Single-Molecule Magnet Properties in 3 d 4 f 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 (H 2 O)(Hopch) 2 ][Dy(hfac) 4 ] ( 1 ). In presence of both [Dy(hfac) 3 ] 2H 2 O and the Fe(II) salt, the heterobimetallic tetranuclear [FeDy 3 (hfac) 8 (H 2 O) 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 [Fe 3 Dy(hfac) 6 (opch) 2 (H 2 bmh)] C 6 H 14 ( 3 ) C 6 H 14 and [Fe 2 Dy 2 (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.