UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The structure and reactivity of poly(methylenephosphine)s Gillon, Bronwyn Hilary

Abstract

The initiation and termination steps of the anionic polymerization of P=C bonds have been modeled. The initiation step was investigated through the stoichiometric reaction of MesP=CPh₂(1) with RL1 (R Me or n-Bu). In each case, the addition was highly regioselective with the formal attack of R at phosphorus to give the carbanion Li[Mes(R)P—CPh₂](R = Me (3a); n-Bu (3b)). To simulate the termination step, carbanions 3a and 3b were quenched in situ with various electrophiles: Mes(Me)P—CPh₂H (4a), Mes(n-Bu)P—CPh₂H (4b), Mes(Me)P—CPh₂Me (6a), Mes(Me)P—CPh₂—P(NEt₂)₂ (7a), Mes(Me)P—CPh₂—SiMe₂H (8a) and Mes(Me)P—CPh₂—SiMe₃ (9a). The first use of MALDI-TOF MS in the study of the products of RLi (R = Me, n-Bu) initiated oligomerization of 1 is reported. The detected linear products R[MesP(=O)-CPh₂]nH with R—P and C—H end-groups are consistent with a chain growth mechanism. The oligomerization was extended to other monomers (MesP=CPhAr, Ar = p-C₆H₄F or p-C₆H₄OMe). The results suggest oligomers undergo fragmentation during MALDI-TOF analysis. The thermal reactions of M(CO)₆ (M = W, Mo, Cr) with polymer n-Bu[MesP-CPh₂]nH (10) and its model compound 4a are reported. IR was primarily used to determine the success of metal coordination in the polymer. EDXISEM and GPC-LLS were used to determine metal content of the materials. Most metallation was modest (>10%), however, as much as 20% was attained with Mo. The phosphorus-containing polymer 10 was found to be an effective ligand for gold(l) to afford n-Bu[MesP(AuCl)—CPh₂]nH 11, a new class of macromolecule with high gold content. The prepared model compound MeMesP(AuCI)—CPh₂H 12 was characterized by X-ray crystallography and NMR spectroscopy. Block copolymers containing phosphorus atoms in the backbone were prepared and metallated with gold(l). The living polymerization of isoprene (I) and then phosphaalkene I affords block copolymers PIm-b-[MesP-CPh₂]n (13a: m = 308, n = 46; 13b: m = 222, n = 77). Treating PIm-b-[MesP-CPh₂]n with (tht)AuCI results in gold-containing macromolecules [Pl]mb MesP(AuCl)-CPh₂]n (14a and 14b). Upon dissolution in a polyisoprene selective solvent (n heptane), the metallated block copolymers assembled into micelles (14a: spherical; 14b: worm-like). The solution self-assemblies were examined by TEM and DLS.

Item Media

Item Citations and Data

License

Attribution-NonCommercial-NoDerivatives 4.0 International

Usage Statistics