Syntheses, Structures, and Magnetic Properties of Novel [3×1 + 2×1] Pentanuclear Zinc(II)-Lanthanide(III) Cocrystal Complexes: Slow Magnetic Relaxation Behavior of the Dy(III) Analogue
Authors :- Roy S., Du J., Manohar E.M., Aziz T., Pal T.K., Sun L., Ahmed N., Das S.
Publication :- Crystal Growth and Design, 2023, 23, 4, 2218–2230.
A new family of 3d-4f polynuclear cocrystals [LnZn2L2(CH3CO2)4]·[Zn2Cl4L]·H2O [where LnIII = Gd(1), Tb(2), and Dy(3)] are synthesized by the sequential reaction of a tetradentate multisite coordinating compartmental ligand, i.e., (E)-2-methoxy-6-(((pyridine-2-ylmethyl)imino)methyl)phenol, in the presence of LnCl3·6H2O and Zn(OAc)2·2H2O. The detailed studies involve mainly synthesis, structure, and magnetic properties of three isostructural cocrystals. The X-ray diffraction analysis reveals that complexes 1–3 crystallize in triclinic crystal system with the P1̅ space group. The dimeric [Zn2Cl4L]− complex appears as a cocrystal in the vicinity of the [LnZn2L2(CH3CO2)4]+ crystal structure to counter balance the overall charge on the primary coordination sphere. Magnetic relaxation studies indicate that zero-field out-of-phase magnetic susceptibility signals are observed only for complex 3 (DyIII analogue) which gets well resolved in the presence of a Hdc = 0.5 kOe magnetic field. The extracted effective energy barrier (Ueff) and pre-exponential factor (τ0) for 3 is found to be 13.53 K and 1.78 × 10–6 s, respectively. The appearance of single-ion magnet properties for 3 is rationalized with CASSCF/SO-RASSI/SINGLE_ANISO based ab initio calculations.