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

A new fluoro-bridged rare-earth (RE) metal-organic framework consisting of 15-connected nonanuclear and 9-connected trinuclear clusters {[RE9- (mu 3-F)14(H2O)6][RE3(mu 3-F)(H2O)3](HCO2)3-(BTB)6}center dot(solvent)x 2 (RE = Ho3+ and Gd3+) was synthesized through the transformation of a dimeric complex formulated as bis(2,2 '-bipyridine)tetrakis (mu-2-fluorobenzoato-O,O ')-b is (2fluorobenzoato)diRE(III) 1 with the bridging linker 1,3,5-tris(4-carboxyphenyl)benzene (H3BTB). The rare-earth metal ions Ho3+ and Gd3+ were also found to remove fluorine from other organo-fluorine compounds such as perfluorohexanoic acid (PFHxA) and perfluorooctanoic acid (PFOA), resulting in the new fluorobridged RE-MOFs.