Zunsheng Cai

A phenylhydrazone-based indole receptor for sensing acetate

A novel phenylhydrazone-based indole anion receptor is synthesized by a simple method, and the receptor binds acetate anions with good selectivity in DMSO solution, which is related to the structure of the receptor matching with the anion. The binding properties of the host are examined by UV-vis changes. The color changes of the host upon the addition of a variety of structurally different anions were also utilized as nake-eyed recognization (from orange to purple, first figure), The hydrogen bonds between recognization sites (phenylhydrazone and indole N-H) and anions were determined on the basis of (1)H NMR experiments.

A novel anthracene-based receptor: Highly sensitive fluorescent and colorimetric receptor for fluoride

A new highly sensitive colorimetric receptor 1 for fluoride based on anthracene-9,10-dicarbaldehyde bis-p-nitrophenylhydrazone was designed, synthesized and characterized. Experiments showed that the receptor 1 can selectively recognize the fluoride in DMSO and even in 95/5 DMSO/H(2)O (v/v) mixtures. The ability of recognition and the bond between receptor 1 and anions were determined using visual inspection, UV-vis and fluorescence analyses. In addition, (1)H NMR experiments were carried out to explore the nature of interaction between receptor 1 and fluoride. Finally, analytical application and detection of fluoride in toothpaste have been studied.

Effects of the receptors bearing phenol group and copper(II) on the anion recognition and their analytical application

Two novel artificial receptors based on diamide and bearing phenol group and copper(II) have been synthesized. Their anion-binding properties are evaluated for F(-), Cl(-), Br(-), I(-), AcO(-), H(2)PO(4)(-) and OH(-) by UV-vis and (1)H NMR titration experiments to further elucidate the impact of phenol group and copper(II) on the chemistry of anion-recognition. Results indicate that the interacted model of fluoride anion with receptor 1 is different from other anions and the (1)H NMR signals of receptor 2 occur changes after the addition of fluoride anion. This may be related with the small radius and strong electronegative property of fluoride. The receptors should have many chemical and analytical applications and the sensing principle should be widely applicable to the sensing of other receptors.

A simple colorimetric and ON-OFF fluorescent chemosensor for biologically important anions based on amide moieties.

A simple colorimetric and fluorescent anion chemosensor based on amide moieties, 6-nitro-1,4-dihydroquinoxaline-2,3-dione has been designed, synthesized and characterized by (1)H NMR, ESI-MS and elemental analyses. The strong basic anions such as F(-) and AcO(-) resulted in significant decrease in fluorescent emission intensity of the compound 1, accompanied synchronously with a dramatic color change from colorless to deep yellow in organic medium. (1)H NMR titration experiments shed light on the nature of the interactions between 1 and the anions.

A Simple and Neutral Receptor Acting as a Sensitive and Switch-on Fluorescent Chemosensor for H2PO4−

AbstractsA novel artificial anion chemosensor 1 based on 2, 2′-di (4-nitrophenylurea-β-N-yl) -1, 1′-binaphthyl is designed and synthesized for sensing anions including halide ions and oxoanions. The fluorescent emission of the binaphthyl of receptor 1, forming the hydrogen bonding with anions as the sensing mechanism, is monitored in DMSO for detecting anions. In brief, while most of the anion chemosensors are switch-off fluorescent chemosensor, or non-fluorescent sensor, receptor 1 exhibits obviously the switch-on emission during the complexation with H2PO4−.

Design of Two Pyrazole-Based Sensors with Similar Configuration and Different Fluorescent Response to Anions

Two simple fluorescent anion receptors based on 1-phenyl-3-methylpyrozole-5-one-4-one phenylhydrazone (L1) and 1-phenyl-3-methylpyrozole-5-one-4-one p-nitrophenylhydrazone (L2) were designed, synthesized and characterized with 1H NMR, COSY spectrum, 13C NMR, ESI-mass and elemental analyse. Interestingly, two receptors with similar configuration exhibited different anion binding behaviors in DMSO solution. The results of Job plots and ESI-mass spectrum indicate that L1 bind anions such as F−, AcO−, H2PO4− to form 2:1 host-guest complexation, while L2 bind anions to form 1:1 host-guest complexation in the solution.

Colorimetric and fluorogenic anion sensors of 2′-(p-nitrophenyl)-imidazol[4′,5′-f]-1,10-phenanthroline[5,6-f] and its complex of

2′-(p-nitrophenyl)-imidazol[4′,5′-f]-1,10-phenanthroline[5,6-f] (1) and its complex (2) were synthesised and studied for the anion sensing by UV–vis, fluorescence and 1H NMR titration experiments. Compounds 1 and 2 exhibited obviously different changes between reactions with AcO− , F− , and with other halogens, i.e. Cl− , Br− , I− , in any of the UV–vis, fluorescence and 1H NMR titration spectra in DMSO experiments. With an 89 nm red shift, 1 was convenient to be employed to detect anions with the naked eye. Complexed with the electron withdrawing metal ion, 2 had the stronger interaction with anions to be detected than 1 had.