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.

Photosensitization of Colloidal SnO2 Semiconductor Nanoparticles with Xanthene Dyes

Abstract: The photochemical behavior of xanthene dyes (fluorescein, erythrosine, and eosin) with colloidal SnO2 nanoparticles was probed by UV-visible, steady state, and time resolved fluorescence measurements. The prepared SnO2 nanoparticles were characterized by using UV-visible and powder XRD measurements. The xanthene dyes were adsorbed on the surface of colloidal SnO2 nanoparticles through electrostatic interaction. Apparent association constant () was calculated from the relevant fluorescence data. The larger value of apparent association constant indicates a strong association between xanthene dyes and SnO2 nanoparticles. The fluorescence quenching is mainly attributed to electron transfer from the excited state xanthenes to the conduction band of colloidal SnO2. The electron transfer mechanism was explained based on the Rehm-Weller equation as well as the energy level diagram.

New strategy of synthesis, characterization, theoretical study and inhibition effect on mild steel corrosion in acidic solution

Abstract: We report two new different synthesis strategies of an eco-friendly organic dye 3-oxo-3H-spiro[isobenzofuran-1,9'-xanthene]-3',6'-diyl diacetate. These methods were based on the reaction of fluorescein with acetic anhydride under different experimental conditions. The synthesized heterocyclic system obtained with excellent yield was characterized by FT-IR, 1 H N.M.R., 13 C N.M.R., and mass spectrometry. This reaction has also been studied theoretically using Gaussian 09 based on the DFT method at B3LYP/6-31G (d, p). The results obtained are in good correlation with those obtained experimentally. The inhibition behavior of the synthetic product has been studied using absorbance difference measurement, the percentage of inhibition efficiency attains 90% at 10 -4 M of NAR3 inhibitor. The surface analysis of mild steel was investigated using scanning electron microscopy (S.E.M.) and Energy Dispersive X-ray (E.D.X.) methods and show the adsorption behavior of inhibitor on the surface of mild steel.

Enzyme detection method and reagent

Abstract: The invention provides a method for determining nitroreductase activity, the method comprising combining a substrate comprising a compound of formula (I): wherein groups Ra and Rb are attached to atoms of the Z ring system; Z represents the a chain of linked atoms necessary to complete an aromatic or heteroaromatic ring system having five or six atoms selected from carbon atoms and optionally no more than two atoms selected from oxygen, nitrogen and sulphur; FLUOR is a fluorescent dye selected from xanthene, coumarin and oxazine dyes; L1 is a bond or is an atom or a chain of 2 to 10 covalently linked atoms selected from the group consisting of carbon, nitrogen, oxygen and sulphur atoms; each Ra is hydrogen or may be selected from electron donating and withdrawing groups, and p is 0 or an integer from 1 to 3; Rb is hydrogen or is the group -L2-W, where L2 is a linker chain containing from 1-20 linked atoms and W is a fluorescent dye moiety or a quenching group; m is 0 or 1; and r is 1 or 2; with a sample containing or suspected to contain nitroreductase under conditions to cause cleavage of FLUOR from the substrate. Nitroreductase activity is determined by detecting a change in an optical property of the sample.

Polarized Absorption Spectra and Configuration Analyses of Xanthene and Xanthone

Abstract: The polarized absorption sepctra of xanthene and xanthone were measured in stretched poly (vinyl alcohol) films, and the polarization direction of each electronic transition was determined. It was confirmed that xanthone has the short molecular-axis polarized bands (1A1←1A1) at 343, 260, and 226 nm, and the long molecular-axis polarized ones (1BA2←1A1) at 290, 266, and 242 nm. The electronic transitions of xanthone are discussed in connection with those of xanthene by use of the configuration analysis. For the 266 and 260 nm bands, the contributions of the intramolecular charge transfer character from the xanthene skeleton to the carbonyl group are considerable.

Electrically doped organic semiconducting material and organic light emitting device comprising it

Abstract: The invention relates to electrically doped semiconducting material comprising iii) at least one electrical dopant selected from metal salts consisting of at least one metal cation and at least one anion and iv) at least one matrix compound of formula 1 wherein each of R 1 , R 2 , R 1 , R 2′ is independently selected from H, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl and C 6 -C 14 aryl or both substituents on the same aromatic ring of the xanthene skeleton are hydrocarbyl groups linked with each other to form together an anelated divalent C 2 -C 10 hydrocarbyl group and A and A′ are independently selected from C 1 -C 20 heteroaryl group comprising at least one sp 2 hybridized nitrogen atom as well as an electronic device and a compound.