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A comprehensive photophysical and NMR investigation on the interaction of a 4-methylumbelliferone derivative and cucurbit[7]uril
摘要： The host-guest interaction of a 7-hydroxycoumarin (3-[2-(diethylamino)ethyl]-7-hydroxy-4-methylcoumarin, 3ED4MU) with cucurbit[7]uril, CB7, was investigated in aqueous solution. From the steady-state fluorescence Job plot and 1H NMR spectroscopy the formation of a 1:1 inclusion complex, with a binding constant of 1.75×105 M?1 was obtained. Time-resolved fluorescence data in water, DMSO and dioxane for 3ED4MU and for umbelliferone (UM, here taken has the model compound) show that the decays are double or triple-exponentials mirroring the presence of excited neutral (N*), anionic (A*), tautomeric (T*) and zwiterionic (T*’) species (the latter only present in 3ED4MU). In the time-resolved experiments, the interaction of 3ED4MU with CB7 is mirrored by an increase of the pre-exponential factor associated to the zwiterionic species (thus giving support for the stabilization of this species when interacting with CB7) and a dramatic change in the pKa* value (from ~ 0.5 to ~8), associated to a displacement of the water environment probed by 3ED4MU.
关键词： Time-resolved fluorescence,Host-guest chemistry.,Binding constant,Fluorescence,Hydroxycoumarins,Cucurbit[7]uril
更新于2025-09-23 15:23:52
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Anthracene-based cyclophanes with selective fluorescent responses for TTP and GTP: insights into recognition and sensing mechanisms
摘要： Three anthracene-based cyclophanes have been synthesized and their binding properties towards nucleoside triphosphates have been studied. A new polycyclic amine derived from dearomatized anthracene has been identified as a major side product in the reaction between 9,10-anthracenedicarboxaldehyde and diethylenetriamine. Its structure has been determined by the single crystal X-Ray analysis. The cyclophanes have been found to form 1:1 complexes with all nucleoside triphosphates as well as with pyrophosphate in a buffered aqueous solution at pH 6.2. A turn-on fluorescence response has been observed for all nucleotides except for GTP, which demonstrated strong fluorescence quenching. The strongest turn-on fluorescence answer has been observed for the largest receptor 3 in the presence of TTP. Based on the NMR and fluorescence experiments two major binding modes for nucleotide complexes have been identified.
关键词： macrocycle,host-guest chemistry,nucleotide recognition,synthetic receptor,fluorescence sensing
更新于2025-09-23 15:22:29
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Fluorescent Calixarene Scaffolds for NO Detection in Protic Media
摘要： Here, we present the first fluorescent water-soluble conjugated calixarene scaffolds that are capable of detection of NO gas. Two different scaffolds, one based on a 5,5’-Bicalixarene structure and its isomer bearing two distantly conjugated calixarene moieties, have been synthesized. While the fluorescence of both isomers is quenched upon either passing of NO gas or generating it in-situ from diethylamine NONOate, the bicalixarene-based scaffold showed a significantly stronger response. We also present an example of a dye encapsulation strategy to achieve the detection of NO at longer wavelengths than in the parent calixarene host. Finally, a conjugated polymer bearing 5,5’-Bicalixarene scaffold has also been prepared and demonstrated enhanced sensitivity compared with the monomer due to the molecular wire effect.
关键词： conjugated systems,nitric oxide,host-guest chemistry,fluorescent probes,Calixarene
更新于2025-09-23 15:22:29
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Photoresponsive Structured Liquids Enabled by Molecular Recognition at Liquida??Liquid Interfaces
摘要： Using the host-guest molecular recognition at the oil-water interface, a new-type photo-responsive nanoparticle surfactant (NPS), is designed and prepared to structure liquids. With the help of a polymeric surfactant, the interfacial host-guest interactions can be significantly enhanced, leading to a rapid formation and assembly of a NP monolayer, and offering sufficient binding energy to hold the NPs in a jammed state. The assembly of the NPSs can be reversibly manipulated via a photo-switchable jamming to unjamming transition, endowing the interface, as well as the macroscopic assemblies, with responsiveness to the external trigger (photons). This study, for the first time, opens the pathway for the construction of multi-responsive, structured all-liquid systems by introducing host?guest chemistry, showing promising potential applications in encapsulation, delivery systems, and unique microfluidic devices.
关键词： self-assembly,liquid-liquid interfaces,host-guest chemistry,Structured liquid,nanoparticle surfactants
更新于2025-09-23 15:19:57
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Fabrication of a Tyrosine Responsive Liquid Quantum dots based Biosensor Through Host-Guest Chemistry
摘要： Design and fabrication of a smart liquid quantum dots (LQDs) with high biomolecules selectivity and specificity remains a challenge. Herein, a multifunctional calix[4]arene derivatives (PCAD) was rationally designed and applied to fabricate a Tyr-responsive CdSe-LQDs system through host-guest chemistry. Such this biosensor displays an outstanding fluorescence/macroscopic response for Tyr and reversible fluidic features due to the hydrogen interaction between the PCAD of CdSe-LQDs and Tyr. These excellent results highlighted CdSe-LQDs as a promising platform for biological molecules recognition and separation in the future.
关键词： Calix[4]arene,Liquid Quantum dots,Biosensor,Host-Guest Chemistry,Tyrosine detection
更新于2025-09-11 14:15:04
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Molecular recognition and fluorescent sensing of urethane in water
摘要： Molecular recognition and fluorescent sensing of Group 2A carcinogen -- urethane was achieved in aqueous solution. The molecular sensors are the endo-functionalized molecular tubes with amide protons in the hydrophobic cavity. 1H NMR, fluorescence, and ITC titrations and single crystal X-ray crystallography reveal the binding stoichiometry, the binding affinities, and the driving forces. The binding is mainly driven by the hydrophobic effect through releasing the “high-energy” cavity water with minor contribution from hydrogen bonding. In addition, the syn-configured molecular tube was found to be a good fluorescent sensor for urethane in water (concentration range: 6.2 μmol/L - 60 μmol/L) and in beer (concentration range: 22.9 μmol/L – 60 μmol/L).
关键词： Molecular recognition,Urethane,Host-guest Chemistry,Fluorescent sensing
更新于2025-09-10 09:29:36