Novel thermally stable poly(amine hydrazide)s and poly(amine-1,3,4-oxadiazole)s for luminescent and electrochromic materials

We describe the preparation, characterization, and luminescence of four novel electrochromic aromatic poly(amine hydrazide)s containing main-chain triphenylamine units with or without a para-substituted NN-diphenylamino group on the pendent phenyl ring. These polymers were prepared from either 4,4'-dicarboxy-4% N,N-diphenylaminotriphenylamine or 4,4-dicarboxytriphenylamine and the respective aromatic dihydrazide monomers via a direct phosphorylation polycondensation reaction. All the poly(amine hydrazide)s were amorphous and readily soluble in many common organic solvents and could be solution-cast into transparent and flexible films with good mechanical properties. These poly(amine hydrazide)s exhibited strong ultraviolet-visible absorption bands at 346-348 nm in N-methyl-2-pyrrolidone (NMP) solutions. Their photoluminescence spectra in NMP solutions or as cast films showed maximum bands around 508-544 and 448-487 nm in the green and blue region for the two series of polymers. The hole-transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. All obtained poly(amine hydrazide)s and poly(amine-1,3,4-oxadiazole)s exhibited two reversible oxidation redox couples at 0.8 and 1.24 V vs. Ag/AgCl in acetonitrile solution and revealed excellent stability of electrochromic characteristics, changing color from original pale yellow to green and then to blue at electrode potentials of 0.87 and 1.24 V, respectively. (c) 2005 Wiley Periodicals, Inc.