Peripheral site modification in a family of dinuclear [Dy 2 (hynad) 2-6 (NO 3 ) 0-6 (sol) 0-2 ] 0/2- single-molecule magnets bearing a {Dy 2 (μ-OR) 2 } 4+ diamond-shaped core and exhibiting dissimilar magnetic dynamics.

The first use of the organic chelate N -hydroxy-1,8-naphthalimide (hynadH) in Dy III chemistry has unveiled access to a synthetic 'playground' composed of four new dinuclear complexes, all of which possess the same planar {Dy 2 (μ-OR) 2 } 4+ diamond-shaped core, resulting from the bridging and chelating capacity of the hynad - groups. The structural stability of the central {Dy 2 } core has allowed for the modulation of the peripheral coordination sites of the metal ions, and specifically the NO 3 - /hynad - ratio of capping groups, thus affording the compounds [Dy 2 (hynad) 2 (NO 3 ) 4 (DMF) 2 ] (1), (Me 4 N) 2 [Dy 2 (hynad) 2 (NO 3 ) 6 ] (2), [Dy 2 (hynad) 4 (NO 3 ) 2 (H 2 O) 2 ] (3), and [Dy 2 (hynad) 6 (H 2 O) 2 ] (4). Because of the chemical and structural modifications in the series 1-4, the Dy III coordination polyhedra are also dissimilar, comprising the muffin (1 and 3), tetradecahedral (2), and spherical tricapped trigonal prismatic (4) geometries. Complexes 1, 2, and 4 exhibit a ferromagnetic response at low temperatures, while 3 is antiferromagnetically coupled. All compounds exhibit out-of-phase ( χ '' M ) ac signals as a function of ac frequency and temperature, thus behaving as single-molecule magnets (SMMs), in the absence or presence of applied dc fields. Interestingly, the hynad - -rich and nitrato-free complex 4, demonstrates the largest energy barrier ( U eff = 69.62(1) K) for the magnetization reversal which is attributed to the presence of the two axial triangular faces of the spherical tricapped trigonal prism by the negatively charged O-atoms of the hynad - ligands.