Terminal solvent effects on the anisotropy barriers of Dy 2 systems.

A family of three dinuclear dysprosium complexes have been successfully synthesized and studied in terms of their magnetic properties. Complexes 1 and 2 share the formula [Dy2 (ovph)2 Cl2 (solvent)2 ], where H2 ovph = pyridine-2-carboxylic acid [(2-hydroxy-3-methoxyphenyl)methylene] hydrazide, and solvent = DMF (1), i-PrOH (2), while complex 3, [Dy2 (ovph)2 Cl2 (H2 O)3 (EtOH)], exhibits differences in terms of the identity and number of coordinated solvent molecules. Thus, we investigate the impact of terminally bonded solvent molecules on the slow relaxation dynamics of {Dy2 } SMMs, a parameter which can sometimes be overlooked in the quest to attain higher energy barriers. Notably, the exchange of DMF for i-PrOH, both of which coordinate through a single oxygen atom, results in a near 2-fold increase in Ueff , from 58 to 98 K, for 1 and 2, respectively.