S. Bruckner et al., CRYSTAL-STRUCTURE OF THE ISOTACTIC ALTERNATE COPOLYMER BETWEEN CARBON-MONOXIDE AND STYRENE, Macromolecules, 29(5), 1996, pp. 1535-1539
The crystal structue of a highly isotactic optically active alternatin
g styrene-carbon monoxide copolymer, obtained with a chiral cationic P
d(II) bioxazoline complex, is determined and refined from powder X-ray
diffraction data with the Rietveld method. The unit cell is monoclini
c, P2(1) space group, with a = 8.367 Angstrom, b = 7.574 Angstrom (cha
in repeat), c = 5.47 Angstrom, beta = 110.0 degrees, and Z = 2 monomer
ic unis with a density of 1.32 g/cm(3); The observed chain conformatio
n has a repeat period almost identical to that observed in syndiotacti
c copolymers in spite of the different symmetry connecting the monomer
ic units, s(2/1) instead of tc. The different symmetry connecting the
monomeric units along the chain influences significantly the reciproca
l orientation of the phenyl groups within each chain and between diffe
rent chains.