Cyclodextrin-Templated Co(II) Grids: Symmetry Control over Supramolecular Topology and Magnetic Properties

While inherent complexation properties and propensity for self-organization of cyclodextrins (CDs) render them potentially promising scaffolds of magnetic materials, this research area is still at an embryonic stage. We report on the synthesis and structure characterization of a new sandwich-type complex, [(alpha-CD)(2)Co3Li6(H2O)(9)] (alpha-1), which represents a smaller analogue of the previously characterized [(gamma-CD)(2)Co4Li8(H2O)(12)] (gamma-1) cluster. A comprehensive structural analysis of alpha-1 and a careful reinvestigation of gamma-1 reveal how the symmetry of CD ligands determines the molecular composition and supramolecular arrangements of Co/Li sandwich-type complexes. Furthermore, the first comparative studies of the magnetic properties in this type of system point to subtle differences in the magnetic behavior of both compounds. The sandwich-type complexes alpha-1 and gamma-1 exhibit field-induced slow magnetic relaxation, defining a new family of magnetic materials with a pillared grid-like supramolecular structure composed of weakly interacting Co-II centers forming an SMM.

Automated summary

This study reports on the synthesis and structure characterization of a new type of cyclodextrin complex with inherent self-organization. The study found that the symmetry of the cyclodextrin ligands determines the molecular composition and supramolecular arrangement of the complexes.