| Three classes of polyaniline (PANI) derivatives have been prepared using Pd-catalyzed C-N coupling reactions: linear meta-PANI, hyperbranched meta-PANI, and linear ortho-co-para-PANI. Regioregular meta-PANI was prepared independently by the palladium-catalyzed condensation of 3-bromoaniline (polymer 3a) and from the copolymerization of 1,3-dibromoaniline with 1,3-phenylenediamine (polymer 3b). Polymers 3a and 3b have GPC determined molecular weights in THF of MW = 6300 (PDI = 1.2) and M W = 8800 (PDI = 1.2), respectively, and they exhibit IR and NMR spectral data that are consistent with regioregular meta-substitution. At low temperature, after oxidation, these materials showed limited coupling between adjacent spins (S = 1). Attempts to prevent multiple couplings at N by introducing a protecting group proved ineffective.; 1,3,5-Hyperbranched PANI was prepared by the palladium catalyzed polycondensation of two AB2 monomers: 3,5-dibromoaniline (polymer 15a) and 1,3-diamino-5-bromobenzene (polymer 15b). The 1H NMR and 13C{lcub}1H{rcub}-NMR data for hyperbranched polymer 15a (MW = 22 000 in NMP) are consistent with a 1,3,5-hyperbranched structure with 40% branching. Polymer 15b exhibits more complex spectral data than 15a and is presumed to be cross-linked. Oxidation of 15a produced a material with improved magnetic properties relative to the linear polymer.; A new ortho-co-para-PANI copolymer was also prepared in order to allow for the introduction of solubilizing substituents on the conducting polymer backbone without concomitant loss of conductivity. Palladium catalyzed polycondensation of preassembled trimeric macromonomers gave 5p,o-PANI, a new PANI derivative, containing five para-substituted aniline rings for every one ortho-substituted aniline ring. The regioregularity of 5p,o-PANI (MW = 24 000, GPC in NMP) was established using 1H NMR, 13C{lcub}H{rcub}-NMR, and IR spectroscopy. Analogous to p-PANI, the 5p,o-PANI exhibited three distinct oxidation states. The conductivity of blends of 5p,o-PANI and PVC was 0.01 S/cm and was on the same order of magnitude as the conductivity of PANI films (0.05 S/cm) prepared under the same conditions. |
