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A novel selective and sensitive colorimetric receptor 1 (1, 10-phenanthroline-2, 9-dialdehyde bis-(-p-nitrophenylureasemicarbo-hydrazone)) based on urea showing distinctive color fading phenomenon towards H2PO4− ion was reported. Fancifully, the recognition process of receptor 1 to H2PO4− was not interfered by the existence of others anions. We have probed the binding mechanism of 1-H2PO4− that H2PO4− ion induced competitive hydrogen binding process via intramolecular hydrogen-bond by UV-vis, fluorescence, 1H NMR titrations and ESI-MS experiments. [ABSTRACT FROM AUTHOR]

A novel selective and sensitive colorimetric receptor 1 (1, 10-phenanthroline-2, 9-dialdehyde bis-(-p-nitrophenylureasemicarbo-hydrazone)) based on urea showing distinctive color fading phenomenon towards H2PO4− ion was reported. Fancifully, the recognition process of receptor 1 to H2PO4− was not interfered by the existence of others anions. We have probed the binding mechanism of 1-H2PO4− that H2PO4− ion induced competitive hydrogen binding process via intramolecular hydrogen-bond by UV-vis, fluorescence, 1H NMR titrations and ESI-MS experiments. [ABSTRACT FROM AUTHOR]

A simple, novel anion receptor based on 4-hydroxy-3-(N-phenyl-thiourea-N′-nitrilo-methylidynyl)-azobenzene with hybrid –OH and thiourea binding sites was synthesized and characterized. Anion binding character was determined using visual inspection, UV–vis, fluorescence and 1H NMR analyses. The addition of F−, AcO− and H2PO4 − resulted in a marked red shift of the charge-transfer absorbance band (Δλ =140nm, from 340nm to 480nm) accompanied by a color change from light yellow to orange. [Copyright &y& Elsevier]

Abstract: A simple colorimetric and ratiometric fluorescent anion sensor 1, 3,6-dichloro-1,8-dinitrocarbazole, was rationally designed and synthesized on basis of the mechanism of intramolecular charge transfer (ICT). In DMSO solutions of 1, the presence of AcO−, F− and H2PO4 − gave birth to the formation of a 2:1 host-to-guest complex, which was synchronously accompanied by a ‘naked-eye’ color change from light yellow to purple, a red-shift of the absorption spectrum and a blue-shift of the emission spectrum. [Copyright &y& Elsevier]

Abstract: Two novel highly sensitive colorimetric acetate anion receptors: 4-phenylazo-2-hydroxy-benzaldehyde 4-nitrophenylhydrazone (1) and 4-phenylazo-2-hydroxy-benzaldehyde 2,4-dinitrophenylhydrazone (2) based on azo derivative have been designed and synthesized. UV–vis experiments show that receptor 1 and receptor 2 can selectively recognize acetate in DMSO and even in 9/1 DMSO/H2O (v/v) mixtures. Meanwhile the color changes induced by anions can provide a way of detection by ‘naked-eye’. The further insights to the nature of interactions between receptor 1, 2 and AcO− have been investigated by 1H NMR titration experiments. [Copyright &y& Elsevier]

Abstract: A novel artificial anion receptor based on phenylhydrazone structure was designed, synthesized and characterized. The binding behavior of the receptor to various anions was investigated by UV–vis fluorescence analyses. In addition, 1H NMR experiments were carried out to explore the nature of interaction between receptor 1 and acetate. The processes of sensing can literally be seen through the ‘naked-eye’ for the sharp color changes from yellow to purple. [Copyright &y& Elsevier]

Abstract: A colorimetric sensor 1,N,N′-di-(2-hydroxy-5-(phenldiazenyl)benzaldehyde)-1,3-diiminothiourea for acetate in DMSO and 9/1 DMSO/H2O (v/v) mixtures was designed and synthesized. The binding ability evaluated by UV–vis experiment reveals that sensor 1 can selectively recognize acetate. In addition, the color changes induced by anions can provide a way of detection by ‘naked-eye’. The further insights to the nature of interactions between the sensor 1 and AcO− were investigated by 1H NMR titration experiments in 9/1 DMSO-d 6 /H2O (v/v). [Copyright &y& Elsevier]

Abstract: 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/H2O (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, 1H 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. [Copyright &y& Elsevier]

