Crystal structure, spectroscopy, and magnetism of alternating trinuclear, bridged hydroxo and oxo copper (II) complexes

Abstract

The synthesis, structure, and magnetic properties of a novel metal-organic framework (MOF), CFA-24 ([Cu₆(dmta)₉O(OH)]; H-dmta = 4,5-Dimethyl-1H-1,2,3-triazole), featuring alternating oxo- and hydroxo-bridged Cu (II) triangles are the focus of this study. The synthesis process of H-dmta and CFA-24 was optimized to ensure scalability and high yields, with the resulting MOF characterized using single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, and various spectroscopic techniques. Structural analysis revealed a chiral cubic crystal system (space group P2₁3), with copper ions forming equilateral triangles linked by triazoles. The study also explores the magnetic behaviour of CFA-24 using SQUID magnetometry and theoretical modeling. The magnetic data indicate strong antiferromagnetic interactions, modulated by Dzyaloshinskii-Moriya interactions (DMI), which contribute to the system's complex magnetic ground state. This research enhances the understanding of magnetically frustrated systems and positions CFA-24 as a potential candidate for spintronic applications.