Topic
Xanthene
About: Xanthene is a research topic. Over the lifetime, 2132 publications have been published within this topic receiving 34803 citations. The topic is also known as: Xanthene & dibenzo[a,e]pyran.
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17 Mar 2020
TL;DR: In this article, a xanthene-based colorimetric sensor, 2-((5-chloro-2-oxoindolin-3-ylidene)amino)-3',6'-bis(diethylamino)spiro[isoindoline-1,9'-xanthen]-3-one, was designed and its metal sensing properties was evaluated in aqueous solutions.
Abstract: A xanthene-based colorimetric sensor, 2-((5-chloro-2-oxoindolin-3-ylidene)amino)-3',6'-bis(diethylamino)spiro[isoindoline-1,9'-xanthen]-3-one, was designed and its metal sensing properties was evaluated in aqueous solutions. The sensor showed colorimetric response toward Hg2+ from colorless solution to pink among various metal ions such as Na+, K+, Mg2+, Ca2+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Al3+, Cd2+ and Pb2+. The addition of Hg2+ exhibit an absorption enhancement of the sensor based on a spirocycle ring‐opening process and a subsequent hydrolysis reaction. The detection limit of the sensor for Hg2+ was found to be 7.88×10−8 M.
TL;DR: In this paper, it was shown that the presence of an ion in the red spectrum of a red-absorpt ion band is a sign of the involvement of the anion in the formation of a hydrogen bond between the ion and the ion.
Abstract: In p reced ing papers it was shown that dye molecules a re associa ted in solut ions by hydrogen bonds, the product ion of which is revea led in their in f ra red spect r a [1, 2]. The change in the i r e lec t ron ic spect ra , observed on aggregat ion of the dyes, is due, however, to an in tens i f ica t ion of the in te rac t ion between their molecu les in the excited s tate [3]. The magnitude of this in te rac t ion should depend on the mutual a r r a n g e ment of the dye molecules in the associa te [4]. At the same t ime, the p rob lem of the s t ruc tu re of the a s so c ia tes has been insuff ic ient ly d i scussed in the l i t e r a ture; moreover , the authors of those papers which have been published have not taken into account the poss ib i l i ty that the dye molecules are l inked by hydrogen bonds (see, for example, [5]). In the p r e se n t work, we analyzed a la rge amount of exper imenta l ma te r i a l on the cha rac t e r i s t i c fea tures of the assoc ia t ion of molecules of dyes of thexanthene and t r ipheny lmethane s e r i e s to de te rmine the s t ruc tu r e s of the i r assoc ia tes and i ts influence on the v ibra t ional and e lec t ron ic absorpt ion spectra . It is na tura l to begin the study of the s t ruc tu re of the assoc ia tes by es tab l i sh ing the acceptor of the p ro ton of the N----H group of the dye molecules taking par t in hydrogen bond format ion. The degree of a s soc ia tion of rhodamine 6G in b inary mix tures of polar and nonpolar solvents depends to a marked extent on the na ture of the anion [6]. This means that the species combining in the assoc ia tes a re not dye cat ions, but ion pa i r s . Study of the v ibra t iona l spec t ra of rhodamine 6G containing var ious anions has shown that the re la t ive shift and re la t ive in tens i ty of the band, which is a t t r ibuted to the eombinedN----H v ibra t ions with respec t to the band which is a t t r ibuted to f ree N---H v ibra t ions , also depend to a marked extent on the na ture of the anion [7]. This conf i rms the conclusion that the assoc ia t ion of the dyes involves the in te rac t ion of their ion pa i r s and indicates the active role of the anion in the fo r mat ion of dye assoc ia tes . The marked dependence of the in f r a red absorpt ion band on the na ture of the anion suggests that the par t of proton acceptor in the f o r m a t i o n of a hydrogen bond between the ion pa i r s may be played by the anion, which is l inked chiefly by e lec t ro s ta t ic forces to another cation according to the scheme
Patent•
28 Mar 2013
TL;DR: In this article, a spirofluorene xanthene phenol compound and a preparation method for its preparation was provided, which comprises the steps of adding 2,7-dihydroxy fluorenone, phenol, and a catalyst to a container, wherein the molar ratio of the 2.7-Dihydroxyphenol to phenol is 1 to (4-8); the ratio of catalyst to the 2., 7-Dhyno-fluorenone is (0.1-1.0) to 1; heating
Abstract: The invention provides a spirofluorene xanthene phenol compound and a preparation method thereof. The method comprises the steps of adding 2,7-dihydroxy fluorenone, phenol and a catalyst to a container, wherein the molar ratio of the 2,7-dihydroxy fluorenone to the phenol is 1 to (4-8); the ratio of the catalyst to the 2,7-dihydroxy fluorenone is (0.1-1.0) to 1; heating to 120 DEG C to agitate and react for 2 hours; adding concentrated hydrochloric acid, wherein the mass ratio of the concentrated hydrochloric acid to the 2,7-dihydroxy fluorenone is (0.5-1.0) to 1; heating to 140 DEG C, keeping warm and reacting for 3 hours, cooling the product to room temperature, adding water to separate out sediment; washing with deionized water, leaching and drying in vacuum to obtain a crude product; recrystalizing the crude product by using ethanol water of which the volume ratio is 1 to 5 at 80 DEG C, and leaching and vacuum-drying the crystal to obtain the refined product. The novel heat-resistant epoxy resin, polycarbonate and the like synthetized from the compound disclosed by the invention as the material have the characteristics of good heat stability, high transparency, high refractive index, and solubility and the like, and can be widely applied to the preparation of various materials with excellent performances.