Phosphaalkene-oxazoline copolymers with styrene as chiral ligands for rhodium(I)

The radical-initiated copolymerization of phosphaalkene-oxazoline, MesPvC(Ph)CMe(2)Ox [1, Ox = CNOCH(iPr)CH2] with different loadings of styrene affords poly(methylenephosphine-co-styrene) s [2a (1 : S = 1 : 2): M-w = 7400 g mol(-1), PDI = 1.1; 2b (1 : S = 1 : 5): M-w = 18 000 g mol(-1), PDI = 1.2; 2c (1 : S = 1 : 10): M-w = 16 000 g mol(-1), PDI = 1.3]. Copolymers 2a-2c are demonstrated as viable macromolecular ligands for rhodium(I). By comparison with the crystallographically characterized model P, N-bidentate complex, [Mes(Me) P-CH(Ph) CMe(2)Ox center dot Rh(cod)] BF4, the polymer complexes [2 center dot Rh(cod)]BF4 were prepared. The macromolecular metal complexes were characterized by GPC {for [2a center dot Rh(cod)]BF4: M-w = 14 000 g mol(-1), PDI = 1.2}, UV/Vis spectroscopy, H-1, C-13 and P-31 NMR spectroscopy. Integration of the P-31 NMR spectra of mixtures of 2 and [Rh(cod)(2)]BF4 permitted the determination of the mol% of incorporation of monomer 1 in copolymer 2 (2a: 17%; 2b: 5%; 2c: 4%). These results compared favorably with those determined by elemental analysis (2a: 17%; 2b: 6%).