Amino acid and acetone fluorescence sensors based on a stable light-emitting Cd(II) metal-organic framework with derivatives of isonicotinic acid

As one of the most promising category of functional materials, luminescent metal–organic frameworks (LMOFs) have been widely investigated as fluorescence chemical sensors which can offer a reliable diagnostic tools in biomedical research. Herein, a luminescent Cd-MOF [Cd2(L)2(H2O)]n (Cd-MOF) (H2L = 3-(3-carboxylphenyl) isonicotinic acid), was synthesized by and characterized in detail. Single-crystal structure determination reveals that Cd-MOF crystalizes in the monoclinic crystal system with C2/c space group. Experimental results show that Cd-MOF is a highly selective and sensitive luminescent sensor for rapidly detecting acetone, L-Tryptophane (L-Trp) and L- Aspartic acid (L-Asp) in water. It can significantly test acetone in common solvents, selectively identify L-Trp and L-Asp in 12 amino acid aqueous solutions, and enhance the fluorescence signal of Tryptophan and quench L-Asp with the detection limit of 17.6 μM and 68.8 μM respectively. However, upon the interaction with electron rich amino acid (L-Trp), the Cd-MOF shows the selective “Turn-On” behaviour, which may also be supported by the DFT studies.