Topic
Auxochrome
About: Auxochrome is a research topic. Over the lifetime, 82 publications have been published within this topic receiving 1334 citations.
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16 Jan 2013
TL;DR: The most common auxochromes are amine, carboxyl, sulfonate and hydroxyl as mentioned in this paper, which are based on diverse functional groups, such as azo, anthraquinone, methine, nitro, aril‐ methane, carbonyl and others.
Abstract: Dyes may be defined as substances that, when applied to a substrate provide color by a process that alters, at least temporarily, any crystal structure of the colored substances [1,2]. Such substances with considerable coloring capacity are widely employed in the textile, pharmaceutical, food, cosmetics, plastics, photographic and paper industries [3,4]. The dyes can adhere to compatible surfaces by solution, by forming covalent bond or complexes with salts or metals, by physical adsorption or by mechanical retention [1,2]. Dyes are classified according to their application and chemical structure, and are composed of a group of atoms known as chromophores, responsible for the dye color. These chromophore-containing cen‐ ters are based on diverse functional groups, such as azo, anthraquinone, methine, nitro, aril‐ methane, carbonyl and others. In addition, electrons withdrawing or donating substituents so as to generate or intensify the color of the chromophores are denominated as auxo‐ chromes. The most common auxochromes are amine, carboxyl, sulfonate and hydroxyl [5-7].
441 citations
TL;DR: Four novel borondipyrromethene and -diindomethene dyes with one or two (dimethylamino)styryl extensions at the chromophore were synthesized and spectroscopically investigated and showed remarkable switching of lipophilicity by protonation.
Abstract: Four novel borondipyrromethene (BDP) and -diindomethene (BDI) dyes with one or two (dimethylamino)styryl extensions at the chromophore were synthesized and spectroscopically investigated. An X-ray crystal structure shows that the extended auxochrome is virtually planar. All dyes thus display intense red/near infrared (NIR) absorption and emission. The (dimethylamino)styryl group induces a charge-transfer character that entails bright solvatochromic fluorescence, which is only quenched with increasing solvent polarity according to the energy-gap law. The dye with an additional dimethylanilino group at the meso position of BDP shows a remarkable switching of lipophilicity by protonation. Two dyes with an 8-hydroxyquinoline ligand at the meso position display quenched emission in the presence of Hg2+ or Al3+ owing to electron transfer from the excited BDP to the complexed receptor. The BDI dye presents a pH indicator with bright fluorescence and extremely low fluorescence anisotropy.
140 citations
TL;DR: Unprecedented regioselective post-functionalization of racemic and enantiopure cationic diaza [4]helicenes is afforded.
Abstract: Unprecedented regioselective post-functionalization of racemic and enantiopure cationic diaza [4]helicenes is afforded. The peripheral auxochrome substituents allow a general tuning of the electrochemical, photophysical and chiroptical properties of the helical dyes (26 examples). For instance, electronic absorption and circular dichroism are modulated from the orange to near-infrared spectral range (575–750 nm), fluorescence quantum efficiency is enhanced up to 0.55 (631 nm) and circularly polarized luminescence is recorded in the red (|glum| ∼ 10−3).
83 citations
TL;DR: In this paper, the most common chromophores areazo, nitro, and carbonyl groups and Auxochromes, functional groups that increase the intensity of the color, are also important parts of dyes.
Abstract: In this review paper, we talk about Dyes are used to give colors to substances, especially fabrics. Chromophores, functionalgroups that absorb light, give color to these dyes. The most common chromophores areazo, nitro, and carbonyl groups. Auxochromes, functional groups that increase theintensity of the color, are also important parts of dyes. The most common chromophoresare hydroxyl, amino, sulfonate, and carboxylate groups.Azo dyes have a nitrogen to nitrogen double bond as their chromophore. These dyes arecreated by taking a diazonium salt and adding it to a strongly activated aromatic system.
83 citations
TL;DR: In this paper, the authors synthesized a photoswitchable fluorescent probe incorporating a coumarin fluorophore and an oxazine photochrome within the same molecular skeleton, which can be used for photoactivation.
Abstract: We synthesized a photoswitchable fluorescent probe incorporating a coumarin fluorophore and an oxazine photochrome within the same molecular skeleton. The visible illumination of this fluorophore−photochrome dyad results in the excitation of the fluorescent component only if the photochromic element is activated with ultraviolet irradiation. Indeed, the photoinduced opening of the oxazine ring bathochromically shifts the absorption of the coumarin fragment sufficiently to encourage its visible excitation with concomitant fluorescence. These operating principles translate into fluorescence photoactivation with good contrast ratio and brightness as well as short fluorescence lifetime. The modular character and relative simplicity of this synthetic strategy for the assembly of photoswitchable constructs might evolve into a general design logic for the photoregulation of the electronic structure of a given chromophore with a photochromic auxochrome.
60 citations