A representative of a new class of conducting oligomer: acetylene-terminated polyaniline

We present the first synthesis of acetylene-terminated polyaniline oligomers (ATPAs) by two chemical methods. One method, a modified Moore—Honzl—Wudl synthesis, involves the condensation of p-phenylenediamine (PDA) with 2,5-dioxo-1,4-cyclohexanedicarboxylic acid, followed by endcapping with 3-ethynylaniline (EA) and subsequent air oxidation. The other, more convenient, method is based on a modified Manassen—Khalif Schiff-base approach involving the condensation of PDA with commercially available 1,4-cyclohexanedione, followed by endcapping with EA and subsequent air oxidation. Both methods give oligomers with molecular weight distributions. The ATPAs have been characterized by FT-IR, UV—Vis, 1H NMR, MS and ESR methods. Brønsted acid doping gives conducting ATPAs (up to 10−2 S/cm). The results of comparative studies of the ATPAs prepared by both methods are presented.