A propene-substituted cyclotriphosphazene: synthesis, characterization and polymerization

Abstract

The elimination reaction of the sulfonium-substituted chlorocyclotriphosphazene N ₃ P ₃ Cl ₄ Pr ⁱ (CMe ₂ OSO ₂ Me) with 1,8-diazabicyclo[5.4.0]undec-7-ene afforded a new olefin-substituted chlorocyclotriphosphazene, N ₃ P ₃ Cl ₄ Pr ⁱ (CMe CH ₂ ), and an ansa derivative with formula N ₃ P ₃ Cl ₃ Pr ⁱ (CMe ₂ CHCMeO). The crystal structures of the three compounds were determined. The sequence of N–P bond lengths in the molecules can be explained from the difference in group electronegativity of the phosphorus centres. For N ₃ P ₃ Cl ₄ Pr ⁱ (CMe ₂ OSO ₂ Me) two crystallographic independent molecules are present in the asymmetric unit. In N ₃ P ₃ Cl ₃ Pr ⁱ (CMe ₂ CHCMeO) the bridge between two phosphorus atoms compresses the inorganic ring, which is reflected in a large deviation of 0.563(2) Å of one of the N atoms from the least-squares plane through the remaining ring atoms. This distortion is accompanied by a contraction of the non-bonded P · · · P distances. The propene derivative has been used in radical copolymerization with methyl methacrylate and styrene. A maximum incorporation of 18 mol % was achieved with styrene as comonomer.