CRYSTAL-STRUCTURES AND MAGNETIC-PROPERTIES OF THE P-N-METHYPYRIDINIUMNITRONYL NITROXIDE CATION-RADICAL SALTS, P-MPYNN.I AND P-MPYNN.CLO4

X-Ray crystal analyses and magnetic measurements have been carried out on the p-N-methylpyridinium alpha-nitronyl nitroxide (p-MPYNN) cation radical salts, p-MPYNN.I and p-MPYNN.ClO4. The p-MPYNN molecules are connected by short intermolecular contacts between the NO groups in th e crystal of p-MPYNN.I, while the radical molecules are separated from each other by the ClO4- anions in p-MPYNN.ClO4. The magnetic properti es of p-MPYNN.1 and p-MPYNN.ClO4 are found to be consistent with their crystal structures.