Phosphonate Lanthanide Carbonate Cages: Remarkably Aggregated Lanthanide-Oxo Cores with Removable Cation Templates

Phosphonate lanthanide carbonate cages represent a fascinating class of clusters capable of supplying carbonate ions to the center of the cages; furthermore, the phosphonate ligands enclose the exterior. By removing sodium templating cations and regulating the release of carbonate templating anions, two significantly aggregated lanthanide shell–core–shell topologies have now been synthesized through the reaction of lanthanide naphthalene-functionalized phosphonates and two differently terminated C2-symmetric double hydrazones. The resulting two new phosphonate dysprosium carbonate cages [Dy12Na26(μ3-O3PC11H9)(μ4-O3PC11H9)(μ6-O3PC11H9)9(μ8-CO3)7(μ9-CO3)3(L1)5(μ3-O)6(μ2-O)10(DMF)6(H2O)9]·5DMF·4MeCN·4H2O (1) and [Dy22(μ3-O3PC10H7)4(μ5-O3PC10H7)4(μ6-O3PC10H7)6(μ5-CO3)2(μ6-CO3)4(L2)4(μ2-COO)4(μ3-O)4(μ2-O)2(H2O)11]·95MeOH·78H2O (2) were obtained. Two types of hydrazones function as tridecadentate and enneadentate intercepted coligands, coordinating the periphery of phosphonate dysprosium carbonate cages. The mixed hexacosaple sodium and decaple carbonate ions act as templating cations and anions for constructing heterobimetallic 1 by filling the void, showcasing the ability to effectively control dysprosium cage aggregation in homometallic 2 through the removal of the cation and anion templates. Additionally, it was noted that the aggregation of the dysprosium shell–core–shell cages significantly influences the magnetic relaxation behavior, shifting from a field-induced two-step process in 1 to a zero-field one-step process in 2.