Lanthanide-based MOFs derived from 1,3-bis(diphenylphosphoryl)-2-oxapropane

Neutral phosphoryl podands with flexible ethylene glycol chains and diphenylphosphorylmethyl end groups are known for their complexation properties towards various cations. In this work, 2D and 3D lanthanide metal-organic frameworks (MOFs) with 1,3-bis(diphenylphosphoryl)-2-oxapropane (L) were synthesized. They were characterized by X-ray methods, IR spectroscopy and thermogravimetric analysis (TGA). The effect of the position of the metal ion Ln³⁺ in the lanthanide series on the structure of the synthesized MOFs was studied. Among the light lanthanides with ligand L, Ce³⁺ and Pr³⁺ form only 2D MOFs, while Sm³⁺, Eu³⁺, and Nd³⁺ can form both 2D and 3D MOFs in various solvent systems. Correlations between the structure of the obtained MOFs and the synthesis conditions were established. The metal ions of heavy lanthanides with a smaller radius are characterized by the formation of only 3D MOFs. The adsorption ability for CO₂ of the synthesized compounds was studied. The specific surface areas of the Tm³⁺ and Pr³⁺ MOFs were 120 m² g^-1 and 13 m² g^-1, respectively.