Abstract: A novel and efficient receptor based on the phenylhydrazone derivatives is successfully developed and applied to the acetate anion recognition, indicating that the origin of special preference for acetate (AcO−) anion maybe the structure well matching between the host and the guest. The sensor changes its color so obviously on addition of the acetate ions and that may make the naked-eye recognition in DMSO and even in DMSO/H2O (95/5) solution come true. Also, the anion binding ability determinations were performed by UV–vis titration and 1H NMR titration experiments with different anions in the solutions mentioned. The fluorescence enhancement can also be observed after the host is coordinated with the AcO− anion and excited by light wavelength at 280nm. [Copyright &y& Elsevier]

Abstract: A sensitive colorimetric sensor (1) based on 4,5-dinitrobenzene-1,2-diamine was designed and synthesized. Binding of anions such as AcO−, F− and results in a notable change in the visible region of spectrum (an approximately 90nm red shift), which can be detected by the ‘naked-eye’. Furthermore, the binding ability was evaluated by UV–vis titration experiments as following: AcO− >F− > ≫Cl−, Br−, I−. The nature of the color change of 1 induced by AcO− was due to the intramolecular charge transfer (ICT) which was confirmed by X-ray crystal structure and 1H NMR titration spectra. [Copyright &y& Elsevier]

Abstract: A new and simple salicylaldehyde-based sensor 1 designed for fluoride sensing has been investigated in DMSO and even in the 9/1 DMSO/H2O (v/v) mixtures. The affinity constants of receptor 1 for anionic species in the 9/1 DMSO/H2O (v/v) reveal that it is sensitive to F. Also, the color changes induced by anions can provide a way of detection by ‘naked-eye’. These result can be substantiated by the spectrum changes upon the addition of 25equiv. anions to 1 in the 9/1 DMSO/H2O solution. The further insights to the nature of interactions between the sensor 1 and F− were investigated by 1H NMR titration experiments in 9/1 DMSO-d 6/H2O (v/v). In addition, the proposed binding mode between 1 and F− was suggested. [Copyright &y& Elsevier]

Abstract: 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 1H 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. 1H NMR titration experiments shed light on the nature of the interactions between 1 and the anions. [Copyright &y& Elsevier]

Abstract: Tris–hydrazone (1) functioned as a colorimetric chemosensor for a variety of anions such as F−, AcO− and H2PO4 −. The anion binding could be easily detected by naked-eye according to color changes. The high binding ability of the receptor 1 to anions was further investigated by UV–vis absorption spectroscopy in DMSO. The results of job plot of the receptor 1 with different anions demonstrated that the stoichiometry of the complex between 1 and F− was 1:1 (1:anion) and the stoichiometry of the other complexes studied was 1:3 (1:anion). [Copyright &y& Elsevier]

Abstract: A novel and simple fluorescent receptor bearing thiourea moiety as recognition site was described. The recognition behavior of the receptor toward different anions was investigated in DMSO/H2O (95:5 v/v) and dry DMSO through two various channels: the colorless-yellow color change and a remarkable enhancement of the fluorescence. And the enhancement of the fluorescence was attributed to an anion-induced increase of the rigidity of the host molecule. [Copyright &y& Elsevier]

Abstract: A novel receptor based on phenylhydrazone derivative was developed and applied to the binding anion, showing a common preference for acetate (AcO−) ion, and the preference was related to structure matching between the host and the guest. The receptor exhibited a dramatic color change upon the addition of acetate ions so that we could finish anion recognition by naked eye without resorting to any spectroscopic instruments. The evaluation of the receptor interaction with anions was performed by UV–vis titration experiments with a variety of structurally different anions in DMSO, and the anion binding pattern of the chemosensor was hydrogen bond interactions. [Copyright &y& Elsevier]

Abstract: A new and simple phenylhydrazone-based sensor 1 for acetate has been investigated in DMSO and even in the 95:5 DMSO/H2O (v/v) mixtures. Binding of anions such as AcO−, F− and H2PO4 − results in a noteworthy change in the visible region of spectrum (approximately 100nm red shift), which can be detected by the ‘naked-eye’. The further insights to the nature of interactions between the sensor 1 and AcO− were investigated by 1H NMR titration experiments in DMSO-d 6. In particular, analytical application and detection of acetate ion have been also studied in the aqueous. [Copyright &y& Elsevier]