Synthesis of Fluoro-Bridged Ho³⁺ and Gd³⁺ 1,3,5-Tris(4-carboxyphenyl)benzene Metal–Organic Frameworks from Perfluoroalkyl Substances

Abstract

A new fluoro-bridged rare-earth (RE) metal–organic framework consisting of 15-connected nonanuclear and 9-connected trinuclear clusters {[RE 9 -(μ 3 -F) 14 (H 2 O) 6 ][RE 3 (μ 3 -F)(H 2 O) 3 ](HCO 2 ) 3 -(BTB) 6 }·(solvent)x 2 (RE = Ho 3+ and Gd 3+ ) was synthesized through the transformation of a dimeric complex formulated as bis(2,2′-bipyridine)tetrakis(μ-2-fluorobenzoato- O, O ′)-bis(2-fluorobenzoato)diRE(III) 1 with the bridging linker 1,3,5-tris(4-carboxyphenyl)benzene (H 3 BTB). The rare-earth metal ions Ho 3+ and Gd 3+ were also found to remove fluorine from other organo-fluorine compounds such as perfluorohexanoic acid (PFHxA) and perfluorooctanoic acid (PFOA), resulting in the new fluoro-bridged RE-MOFs.