Palladium-catalysed amination of bromofluorans and an investigation of their thermochromic behaviour

Azizian, Farid; Field, Amanda J.; Griffiths, J.; Heron, B. Mark

doi:10.1016/j.dyepig.2011.06.018

Cited by 12 publications

(3 citation statements)

References 40 publications

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“…Compared with polyene molecules (traditional 2PA chromophores), merocyanine dyes may have more efficient intramolecular charge transfer (ICT) between the donor and acceptor and hence higher dipole moment (or polarization) in the ground state as well as larger 2PA cross-section for the shorter conjugated chain . Overall, only a few papers on merocyanine dyes in conjunction with two-photon absorption have been published. − Whereas rhodamine and fluorescein dyes have been widely studied, rhodol derivatives are more rarely mentioned in the literature. − Furthermore, to the best of our knowledge, no rhodol dyes were studied in terms of their 2PA properties. Thus, we resolved to use rhodol fluorophore bearing an additional heterocyclic unit at position 9, since (a) this position is the easiest to functionalize and (b) flexibility of the synthesis of five-membered aromatic heterocycles offers straightforward way to modify linker if necessary to fine-tune optical properties.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Optical Chemosensor for Sodium Ion Based on Rhodol Chromophore

et al. 2013

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As part of a strategy to identify good fluorescent probes based on two-photon excited fluorescence (TPEF), the sensor for sodium cation has been designed bearing a rhodol chromophore linked with an aza-crown ether. An efficient synthetic route to rhodol derivatives possessing five-membered heterocycles at position 9 and their precursors that contain xanthylium salt has been developed. The synthesis involves condensation of xanthylium salts bearing vinamidinium moiety at position 9, with phenylhydrazine derivatives as the key step. To accomplish the synthesis of derivatives bearing 1-aza-15-crown-5 and 1,10-diaza-18-crown-6, the Buchwald-Hartwig reaction has been employed in the final stage. Electronic spectra of all prepared rhodols display strong absorption in the range of 450-550 nm with well-resolved vibronic bands, which maintains its fine structure in a wide range of solvents. The most intensive two-photon absorption (2PA) band in the rhodol spectrum (165 GM), located at shorter wavelengths, matches well with the short-wavelength absorption band in the linear electronic spectrum and is most probably related to the two-photon allowed electronic transition S0→S2. The influence of cation binding on one- and two-photon spectroscopic properties of rhodol linked with 1-aza-15-crown-5 via the phenylpyrazole bridge has been investigated. This probe exhibits high sensitivity and good selectivity for Na(+) in CH3CN. The mechanism involves the complexation of the Na(+) by 1-aza-15-crown-5 in the probe, which induces prominent fluorescence enhancement via quenching of electron-transfer. Interestingly, the complexation with Na(+) led to a significant increase of the 2PA band in the 750-800 nm region (corresponding to a two-photon allowed, one-photon forbidden transition) for rhodol bearing 1-aza-15-crown-5, which led to the overall enhancement of the TPEF signal (approximately an order of magnitude). Thus, a turn-on fluorescent probe for sodium ion, which does not respond to many other metal species, has been constructed.

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Section: Introductionmentioning

confidence: 99%

Nonlinear Optical Chemosensor for Sodium Ion Based on Rhodol Chromophore

et al. 2013

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“…We have recently reported the use of Pd-mediated amination [4] and Pd-mediated hydroxyarylation [5] for the functionalization of a series of bromo(benzo)fluorans. The latter account described the synthesis of a series of hydroxyaryl benzofluorans which exhibited thermochromism without the need of the established colour developer bisphenol A when formulated in methyl stearate.…”

Section: Introductionmentioning

confidence: 99%

Reductive alkylation of aminofluorans: A simple route to intrinsically thermochromic fluorans

2013

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“…In organic thermochromic materials, leuco dyes are highly interested and changed from a colorless to a colored state by accepting a proton. Rhodamine B derivatives, , fluorans, − spiropyrans, − and crystal violet lactone are some important examples of leuco dye compounds that are generally used in the preparation of thermochromic materials. , Thermochromism is classified into reversible and irreversible categories, where the reversible systems have gained more attention because of their extensive applications based on temperature fluctuations during the day and in different seasons, such as in the military, construction, anticounterfeiting, sensors, etc . For the reversible coloration–decoloration of organic leuco dyes, a three-component system including leuco dye, solvent, and developer is required. , Color developers play the role of chroma, and are often from the category of phenolics (a weak acid such as Bisphenol A), aromatic amines, lauryl gallate, ethyl gallate, carboxylic acids, and Lewis acids that are usually used for the solid state of the thermochromic materials. ,− Strong proton donors, such as hydrochloric acid, are suitable for both liquid and solid states, and they provide a proton to the color former.…”

Section: Introductionmentioning

confidence: 99%

Thermal-Induced Chromism and Fluorescence Emission of Rhodamine B-Containing Polymers with Different Polarities: Tracking Temperature and Development of Thermochromic Labels

Babazadeh-Mamaqani,

Mohammadi-Jorjafki,

Alipour-Fakhri

et al. 2023

Macromolecules

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Thermochromic polymers, as a highly applicable intelligent category of innovative materials, are capable of changing their color with temperature variations. Different characteristics of the matrix and specially its polarity can be influential factors in the responsivity of thermochromic polymers. In this study, polystyrene, poly(methyl methacrylate), and poly(dimethylaminoethyl methacrylate) with different polarities were synthesized via reverse atom transfer radical polymerization. Thermochromic polymers were prepared by physical incorporation of the N-(rhodamine-B)lactam-ethylenediamine leuco dye and HCl color developer into the three polymers. The effect of polarity of the polymers on their thermochromism and fluorescence properties was investigated. The thermochromic polymers changed their color from colorless to a colored state with increasing temperature due to the intermolecular proton transfer in the system. UV−vis and fluorescence spectroscopies were used to evaluate the thermochromism and fluorescence properties of the polymer systems, respectively, at different temperatures. The intensity of absorption and emission of the thermochromic polymers increases with increasing temperature, where increasing polarity of the polymer matrix has an opposite effect on the intensity of absorption and emission. The change in color with temperature variation was detectable with the naked eye for the three polymer samples. In addition, investigation of the fatigue resistance and also response and recovery times of the samples showed temperature-sensing ability of the samples. These results showed that all samples have high responsivity and coloration for at least 10 heating−cooling cycles. Biocompatible thermochromic cellulosic papers were also fabricated, which showed irreversible coloration at different temperatures due to the removing solvent. Chromic labels with the ability of irreversible thermal-induced chromism was used as preservation taggants, which indicate that the food materials were kept at the right or wrong temperature. Therefore, they have a high potential for applications in various fields, such as temperature sensors, condition preservation taggant or labels for food or cosmetic, and anticounterfeiting inks.

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Palladium-catalysed amination of bromofluorans and an investigation of their thermochromic behaviour

Cited by 12 publications

References 40 publications

Nonlinear Optical Chemosensor for Sodium Ion Based on Rhodol Chromophore

Nonlinear Optical Chemosensor for Sodium Ion Based on Rhodol Chromophore

Reductive alkylation of aminofluorans: A simple route to intrinsically thermochromic fluorans

Thermal-Induced Chromism and Fluorescence Emission of Rhodamine B-Containing Polymers with Different Polarities: Tracking Temperature and Development of Thermochromic Labels

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