Preparation and magnetic interaction of a polymer pendent nitroxide with a bulky protecting group

In order to clarify the origin of antiferromagnetic nature of polyphenylacetylene pendant polyradicals, a phenylacetylene-polymer I using a nitroxide with a bulky protecting group as a spin-building block was synthesized and its magnetic behavior was studied by means of SQUID and EPR. The antiferromagnetic behavior observed in both SQUID and EPR-matrix experiments indicates that antiferromagnetic nature is ascribed to the probable large torsion angle(s) of the polymer main chain.