Pentacosaple-CO32− bridged hexacontaoctanuclear lanthanide-alkali barrels derived from octacosanuclear discs

Abstract

Phosphonate lanthanide carbonate cages are highly sought after in the development of multifunctional molecular-based materials due to their rigid framework and the inherent properties of metal ions. However, the synergistic coordination of phosphonates and carbonates with lanthanide ions limits their systematic exploration. Here, we developed an efficient method to synthesize the necessary phosphonate lanthanide carbonate compound with a three-shell topology through a stepwise procedure that employs a strategy involving the assembly of several multicomponent systems, aimed at the distinctive C₂-symmetric double hydrazone-based co-ligands. The resulting octacosanuclear disc [Dy₁₆K₁₂(μ₄-O₃PC₁₀H₇)₂ (μ₅-O₃PC₁₀H₇)₁₂(μ₆-O₃PC₁₀H₇)₂(L¹)₄(μ₄-COO)₄(μ₂-COO)₂(μ₃-O)₄(DMF)₆(MeOH)₂(H₂O)₄]·8DMF·4MeCN·8H₂O (Dy₁₆K₁₂) and hexacontaoctanuclear barrel [Dy₂₄Na₄₄(μ₄-O₃PC₁₁H₉)₈(μ₇-O₃PC₁₁H₉)₈(μ₇-CO₃)₁₂(μ₈-CO₃)₁₃(L²)₈(μ₆-Cl)₂(μ₂-OH)₈(DMF)₈(H₂O)₈]·2DMF·6MeOH·9H₂O (Dy₂₄Na₄₄) were achieved by leveraging the benefits of incorporating mixed chloride and carbonate templating anions along with the replacement of alkali metal ions. In the molecular structure of compound Dy₂₄Na₄₄, twenty-five carbonate and two chloride anions not only occupy the central cavity of the barrel-shaped framework but also act as crucial bridging units in assembling the molecular topology. Furthermore, the drastic changes in supramolecular structures directly affect magnetic dynamics phenomena, from the field-induced complex relaxation phenomenon to the zero-field single relaxation phenomenon. This work represents an efficient approach for synthesizing phosphonate lanthanide carbonate cages, thereby broadening the pathway for the ultimate customization of functions.