CrystEngComm

Abstract

Uric acid (UA) is a vital indicators for various metabolic diseases, tryptophan (Trp) is one of the eight essential amino acids in the human body. UA and Trp both play important role for human health. Here, a fluorescent Zn(II) metal–organic framework (MOF), {[Zn2(bptc)(1,2-mbix)2]2∙EtOH}n (1) (H4bptc = 3,3’,4,4’-biphenyltetracarboxylic acid, 1,2-mbix = 1,2-bis(2-methyl-imidazol-1-ylmethyl)benzene), has been obtained and explored for sensing of UA and Trp. MOF 1 represents a 3D framework with an interesting two-fold interpenetrated bbf topology. MOF 1 exhibits excellent fluorescence performance for turn-off sensing of UA and turn-on sensing of Trp in water. The limits of detections (LODs) for UA and Trp are 1.26 and 0.30 μM, respectively. The experimental results and theoretical calculations indicate that the turn-off sensing of UA should be attributed to the competitive absorption between 1 and UA, and the turn-on sensing of Trp should be due to the photoinduced electron transfer (PET) from Trp to the ligands of 1. Moreover, the practicality of 1 was verified by detecting UA in serum and Trp in milk.