Coordination-induced polymerization of P═C bonds leads to regular (P─C) <sub><i>n</i></sub> polycarbophosphanes.

Mei, Yanbo; Gamboa-Carballo, Juan José; Bao, Yinyin; Wu, Na; Le Corre, Grégoire; Grützmacher, Hansjörg · Sci Adv · 2021

basic_science · Level V

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Abstract

The replacement of carbon in (C─C) <sub><i>n</i></sub> chains of polyolefins by phosphorus leads to polycarbophosphanes (P─C) <sub><i>n</i></sub> , which may possess unique chemical and physical properties. However, macromolecules with a regular (P─C) <sub><i>n</i></sub> 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 <i>M</i> <sub><i>n</i></sub> 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.