Solvent and reagent accessibility within oligo(ethylene glycol) ether [PEG] cross-linked polystyrene beads

alpha,omega-Bis-4(vinylbenzyl) ethers of mono-, di-, tetra-, and hexa(ethylene glycol) were used as cross-linkers in polystyrene beads to examine the influence of glycol tether length and % incorporation upon polymer swelling and reagent diffusion. Swelling of 2, 10, and 20% cross-linked poly{styrene-co-[oligo(ethylene glycol) bis(4-vinylbenzyl)ether]} (PS -PEG) beads was determined to be higher or comparable to 2% cross-linked poly[styrene-co-divinylbenzene] (2% PS-DVB) beads. Fluorescence quenching of polymer-bound dansyl groups by Et3O . BF4 indicated that the most rapid intraresin diffusion of this electrophilic reagent occurred in toluene. PS-PEG beads exhibited faster quenching than 2% PS-DVB in poor swelling solvents but were slower to quench than 2% PS-DVB in toluene.