Synthesis and characterization of poly{hexakis[(methy1)(4-hydroxyphenoxy)]cyclotriphosphazene}

The reaction of methylhydroquinone with hexachlorocyclotriphosphazene in th e presence of a base, 4-picoline, in cyclohexane was investigated. Nuclear magnetic resonance spectroscopy, multiangle laser light scattering, and ele mental analyses were performed on the product and two other related phospha zene materials produced by analogous synthetic routes: poly[hexakis(4-hydro xyphenoxy)cyclotriphosphazene] (1) and hexakis[(3-tert-butyl)(4-hydroxyphen oxy)]cyclotriphosphazene (2). Unlike the data for 2 where the tert-butyl mo iety enforced regiospecific nucleophilic addition, the data for the methylh ydroquinone-substituted cyclotriphosphazene product indicate that the less sterically bulky methyl group provides only limited protection for the adja cent hydroxyl group. The result is the formation of a low molecular weight oligomer, poly(hexakis[(methyl)(4-hydroxyphenoxy)]cyclotriphosphazene) (3), instead of a discrete cyclic trimer species. (C) 2001 John Wiley & Sons, I nc.