Tuning Crystal Packing and Magnetic Properties in a Series of [Dy 12 ] Metallocubanes Based on Azobenzene Derivatives of Salicylic Acid.

A series of four new Dy 12 dodecanuclear clusters based on azobenzene derivative ligands of salicylic acid ( L1 - L4 ) has been synthesized and characterized in the crystalline phase using X-ray diffraction on single crystal and powder, IR spectroscopy, elemental analysis, and DSC-TGA methods. It was revealed that all obtained clusters exhibit the formation of the similar metallic cluster nodes, as vertex-sharing heterocubanes, obtained from four Dy 3+ cations, three bridging hydroxyl groups, and O atoms from the salicylic ligands. The coordination geometry around the Dy(III) centers has been carefully analyzed. Whereas Dy 12 -L1 and Dy 12 -L2 with L1 and L2 containing Me and OMe groups in para positions of the phenyl rings, respectively, form similar porous 3D diamond-like molecular networks due to CH-π interactions, for Dy 12 -L3 with L3 bearing NO 2 -electron-withdrawing group, the generation of 2D molecular grids assembled by π-π staking is observed, and for Dy 12 -L4 with L4 bearing phenyl substituent, 3D hexagonal channels have been generated. The complexes Dy 12 -L1 , Dy 12 -L2 , and Dy 12 -L3 exhibit a zero-field slow magnetic relaxation effect. After UV irradiation of Dy 12 -L1 , a decrease of the magnetic anisotropy energy barrier displaying the possibility of control over magnetic properties by the external stimulus has been observed.