A First Ln−MOF as a Trifunctional Luminescent Probe for Efficient Sensing of aspartic acid, Fe3+ and DMSO
Five 3D network Ln3+ metal−organic frameworks (Ln-MOFs) formulated as [[Ln(μ6-H2cpboda)(μ2-OH2)2]·xH2O]n [Ln3+ = La3+ (1), Nd3+ (2), Sm3+ (3), Eu3+ (4), Tb3+ (5), H5cpboda =5,5'-((5-carboxy-1,3-phenylene)bis(oxy))diisophthalic acid]) have been synthesized via hydrothermal method. They have been established by single-crystal X-ray and powder diffraction analyses, elemental analysis (EA) and thermogravimetric analyses (TGAs). All compounds are isostructural with three-dimensional structures of the point symbol of (413·62)(48·66·8) in topology and crystallize in monoclinic space group P21/n. Interestingly, the solid-state luminescence of complexes 4 and 5 show intense red and green emissions, respectively. Besides, the Tb-MOF (5) is a good luminescent sensor not only to detect aspartic acid and Fe(III) ions with good stability, high efficiency and reversibility but also to exhibit rapid response and high selectivity to DMSO. To our knowledge, it is the first Ln−MOF as a luminescent probe for efficient sensing of DMSO., while the lone pair of electrons in the O of DMSO attacked the positive charge at the protonation carboxylic acid of H5cpboda. Consequently, Tb-MOF (5) is a rare and versatile fluorescent probe to aspartic acid, Fe3+ cations and DMSO simultaneously.