Synthesis, characterization, magnetism and theoretical analysis of hetero-metallic [Ni2Ln2] partial di-cubane assemblies.

A family of four isostructural [Ln2Ni2(L)2(μ3-OCH3)2(μ1,3-PhCO2)2(PhCO2)2(CH3OH)4]·2CH3OH [where Ln = Gd (1), Tb (2), Dy (3) and Ho (4)] complexes has been synthesized using Schiff base ligand 2-[{(2-hydroxybenzyl)imino}methyl]-6-methoxyphenol (H2L). All the complexes possess a partial di-cubane core structure where the growth of the core is contingent upon the ligand anions and solvent generated μ3-OCH3 groups. DC magnetic analysis revealed dominating ferromagnetic interactions between the metal ions, however, we find no slow relaxation characteristics in the AC susceptibility. Further insight into the magnetic behavior of the reported complexes was achieved using DFT and CASSCF theoretical calculations, leading to the comprehension of the fast relaxation characteristics observed by magnetometry.