Ruthenium-complex-catalysed de-ammonification polycondensation of aromatic diamines

Abstract

This study explores a pioneering catalytic reaction to obtain functional polymers and valuable byproducts. Using RuCl₂(PPh₃)₃ as a catalyst activates the C–N and N–H bonds in aromatic diamines, when combined with 1,4-butynediol. This activation initiates de-ammonification polycondensation, resulting in aromatic polyamines with a pyrrolyl end group and ammonia as a byproduct. The ammonia generated during the polycondensation process can be captured in cold water. The generation of ammonia during polycondensation was confirmed by UV-vis spectroscopy using the Nessler's reagent method. Subsequently, the aromatic polyamines were further functionalised via polymer reactions with 1,4-butanesultone and butyl isocyanate in the NH group. This yielded products with pendant sodium N-butylsulfonate and N-butylamide groups, respectively. The former exhibited a single-ion conductivity. Potential reaction mechanisms involving Ru-catalysed N–H and C–N bond activation in AD, along with the formation of terminal pyrrolyl groups, were investigated using density functional theorycalculations and ²H NMR spectroscopy.