Many spacer-containing functional polymers were produced by
modifying beads of (vinyl)polystyrene,
as obtained by free-radical suspension polymerization of a commercial
55:45 divinylbenzene:ethylstyrene mixture, or from commercial sources. Thus, in the
presence of free-radical initiators,
compounds HBr, HPR2, HP(OR)2, and HSR (R =
various alkyl, aryl or acyl, some also containing
further COOH/R, OH/R, SH/R, N(H/R)2 groups) underwent
anti-Markovnikov addition to the
residual vinyl groups. Similar free-radical functionalization with
various HSiR3 also proved feasible
but more difficult. Other products corresponding to formal
anti-Markovnikov addition of H2S,
HSO3
-, HP(OH)2, H2,
HBR2, HOH, and HOSO2R were obtained by other
mechanisms, or after
further modifications. FTIR spectra of the resulting functional
polymers often showed complete
or near-complete disappearance of initial vinyl groups and their
replacement by the expected spacer-supported functionalities. The polymer products were also
characterized by elemental analysis
and solid-state NMR. Many of these functionalized beads, or their
further derivatives upon
functional group modification, could act as stable and effective
solid-phase reagents, catalysts,
sequestering agents, or protecting groups for solid-phase
synthesis.