Syntheses, structures, and magnetic characterizations of five Mn(II) and Co(II) complexes based on 2,6-Pyridyl-substituted nitronyl and imino nitroxide radical

• The reaction of pyridine nitroxide biradical with M(hfac)2·XH2O (M = MnII, CoII) were investigated.
• These reactions were found to be related to the type of the metal ion employed.
• Redox reactions involve in the synthesis process of the complexes.
• They all exhibited antiferromagnetic interactions at high temperature range.
• They exhibit different magnetic behaviors at low temperature because of the intermolecular interactions.

The reaction of biradical 2,6-NITpy (1) (2,6-NITpy = 2,6-bis (3′-oxide-1′-oxyl-4′,4′,5′,5′-tetramethylimidazolin-2′-yl) pyridine), 2-NIT-6-IMpy (2) (2-NIT-6-IMpy = 2-(3′-oxide-1′-oxyl-4′,4′,5′,5′-tetramethylimidazolin-2′-yl)-6-(1′-oxyl-4′,4′,5′,5′-tetra-methylimidazolin-2′-yl) pyridine), or 2,6-IMpy (3) (2,6-IMpy = 2,6-bis(1′-oxyl-4′,4′,5′,5′-tetra-methylimidazolin-2′-yl) pyridine) with M(hfac)2·XH2O (M = MnII, CoII) were investigated. These reactions were found to be related to the type of the metal ion employed. Interestingly, redox reactions involve in the synthesis process of the complexes. Structures of the five complexes were elucidated by X-ray analysis, and their magnetic properties were investigated in detail. The temperature dependence of χMT for all the five complexes at high temperature range exhibited antiferromagnetic interactions between the transition metal spin (MnII or CoII) and the nitroxide radical spin. At low temperature, the χMT curves exhibit different magnetic behaviors because of the different crystalline fields and intermolecular interactions.

Five novel complexes based on nirtronyl and imino nitroxide radicals were obtained, interesting redox reactions involve in the synthesis process of the complexes. Structures of the five complexes were elucidated by X-ray analysis, and their magnetic properties were investigated in detail.Figure optionsDownload as PowerPoint slide