Coordination-induced polymerization of P═C bonds leads to regular (P─C) polycarbophosphanes

The replacement of carbon in (C─C) chains of polyolefins by phosphorus leads to polycarbophosphanes (P─C) , which may possess unique chemical and physical properties. However, macromolecules with a regular (P─C) chain have never been unambiguously identified. Here, we demonstrate that addition polymerization, a general concept to polymerize olefins, can be extended to P═C double bonds. The polymerization of monomeric 2-phosphanaphthalenes is mediated by copper(I) halides and leads to polycarbophosphanes with an M of 14 to 34 kDa. Each phosphorus is coordinated to Cu(I), which can be easily removed. Unlike long-term durable polyolefins, the metal-free polymers depolymerize rapidly back to monomers under sunlight or ultraviolet irradiation at λ = 365 nm. The monomers can be recycled for repolymerization, demonstrating a cradle-to-cradle life cycle for polycarbophosphanes.