O. Jurgens et al., SYNTHESIS AND MAGNETIC CHARACTERIZATION OF METALLOCENE-SUBSTITUTED ALPHA-NITRONYL NITROXIDE RADICALS, Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals, 306, 1997, pp. 249-256
The synthesis acid magnetic characterization of a series of alpha-meta
llocenyl nitronyl nitroxide monoradicals (M = Fe, Ru, Os) are reported
. Intra-and intermolecular magnetic interactions in this series of com
pounds have been studied in detail by ESR spectroscopy and magnetic me
asurements. ESR spectra of monoradicals in dilute solutions under isot
ropic conditions show a small spin density on the metal centers. In th
e solid state, the radicals derived from ferrocene and ruthenocene sho
w a paramagnetic behavior with very weak antiferromagnetic intermolecu
lar interactions, as ascertained from magnetic susceptibility measurem
ents. This behavior is rationalized, for the ferrocene derivative, by
means of its crystal structure.