- Responsive ruthenium complex probe for phosphorescence and time-gated luminescence detection of bisulfite
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Sensitive and selective quantification of specific analytes is of great significance in analytical and environmental sciences, as well as in the food industry. Herein, we report the design, synthesis, characterization, and application of a responsive ruth
- Du, Zhongbo,Liu, Chaolong,Liu, Jianping,Song, Bo,Wang, Yong-Lei,Xi, Xiuyan,Yuan, Jingli,Zhang, Run,Zhang, Wenzhu
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p. 5531 - 5538
(2020/05/13)
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- Solvatochromism of new substituted 4-[(E)-(4-nitrophenyl)diazenyl]phenolate dyes
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Studies on the reverse solvatochromism of dyes in pure solvents are of interest to gain a better understanding of the nature of this phenomenon. In this paper, a series of nine compounds, exhibiting phenol and 4-nitrophenyl groups linked with an azo conjugated bridge, was synthesized and characterized. These compounds were deprotonated to generate solvatochromic phenolate dyes. The azo bridge makes the phenol more acidic, in comparison with the related compounds exhibiting a CH[dbnd]CH or CH[dbnd]N bridge in their molecular structure, indicating the electron withdrawing character of the azo bridge. The solvatochromism of the dyes was investigated in 29 solvents and their intense colors in solution were attributed to π-π* electronic transitions, with an intramolecular charge transfer from the phenolate towards the 4-nitroaryl group. The probes exhibited a reversal in their solvatochromism, in a similar fashion to the behavior verified with related dyes presenting CH[dbnd]CH or CH[dbnd]N as the conjugated bridge; however, the azo dyes are much less sensitive to solvent polarity changes. Multiparametric analysis showed that the azo dyes are very sensitive to the acidity of the medium, but still to a lesser degree than the corresponding imine and stilbene dyes, due to the electronegativity of the azo group. The reverse solvatochromism of the dyes is dictated by the electron-donor phenolate and by the electron-acceptor 4-nitroaryl groups, independently of the conjugated bridge, of the additional nitro group and of the nature of substituents in the 2,6-positions of the phenolate groups. Thus, the solvatochromic reversal verified represents a committed step involving the interaction of the nitro and phenolate groups in the probe with the molecules of structurally different solvents.
- de Melo, Carlos E.A.,Nicoleti, Celso R.,Nandi, Leandro G.,Schneider, Felipe S.S.,da S. Oliboni, Robson,Caramori, Giovanni F.,Machado, Vanderlei G.
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- A method of preparing azo dye through coupling
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The invention relates to an azo dye synthetic method, and particularly relates to a method of coupling a weak-alkaline arylamine diazonium salt and a phenol compound under alkaline conditions to prepare azo dye. Weak-alkaline arylamine diazonium salt filt
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Paragraph 0039-0042
(2018/05/30)
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- BASIC PROPERTIES OF 4-ARYLAZO-PHENOLS AND 4-ARYLAZO-ANISOLES
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The conditions in which 4-arylazo-phenols and 4-arylazo-anisoles have basic properties have been studied.We have also determined the equilibrium constants of the reactions between 4-arylazo-phenols or 4-arylazo-anisoles with perchloric acid in nitromethane, acetonitrile and acetic acid.Conclusions have been drawn from the influence of the nature of solvent and substituent at the benzene ring on equilibrium constant values.
- Nesterowicz, Marianna,Korewa, Ryszard
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p. 1085 - 1092
(2007/10/02)
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