Spontaneous polymerization of phenylphosphaethyne

The spontaneous polymerization of phenylphosphaethyne yields mostly saturated oligomers. The absence of high molecular weight macromolecules and detectable end groups is consistent with oligomers formed by a cycloaddition mechanism. The broad molecular weight distribution and greater molecular weight of the oligomers is likely the consequence of the greater steric accessibility to the C-P bond offered by the phenyl group. A presence of head-to-head cycloadducts may explain the thermal instability of the oligomers towards fragmentation with loss of P₄.