Assemble And Properties Of Rare Earth Nitroxide Radicals Functional Complexes

The design and synthesis of rare earth complexes with radical is one of the most attractive fields in the molecular-based magnetic materials. In order to investigate the correlation between the structure and magnetic properties, fourteen novel complexes have been synthesized. All their single crystals have been determined by X-ray diffraction technique. They have been characterized by element analyses, IR, TG and variable- temperature magnetic susceptibility. Some magnetic parameters have been evaluated from magnetic measurements and theoretical methods.The thirteen mononuclear RE(III)-radical complexes [RE(hfac)3(NITR)2] are isomorpous, in which the RE(III) ion is eight-coordinated with six oxygen atoms of three hfac anions and two oxygen atoms from two radicals NITR. Magnetic studies show that the spin coupling between the spin carriers in Tb(III) complex is ferromagnetic, while antiferromagnetic interaction exist in Eu(III) complex. The thermal decomposition processes of these complexes are similar.A 1-D complex {[Cu(NIT4Py)2(suc)(H2O)]·3H2O}n(14) has been synthesized. The succinate bridge two Cu(II) ion in a bis-monodentate mode, generate an infinite 1-D chain structure. Furthermore, the chains are connected by O-H···O hydrogen bonds, forming a 2-D networks.Many coordination compounds made of rare earth and nitronyl nitroxide radicals have been studied. Their magneto-structural correlations have been explored and the possible magnetic exchange mechanisms are explained. The thermal properties are also discussed.