Post-Synthetic Functionalization of Ni-MOF by Eu3+ Ions: Luminescent Probe for Aspartic Acid and Magnetic Property.

Utilizing 5,5'-oxidiisophthalic acid (H4odip) ligand, one 3D framework {[Ni2(odip)(H2O)4(DMF)]·DMF·2H2O}n (1) with a rare 3-nodal (3,3,4)-connected topological net based on two types of Ni12(odip)12 and Ni24(odip)12 nanocages was prepared. To exploit the advantage of high porosity, 1 was employed as an MOF matrix, and then photoactive Eu3+ ions were introduced through a facile soaking method to get Eu3+ functionalized MOF composite Eu3+@1. Luminescent sensing experiment demonstrated that Eu3+@1 has the potential to serve as a sensitive, recyclable, and fast luminescent probe for aspartic acid, with a quenching constant of 1.565 × 103 L/mol. The result offers a new possibility for many MOF materials which are nonemissive and/or difficult to synthesize directly to realize luminescent sensing function similar to lanthanide MOFs. Moreover, 1 reveals a ferromagnetic character in the range of 6-35 K. The dynamic magnetization measurements displayed no frequency dependencies, suggesting the absence of slow magnetic relaxation.