UBC Theses and Dissertations
The road to new poly(methylenephosphine)s by the anionic polymerization of P=C bonds Wang, Shuai
Addition polymerization of phosphaalkenes has been successfully used in the preparation of poly(methylenephosphine)s, but the candidate monomers are limited to phosphaalkenes bearing relatively bulky substituents like mesityl group. This thesis presents the investigations on the preparation and anionic polymerization of new phosphaalkene monomers bearing smaller substituents. In Chapter 1, the advantages of synthesizing inorganic polymers by addition polymerization is first introduced. Achievements in the synthesis of poly(methylenephosphine)s by addition polymerization of phosphaalkenes is briefly reviewed, followed by the illustration of the intriguing and challenging aspects of the preparation of phosphaalkenes bearing small substituents. In Chapter 2, studies on the anionic polymerization of XylP=CPh₂ are described. It was shown by the NMR characterization of the polymer obtained and the molecular model built for the polymerization that there was intramolecular H-transfer during the anionic polymerization. This isomerization should account for the slow propagation rate of the anionic polymerization of XylP=CPh₂. In Chapter 3, investigations on the preparation of PhP=CPh₂, o-TolP=CPh₂ and MesP=C(H)Ph by the phospha-Peterson reaction are presented. It was found that PhP=CPh₂ and o-TolP=CPh₂ had the tendency to dimerize and afford 1,2-diphosphetane upon formation. The coordination chemistry of PhP=CPh₂ and o-TolP=CPh₂ is also described with the characterization of W(CO)₄(PhP=CPh₂)₂ by single-crystal X-ray crystallography. The anionic polymerization of "masked phosphaalkenes" is an alternative route to polymers containing phosphorus atoms in the main chain without the use of isolated phosphaalkenes. The development of a facile synthetic pathway to "masked phosphaalkenes" is illustrated in Chapter 4. To conclude, results presented in this thesis pave the road to new poly(methylenephosphine)s by anionic polymerization.
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