Modulating Magnetic Dynamics of Dy2 System through the Coordination Geometry and Magnetic Interaction.

Two new dinuclear dysprosium compounds, [Dy2(HL1)2(PhCOO)2(CH3OH)2] (l) and [Dy2(L2)2(NO3)2-(CH3OH)2]-2CH3OH-4H2O(2), have been assembled through applying two ligands with different coordination pockets. The different features of ligands H3L1 and H2L2 result in the distinct coordination geometry of the metal ions in their respective structures. The Dy ions of complexes 1 and 2 were linked by the alkoxide- and hydrazone-O, and display the hula hoop-like and the broken hula hoop-like coordination geometry, respectively. Consequendy, these two compounds show distinct magnetic properties. Complex 1 behaves as a single molecule magnet (SMM) with rather slow quantum tunneling rate (... > 274 ms), while no SMM behavior was observed for complex 2. In addition, the comparison of the structural parameters among the similar Dy2 SMMs with hula hoop-like geometry reveals the significant role played by coordination geometry and magnetic interaction in modulating the relaxation dynamics of SMMs. [ABSTRACT FROM AUTHOR]