Selective detection of paraquat by a cucurbit[7]uril-based fluorescent probe.

A simple fluorescent "on-off" system that can be utilized for the selective identification and determination of paraquat (PQ) is presented herein. H NMR spectroscopic data indicated that in aqueous solution the alkaloid palmatine can be partially encapsulated within the cucurbit[7]uril (Q[7]) cavity, whereby a stable 1 : 1 host-guest inclusion complex is formed. Other characterization techniques including mass spectrometry, UV-Vis and fluorescence spectroscopy also provided further evidence, and the host-guest inclusion complex was found to exhibit reasonable fluorescence intensity.

Supramolecular Assembly of Tetramethylcucurbit[6]uril and 2-Picolylamine.

The supramolecular assembly of symmetrical tetramethylcucurbit[6]uril (TMeQ[6]) and 2-picolylamine (AMPy) has been investigated via various techniques, including ultraviolet-visible (UV-vis) and nuclear magnetic resonance spectroscopy, isothermal titration calorimetry (ITC), and X-ray crystallography. The results indicated that TMeQ[6] could encapsulate the AMPy guest molecule to form a stable inclusion complex. The rotational restriction of the guest in the cavity of TMeQ[6] resulted in a large negative value of entropy.

Facile fluorescent detection of o-nitrophenol by a cucurbit[8]uril-based supramolecular assembly in aqueous media.

The efficient and selective detection of isomers is an attractive but challenging area. In this study, a supramolecular fluorescent probe based on cucurbit[8]uril (Q[8]) and a pyrene-based derivative (G) was prepared, which effectively recognized and removed o-nitrophenol (o-NP) from a mixture of nitrophenol isomers. The newly designed probe G@Q[8] was characterized by NMR spectroscopy, fluorescence emission and UV-Vis spectroscopy, and its host-guest properties in aqueous solution were investigated.

Cucurbit[10]uril-mediated Supramolecular Assembly for Optically Tunable Dimers and Near White-light Emissive Materials.

Cucurbit[10]uril (Q[10]), the cucurbit[n]uril with a large cavity, exhibits several new features in the development of the host-guest complex. Thus, based on Q[10] and π-conjugated molecule, oligo(p-phenylenevinylene) derivative (OPVCOOH), the host-guest complexes with three different interaction ratios of 1 : 2, 2 : 2, and 3 : 2 assemblies (Q[10]: guest) were fabricated. Depending on the host/guest ratio, the emission color of these complexes ranged from blue to yellow-green.

Pyridine Detection Using Supramolecular Organic Frameworks Incorporating Cucurbit[10]uril.

A physical impregnation method is presented in this study, providing a facile approach to encapsulating functional guest molecules (GMs) into robust crystalline supramolecular organic frameworks incorporating cucurbit[10]uril (Q[10]-SOF). As Q[10]-SOF has high evaporated pyridine affinity under normal atmospheric pressure, pyridine molecules in this method were successfully encapsulated into the nanospace formed by GMs and Q[10]-SOF while retaining their crystal framework, morphology, and high stability. GMs@Q[10]-SOF solid materials were found to respond to pyridine, being suitable to be used as solid sensors.

A fluorescent probe based on cucurbit[7]uril for the selective recognition of phenylalanine.

Herein we describe a simple fluorescence quenching method for the selective recognition and determination of the amino acid phenylalanine (Phe). The use of H NMR spectroscopy revealed that the alkaloid palmatine (PAL) can encapsulated partially into the cavity of cucurbit[7]uril (Q[7]) in aqueous solution to form a stable 1:1 host-guest inclusion complex. This host-guest complex exhibits fluorescence of moderate intensity.

Selective recognition and determination of phenylalanine by a fluorescent probe based on cucurbit[8]uril and palmatine.

This paper demonstrated a simple and validated fluorescence enhancing method to selectively recognize and discriminate the amino acid phenylalanine (Phe). H NMR spectroscopy reveal that the palmatine (PAL) can be encapsulated into the cucurbit [8]uril (Q [8]) in aqueous solution to form stable 1:2 host-guest inclusion complex PAL@Q [8], which exhibits moderate intensity fluorescence property. Interestingly, the addition of the Phe into the inclusion complex PAL@Q [8] leads to dramatically enhancing of the fluorescence intensity.