Solvent and Reagent Accessibility within Oligo(ethylene glycol) Ether [PEG] Cross-Linked Polystyrene Beads

α,ω-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.