer by Direct Polycondensation. 7. Ordered Poly(acylhydrazide−amide)

An ordered (−aadcbbcd−) poly(acylhydrazide−amide) was prepared by the direct polycondensation of a pair of symmetric monomers (XabX), 2,5-dimethylterephthalic acid (XaaX) and 4,4‘-(oxydi- p -phenylene)dibutanoic acid (XbbX), with a nonsymmetric monomer (YcdY), 4-aminobenzhydrazide, using the condensing agent diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate ( 1 ). The polymerization was carried out by mixing the dicarboxylic acids, condensing agent 1, and triethylamine (TEA) in NMP for 2 h at room temperature, followed by adding 4-aminobenzhydrazide, yielding the ordered poly(acylhydrazide−amide) with an inherent viscosity of 0.40 dL/g. The authentic ordered polymer was prepared to verify the structure of the ordered polymer. The microstructures of polymers obtained were investigated by 13 C-NMR spectroscopy, and it was found that the polymer had the expected ordered structure. Furthermore, the model reactions were studied in detail to demonstrate the feasibility of polymer formation.