Pyrazol-4-yl-substituted α-nitronyl and α-imino nitroxide radicals in solution and solid states

The synthesis, solution studies, X-ray structures and magnetic properties of two new radical derived pyrazole ligands, based on α-nitronyl and imino nitroxides are reported. The spin distribution on the radicals has been studied in solution using EPR spectroscopy on dilute solutions. In concentrated solutions the radicals form aggregates in solution in which the magnetic interactions have been studied using low-temperature EPR spectroscopy.