Preparation, Crystal Structures And Magnetic Properties Of The Metal Complexes With Nitronyl Nitroxide Radical

The synthesis and study of metal complexes with nitronyl nitroxide radical has been one of the most attractive fields in the molecular-based magnetic materials. Focused on this topic, thirty-two new complexes have been synthesized by using metal ions and nitronyl nitroxide radicals as spin carriers in this work. The structures of thirty have been determined by X-ray crystallographic methods and characterized by elemental analyses, IR and DC/AC magnetic measurements.1. Six iron(Ⅱ) complexes were synthesized by using pyridyl-substituted nitroxide radicals as spin carriers, incorporating NCS", N(CN)2- as co-ligands and 4,4-bipyridine,4,4-azopyridine as bridging ligands. The radical ligands in five complexes were reduced. The magnetic property studies indicate that the existence of antiferromagnetic coupling in the complexes.2. Four ion-pair complexes were synthesized by using M(mnt)22- anions and m-or p-MPYNN cations. The magnetic properties are studied and the results show that the complexes exhibit weak antiferromagnetic intermolecular interactions. In complex [(m-MPYNN)2Ni(mnt)2·(THF)3], the m-MPYNN molecules are present as a centrosymmetric dimer, and the magnetic property behavior can "be described by a singlet-triplet model of S=1/2 dimers.3. Twenty-two lanthanide complexes with different radical ligands have been synthesized and their magnetic properties are investigated. The magnetic slow relaxation behaviors are observed in complexes [Tb(hfac)3(NITPhSCH3)2], [Tb(hfac)3NIT-2Py]·(0.5C7H]6), [Dy(hfac)3NIT-2Py]·(0.5C7H16), [Tb(hfac)3IM- 2Py] and [Tb(hfac)3IM-2thz], suggesting single-molecule magnets, which are the first SMMs containing chelate nitroxide radical and lanthanide ions. 1D complex [Tb(hfac)3(NITPhSCH3)]n shows SCM behaviors.