Bisnitroxide Compounds as Paramagnetic Host Molecules

Abstract

We synthesized a 2,2'-bipyridine-bridged t -butyl nitroxide biradical (bpybNO) and a 2,2':6',2"-terpyridine-bridged t -butyl nitroxide biradical (tpybNO) as a paramagnetic host. tpybNO possesses three nitrogen atoms, which facilitates host-guest complexation with metal ions. ESR spectra showed a quintet due to relatively fast exchange coupled bisnitroxide spins. It was also characterized as a biradical solid by means of SQUID measurements. After addition of La salts, the ESR line shapes were changed. We will discuss comparison of the magnetic properties of the pristine host and its complexes.