Self‐Assembly Synthesis of a [2]Catenane CoII Single‐Molecule Magnet

• Published in: Angewandte Chemie International Edition Vol. 61; no. 4
• Main Authors: Wilson, Benjamin H., Ward, Jas S., Young, David C., Liu, Jun‐Liang, Mathonière, Corine, Clérac, Rodolphe, Kruger, Paul E.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 21.01.2022
• Edition: International ed. in English
• Subjects: Assembly; Catenane; Chemical synthesis; Coordination Chemistry; Magnetic induction; Magnetic moments; Magnetic properties; Magnets; Mechanically Interlocked Molecules; Metallography; Quantum tunnelling; Rectangles; Single Molecule Magnetism; Supramolecular Chemistry; Topology
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202113837

We describe herein the self‐assembly synthesis of an octanuclear CoII [2]catenane {[Co4(H2L)6]216+} formed by the mechanical interlocking of two {[Co4(H2L)6]8+} rectangles of unprecedented topology. Subtle manipulation of the synthetic conditions allows the isolation of a mixed‐valence [Co2III/Co2II]10+ non‐catenated rectangle. The CoII centers in the [2]catenane exhibit slow relaxation of their magnetic moment, i. e. single‐molecule magnet properties, dominated by quantum tunneling and Raman relaxation processes. This work shows that metallo‐supramolecular chemistry can precisely control the organization of single‐molecule magnets in topologically complex arrangements. The ligand 1,2‐bis(5‐(2‐pyridyl)‐4H‐1,2,4‐triazol‐3‐yl)benzene, H2L, self assembles with CoII to form {[Co4(H2L)6]8+} rectangles which mechanically interlock via self‐assembly to form a [2]catenane. The catenated structure displays single‐molecule magnetism (SMM), highlighting how mechanically interlocked systems can be used to arrange SMM centers in topologically complex arrays.