Formation of a Magnetically Coupled Neutral [4 x 4] Square Grid from a 2,6-Pyridinedicarbaldehyde Bis(hydrazone) Ligand

The synthesis, characterization, magnetic properties, and magnetostructural correlation of a square-grid complex having the molecular formula [Cu16L81](dmf)(3) (1) {H4L1 = 2,6-bis[(3-methoxysalicylidene)hydrazinecarbonyl]pyridine} is described. Reaction of the H4L1 ligand and the Cu2+ salt generates complex 1, which exhibits a rare grid structure with a [4x4] metallic core of Cu2+. Structural studies revealed a mixed coordination geometry around the Cu2+ core. The molecule has a fourfold rotational axis and one inversion center. Magnetic investigations showed the coexistence of both ferro- and antiferromagnetic spin exchanges, though antiferromagnetic exchange dominates over ferromagnetic coupling in the low-temperature region.