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.

Effect of magnetic field on radical yields during the photoreduction of xanthene dyes in viscous media

Abstract: The effect of an external magnetic field (H⩽ 0.18 T) on the yield of semiquinone radicals during photoreduction of xanthene dyes (fluorescein, ethyleosine, erithrosine and rose bengal) in a viscous ternary mixture of glycerol, p-cresol and ethanol has been studied by the flash-photolysis technique. The effect of the magnetic field depends upon field strength and solvent viscosity. Magnetic enhancement (an increase of radical yield up to 2.5 times) was observed for dyes in solvents of moderate viscosity [3 ⩽(η/T)/cP K–1⩽ 8]. The influence of internal and external heavy atoms on magnetic field effect in the above-mentioned reactions has been investigated. In the case of fluorescein and erithrosine the existence of an external heavy atom (KI, 0.1 mol dm–3 leads to a decrease in magnetic field effect in contrast to the behaviour of rose bengal. The effect of external heavy atoms on the e.s.r. spectrum of fluorescein-semiquinone radical (HDH˙) has been also studied. Peak broadening and poorer resolution were found in the presence of CsCl for the spectrum of HDH˙. The influence of external heavy atom on the g-factor of free radicals as well as the role of spin–orbit coupling in a magnetic field are discussed.

Antiatherosclerotic sparstolenin B compound and preparation method thereof

Abstract: The invention discloses a new xanthene compound-sparstolenin B of which the chemical structural formula is as follows. The sparstolenin B is obtained by extracting and separating the dried tuber of Sparganium stoleniferum Buch-Ham. The sparstolenin B has the functions of inhibiting migration of arterial smooth muscle cells, inhibiting macrophage-mediated low-density lipoprotein oxidation and inhibiting platelet aggregation activity, and can be used as a medicament for curing and preventing atherosclerosis diseases.

Xanthene organic material and application thereof in devices

Abstract: The invention relates to a xanthene organic material. The xanthene organic material has any structure shown in general formulas I-III. According to the xanthene organic material and the application thereof provided by the invention, peri-xanthenoxanthene is taken as a parent nucleus, and the compound has a relatively wide band gap, a high T1 energy level and a proper highest occupied molecular orbital (HOMO) energy level. The compound has high thermal stability, is not easy to decompose in the sublimation process and has a high glass transition temperature, and the phase stability of the formed film can be maintained. By introducing groups with large steric hindrance, the luminescent material is not easy to crystallize and quench and has good film-forming property. The xanthene organic material provided by the invention is preferably used as a hole transport material of a hole transport layer in an organic electroluminescent device.

Spectral Properties and Photodynamic Activity of Complexes of Polycationic Derivative of Fullerene C60 with Xanthene Dye Fluorescein

Abstract: Using spectrophotometry and stationary and kinetic fluorimetry, we have shown that xanthene dye fluorescein forms complexes with polycationic derivative of fullerene in aqueous solutions mainly due to electrostatic interactions. It is found that efficient quenching of singlet excited states of dye occurs in the structure of these complexes due to the transfer of excitation or electron from dye to fullerene. As a result, the photodynamic activity of the newly formed complex is much higher than that of fluorescein and fullerene derivative. This effect makes it possible to predict the formation of new-generation hybrid photodynamic preparations using dyes excited only into a singlet state; as a result, directed searches for these dyes are significantly facilitated.