A uranyl-based metal–organic framework featuring an eight-connected U4L2 cage for guest capture

Abstract

A novel (3,6)-connected uranyl-based MOF (IHEP-50) was synthesized by a judicious combination of UO₂²⁺ and polycarboxylic acid, 4,4′,4′′,4′′′,4′′′′,4′′′′′-(((1,3,5-triazine-2,4,6-triyl)tris(azanetriyl))hexakis(methylene))hexabenzoic acid (H₆DTPCA). Two DTPCA⁶⁻ ligands are connected together via four uranyl cations to form a lantern-shaped cage U₄L₂, which is further connected with other eight equivalent ones to form a 3D porous framework with two kinds of 1D channels. These large pore structures give it certain potential for guest molecule capture. Adsorption experiments indicate that IHEP-50 can selectively remove positively charged dyes over negatively charged and neutral ones. In addition, IHEP-50 demonstrates notable adsorption performance for gaseous iodine, achieving a maximum adsorption capacity of 253.5 mg g⁻¹.