Water-stable Cd()/Zn() coordination polymers as recyclable luminescent sensors for detecting hippuric acid in simulated urine for indexing toluene exposure with high selectivity, sensitivity and fast response

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 5; no. 2; pp. 553 - 561
• Main Authors: Zhao, Jiao-Jiao, Zhang, Lei, Liu, Peng-Yu, Chen, Wei-Zhe, Liu, Zhi-Liang, Wang, Yan-Qin
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 14.01.2021
• Subjects: Acids; Cadmium; Cadmium - chemistry; Cadmium - urine; Coordination Complexes - chemical synthesis; Coordination Complexes - chemistry; Coordination polymers; Crystallography; Energy transfer; Fluorescence; Hippurates - chemistry; Hippurates - urine; Hippuric acid; Humans; Hydrogen bonds; Limit of Detection; Metabolites; Nitrogen atoms; Polymers - chemistry; Selectivity; Sensitivity; Sensors; Tetrazoles; Toluene; Toluene - chemistry; Urine; Water - chemistry; Zinc - chemistry; Zinc - urine
• ISSN: 1477-9226; 1477-9234; 1477-9234
• DOI: 10.1039/d0dt03648j

Three novel Cd( ii )/Zn( ii ) coordination polymers (CPs), namely [Cd(L)(BPDC) 0.5 H 2 O]·0.5H 2 O ( 1 ), [Zn 2 (L) 2 (BPDC)]·2H 2 O ( 2 ) and [Cd 2 (L)(BTC)H 2 O]·3H 2 O ( 3 ) (L = 4-(tetrazol-5-yl)phenyl-4,2′:6′,4′′-terpyridine, H 2 BPDC = 4,4′-biphenyldicarboxylic acid, and H 3 BTC = 1,3,5-benzenetricarboxylic acid), have been successfully synthesized and characterized. CP 1 and CP 2 display new two-dimensional double-layered honeycomb frameworks containing uncoordinated nitrogen atoms from pyridine and tetrazole rings, which can easily form hydrogen bonds with various analytes. CP 3 exhibits a 3D framework also with uncoordinated nitrogen atoms from pyridine and tetrazole rings. The fluorescence explorations indicate that CPs 1-3 exhibit strong blue luminescence and excellent chemical stability under a relatively wide range of pH conditions. It is worth noting that CPs 1-3 can quantitatively detect hippuric acid (HA), which is a metabolite of toluene in human urine, with high selectivity, sensitivity, fast response and relatively low detection limits. Moreover, the sensing mechanism of CPs 1-3 for HA can mainly be ascribed to fluorescence resonance energy transfer (FRET). CPs 1-3 could be ideal candidates as HA sensors in human urine samples for practical applications. Notably, to the best of our knowledge, we report for the first time Cd( ii )/Zn( ii )-based luminescent sensors for detecting HA in simulated urine. Water stable Cd( ii )/Zn( ii ) coordination polymers exhibit rapid, sensitive, selective and recyclable detection towards hippuric acid in simulated urine for indexing toluene exposure.