Coordination compounds of Cu(II) with the nitroxyl radical 2-acetyl-2,5,5-trimethyl-4-phenyl-3-imidazoline-3-oxide-1-oxyl thiosemicarbazone and its 1-hydroxy derivative

Abstract

1. During the formation of complexes of Cu(II) with 2-acety1-2,5,5-trimethyl-4-phenyl-3-imidazoline-3-oxide-1-oxyl thiosemicarbazone, which has a donor functional group adjacent to the radical center, in methanol, chloroform, CH2Cl2, or acetone, the nitroxyl group of the ligand is reduced to the hydroxylamine. In alkaline solution, on the other hand, in the presence of Cu(II) salts the hydroxylamine group of 2-acety1-2,5,5-trimethy1-4-phenyl-3-imidazoline-1-hydroxy-3-oxide thiosemicarbazone is converted into the nitroxyl. 2. The coordination compound with the nitroxyl radical is diamagnetic, apparently owing to strong antiferromagnetic interaction between the unpaired electrons of the paramagnetic centers arising as a result of coordination of the group by the Cu(II) ion.