Mononuclear Transition Metal Cymantrenecarboxylates as Precursors for Spinel-Type Manganites

Novel mononuclear cymantrenecarboxylate complexes of transition metals, [Co(H O) ](CymCO ) ·4H O (Cym = (η -C H )Mn(CO) ) ( ), [Ni(H O) ](CymCO ) ·4H O ( ), [Zn(H O) ](CymCO ) ·4H O ( ), [Co(CymCO ) (imz) ] (imz = imidazole, ), [Co(CymCO ) (bpy) ]·2PhMe (bpy = 2,2'-bipyridyl, ), [Ni(CymCO )(bpy) (H O)][CymCO ]·0.5MePh·2H O ( ), [Cu(CymCO ) (imz) ] ( ), and [Cu(CymCO ) (bpy)(H O)] ( ), were obtained and characterized by single-crystal X-ray analysis. Complexes - are isostructural. Magnetism of the Co complexes , , and was studied; it was shown that they exhibit the properties of field-induced single-molecule magnets with magnetization reversal barriers (ΔE/k ) of 44, 13, and 10 K, respectively. Thermal decomposition of complexes - was studied by means of DSC and TGA methods. The final products of thermolysis of - in air, according to powder XRD data, are the pure spinel phases MMn O ; for the cases of copper complexes, the mixtures of CuMn O and CuO were found in the products.