Characterization of the Chiral Paramagnetic Multispin System Built on a Cyclotriphosphazene Scaffold

Chiral nitroxide–cyclotriphosphazene hybrid compounds such as 2,2-dinitroxide (1a), 2,2,4,4-tetranitroxide (2a), and 2,2,4,4,6,6-hexanitroxide (3a) have been prepared to examine the potentiality for the use of the cyclotriphosphazene framework as a molecular scaffold for elaborating robust, chiral paramagnetic multispin systems. EPR spectroscopic studies of these compounds in solution and in frozen solvent matrixes indicate the existence of appreciable intramolecular electronexchange interactions between two or three neighboring radical moieties disposed on the same side of the cyclotriphosphazene ring. Their bulk paramagnetic properties have also been characterized by magnetic susceptibility measurements.