Design and Self-Assembly of Ferrocene-Functional Heterometal-Oxo Clusters with the M(III)₄O₄ Cubane Core

In this work, we synthesized two Cu-based heterometal-oxo clusters 1 and 2 based on M(III)(4)O-4 (M = Fe/In) cubane centers and obtained the corresponding dimers 3 and 4 by connecting Cu atoms on the cluster cores with the auxiliary ligand 4,4 '- bipyridine. They were characterized by single-crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), and other tests. We conducted magnetic property study on compounds 1-4. The variable-temperature magnetic susceptibility test shows that compounds 1 and 3 exhibit significant ferromagnetic interactions at low temperatures, while compounds 2 and 4 exhibit overall antiferromagnetic interactions. When the metal at the cubane changes from magnetic Fe to nonmagnetic In, the magnetic interactions in the compound are weakened to a certain extent. Through dimerization, the extreme values of the variable-temperature magnetic susceptibility appear (1 to 3)/disappear (2 to 4) in the low-temperature section. We investigated the magnetic structure correlation of compounds 1-4 through bond lengths, bond angles, and distances between magnetic atoms. The results showed that compounds 1-4 exhibited significant magnetic coupling diversity.