Radical Copolymerization of a Phosphaalkene with Styrene: New Phosphine‐Containing Macromolecules and Their Use in Polymer‐Supported Catalysis

Abstract

Since Beckers synthesis of the first stable phosphaalkene in 1976, [1] these compounds, which contain a P=C bond and were once considered exotic, now constitute a major branch of phosphorus chemistry. Applications for these compounds are even being developed.[2-4] The ability of P = C bonds, in many instances, to "copy" the well-established chemistry of isolobal C=C bonds has attracted considerable attention. [2, 3a, d] In molecular chemistry, the remarkable analogy between phosphaalkenes and alkenes is evidenced by phospha variants of a number of reactions, including 1,2-addition, [4+2]cycloaddition, Peterson and Wittig olefination, h 2 coordination to metal centers, and Cope and allylic rearrangements. One of the most important reactions of C = C bonds is the addition polymerization of olefins, which is used to produce many commodity polymers. The absence of an analogous polymer chemistry for P=C bonds prompted us to investigate addition polymerization as a potential route to new phosphine polymers. We recently reported the first addition polymerization of the phosphaalkene 1[5] (Mes = 2,4,6-trimethylphenyl) to give the poly(methylenephosphine) 2 (M w % 10 4 g mol À1 by GPC versus polystyrene), an alternating PÀC polymer. [6]

Isomerization Polymerization of the Phosphaalkene MesPCPh2: An Alternative Microstructure for Poly(methylenephosphine)s

“…Our studies showed that MesPCPh 2 ( 1 ) and related monomers polymerize in the presence of radical or anionic initiators to afford poly(methylenephosphine) (Scheme ) 6. The living anionic polymerization of 1 permits the formation of functional phosphine‐containing block copolymers,7, 8 and the radical‐initiated copolymerization of 1 with styrene affords random copolymers 9…”

CO2 Cycloaddition Reactions Catalyzed by an Ionic Liquid Grafted onto a Highly Cross‐Linked Polymer Matrix

“…Polymeric materials are very attractive supports of catalysts as a result of some unusual advantages. [4] In recent years, immobilization of ILs onto polymers has been studied. For example, Carlin and Fuller prepared a catalytic membrane for heterogeneous hydrogenation which was composed of ILs and poly(vinylidene fluoride)-hexafluoropropylene copolymers with the incorporation of Pd on activated carbon.…”

Flammability properties of paper coated with poly (methylenephosphine), an organophosphorus polymer

“…The anionic polymerization of phosphaalkene ( PA ) using n ‐BuLi (0.015 equiv) as initiator afforded polymer PMP in high yield (91%) (Scheme ). Compared with small scales (approximately 1 g of PA ) used in previous polymerization experiments of PA , the present work illustrates that the anionic polymerization of PA is amenable to moderate scale‐up (16.3 g of monomer) with n ‐BuLi (1.5 mol%), which is the largest scale reported for the polymerization of PA . Analysis of the isolated pale yellow polymer by triple detection GPC‐MALS revealed a modest molecular weight ( M n = 27,000 g mol −1 ) and polydispersity index (PDI = 1.47).…”

“…As part of our program to develop new functional polymers containing phosphorus atoms in the main chain, we have been investigating the addition polymerization of the PC bond in phosphaalkenes (Scheme ) . Our work has shown that PC bonds, analogous to the CC bonds of olefins , may be polymerized using radical or anionic methods of initiation and that random and block copolymers are accessible containing phosphine functionalities.…”