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

Abstract

Neutral phosphorylpodands 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 spectra and thermogravimetric analysis (TGA). The effect of position of metal ion Ln³⁺ in the lanthanide series on the structure of synthesized MOFs were studied. Among the light lanthanides with ligand L, Ce³⁺ and Pr³⁺ form only 2D MOFs, while Sm³⁺, Eu³⁺, 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 made. The metal ions of heavy lanthanides with a smaller radius are characterized by the formation of only 3D MOFs. The adsorption ability of CO₂ by synthesized compound was studied. The specific surface area of Tm³⁺ and Pr³⁺ MOFs is 120 m²/g and 13 m²/g respectively.