Single-Molecule Magnet Properties in 3d4f Heterobimetallic Iron and Dysprosium Complexes Involving Hydrazone Ligand

The reaction between the ((E)-N'-(2-hydroxy-3-methoxybenzylidene)pyrazine-2-carbohydrazide) (H(2)opch) ligand and the metallo-precursor [Dy(hfac)(3)].2H(2)O led to the formation of an homometallic coordination complex with the formula [Dy-2(hfac)3(H2O)(Hopch)(2)][Dy(hfac)(4)] (1). In presence of both [Dy(hfac)(3)] 2H(2)O and the Fe(II) salt, the heterobimetallic tetranuclear [FeDy3(hfac)(8)(H2O)(2)(opch)(2)] (2) was isolated, while the addition of the co-ligand 1,2-Bis(2-hydroxy-3-methoxybenzylidene) hydrazine (H(2)bmh) led to the formation of two heterobimetallic tetranuclear complexes with the formula [Fe3Dy(hfac)(6)(opch)(2)(H(2)bmh)] C6H14 (3) C6H14 and [Fe2Dy2(hfac)(7)(opch)(2)(H(2)bmh)] 0.5C(7)H(16) (4) 0.5C(7)H(16). Single crystal X-ray diffraction and dc magnetic investigation demonstrated that 3 and 4 involved the iron center in the +II and +III oxidation states. Dynamic magnetic measurements highlighted the single-molecule magnet behavior of 1 and 2 in a zero applied dc field primarily due to the ferromagnetic interactions taking place in these compounds.