Exploiting Miraculous Atmospheric CO2 Fixation in the Design of Dysprosium Single-Molecule Magnets

A system of CO32--bridged polynuclear dysprosium complexes has been complemented with the emergence of a key component, namely, (Dy-6(mu(4)-CO3)(3)(mu(3)-OH2) (spch)(6)(MeOH)(6)(H2O)(3)]center dot 4MeOH center dot 3H(2)O (3), and thus four, clysprosium(III) clusters (1-4) spontaneously fixing one, two, three, and four atmospheric CO2 molecules, respectively, have been successfully assembled. Compound 1 is a Dy-6 single-molecular magnet (SMM) (1) based on Dy-3 triangles, with one CO32- group being derived from atmospheric CO2. The incorporation of an ortho-methoxy substituent into the ligand enables access to a double-CO32- bridged Dy-6 SMM (2), where two CO32- groups occupy the two bases of the triangular prism. The trapping of three CO, molecules of the atmosphere results in the formation of compound 3, where the three CO32- groups reside on the lateral faces of a triangular prismoid. Finally, a Dy-8 SMM (4) with four CO32-, bridges on the four lateral faces of the square prismoid can be isolated-by converting four CO2 molecules. The magnetic investigations reveal that all four complexes exhibit SMM behavior with a gradual transition from the multiple to single relaxation process observed in their relaxation of the magnetization. This synthetic approach represents an efficient method to develop novel CO32--bridged lanthanide clusters through spontaneous fixation of atmospheric CO2 for magnetic dynamic studies.