SYNTHESIS AND POLYMERIZATION OF A BULKY STYRENIC MONOMER AS AN IN-CHAIN KNOT FOR POLYROTAXANES

-[Tris(p-t-butylphenyl)methyl]phenoxymethylstyrene (10) was prepared a s a mixture of meta and pala isomers via Williamson ether synthesis fr om vinylbenzyl chloride. Monomer 10 polymerizes smoothly under free-ra dical conditions. Under anionic polymerization conditions, nucleophili c attack at the benzylic position displaces the substituted phenoxide ion; by using an excess of n-butyllithium, however, a polymer of compl ex structure, high molecular weight and polydispersity of 2.2 was form ed. On the basis of its steric bulk and polymerizability, new monomer 10 is therefore a useful in-chain 'knot' or 'stopper' for polyrotaxane synthesis using free-radical techniques, but not via anionic methods.