Synthesis and characterization of novel Schiff‐base polyamides from copper/benzil bisthiosemicarbazone complexes

A new copper‐containing Schiff‐base diamine, benzil bis(thiosemicarbazonato)copper(II) (CuLH₄), was synthesized in two steps from benzil bisthiosemicarbazone (LH₆). The ligand LH₆ and the complex CuLH₄ were characterized with Fourier transform infrared spectroscopy, ¹H‐NMR, and elemental analysis. CuLH₄ was used to prepare novel polyamides. The low‐temperature solution polycondensation of the complex CuLH₄ with various aromatic and aliphatic diacid chlorides afforded copper‐containing Schiff‐base polyamides with inherent viscosities of 0.25–0.36 dL/g in N,N‐dimethylformamide (DMF) and 0.75 dL/g in H₂SO₄ at 25°C. The polyamides were generally soluble in a wide range of solvents, such as DMF, N,N‐dimethylacetamide, tetrahydrofuran, dimethyl sulfoxide, ethyl acetate, tetrachloroethane, hexamethylene phosphoramide, N‐methylpyrrolidone, and pyridine. Thermal analysis showed that these polyamides were practically amorphous, decomposed above 270°C, and exhibited 50% weight loss at and above 400°C. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008