Five Mesoporous Lanthanide Metal-Organic Frameworks: Syntheses, Structures, and Fluorescence Sensing of Fe 3+ , Cr 2 O 7 2- , and H 2 O 2 and Electrochemical Sensing of Trinitrophenol.

When a multicarboxylate aromatic ligand, 3,5-di(2',4'-dicarboxylphenyl)benzoic acid (H 5 L), was employed, five structurally similar lanthanide metal-organic frameworks (Ln-MOFs), {[Pr 10 L 6 (OH) 3 Cl(H 2 O) 6 ]·4C 2 H 8 N} n ( 1 ), {[Nd 10 L 6 (OH) 4 (H 2 O) 9 ]·4C 2 H 8 N} n ( 2 ), {[Gd 10 L 6 (OH) 4 (H 2 O) 3 ]·4C 2 H 8 N} n ( 3 ), {[Ho 10 L 6 (OH) 4 (H 2 O) 3 ]·4C 2 H 8 N} n ( 4 ) and {[Er 10 L 6 (OH) 4 (H 2 O) 6 ]·4C 2 H 8 N} n ( 5 ), were synthesized and characterized. Single-crystal X-ray structural analyses disclosed that all five Ln-MOFs crystallize in the trigonal R 3 space group. They have three-dimensional mesoporous structure featuring the coexistence of binuclear and tetranuclear species as inorganic building units. The mesoporous structure of 3 was verified by the gas adsorption experiment of N 2 . Fluorescence analysis showed that 3 can selectively detect Fe 3+ , Cr 2 O 7 2- , and H 2 O 2 ; furthermore, it can be used for the electrochemical detection of trinitrophenol. With the merit of an excellent highly sensitive detection performance, 3 has unpredictable application prospects in future research fields.