Magnetic and optical characterization of poly(ethynylbenzene) with pendant nitroxide radicals

The magnetic susceptibility measurements show that the polyradical [CH=C(Ph[tBu][NO . tBu])] n shows no appreciable ferromagnetic interactions among the spins in spite of the high spin concentration of the polyradical. This may be explained in terms of the twisted conformation of the nitroxide polyradical which prevents the large delocalization/polarization of the spin to the polyene backbone