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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TL;DR: In this article, the quantum yield of the direct and sensitized photoreduction (Φs) was compared, on the basis of the following relations,Φ=\varphiSTAβ Φs= \varphiSTDγβ, where β is the fraction of triplet dye molecules that are reduced eventually, and γ is the energy transfer efficiency.
Abstract: Intersystem crossing probability, \varphiSTA for fluorescein, eosine, erythrosine, methylene blue and thionine in ethanol (only for fluorescein, 30 vol% alkaline aqueous ethanol solution), has been determined by comparing the quantum yield of the direct (Φ) and sensitized photoreduction (Φs), on the basis of the following relations,Φ=\varphiSTAβ Φs=\varphiSTDγβwhere β is the fraction of triplet dye molecules that are reduced eventually, \varphiSTA and \varphiSTD are respectively for acceptor (dye) and donor (sensitizer) and γ is the energy transfer efficiency, which was assumed as 1. ATU was used as a reducing agent. 1,2,5,6-dibenzanthracene, triphenylene, anthracene and β-acetonaphthone were used as sensitizers. It has been confirmed that the above relations and assumption hold generally. Different sensitizers usually gave nearly the same \varphiSTA values (with the exception of thionine-anthracene. β-Acetonaphthone gave in general somewhat smaller values). The most probable \varphiSTA values obtained ar...
63 citations
TL;DR: In this article, a short, efficient synthetic route has been developed for the preparation of 2,7-dibromospiro[fluorene-9,9-9]-(2',7'-di-n-octyloxyxanthene)], which was subsequently polymerized with the corresponding diborolane through Suzuki coupling to afford a fluorene based homopolymer, PSFX, that contains a spiro-fused xanthene group functionalized on the C-9 position of each repeat unit.
Abstract: A short, efficient synthetic route has been developed for the preparation of 2,7-dibromospiro[fluorene-9,9‘-(2‘,7‘-di-n-octyloxyxanthene)], which was subsequently polymerized with the corresponding diborolane through Suzuki coupling to afford a fluorene-based homopolymer, PSFX, that contains a spiroxanthene group functionalized on the C-9 position of each fluorene repeat unit. Single-crystal X-ray diffraction analysis of the dibromo monomer revealed that the spiro-fused fluorene and xanthene moieties lie perpendicular to one another. As a consequence of the incorporation of the spiro pendant group, PSFX possesses a high glass transition temperature and good thermal stability while displaying its stable blue emission in the solid state. A light-emitting diode device prepared using PSFX as the emitting layer exhibits an efficient, stable blue emission; it has a turn-on voltage of 6 V and a maximum external quantum efficiency of 1.74% ph/el. Even when the brightness was increased up to 103 cd/m2 (ca. 11 V), ...
62 citations
TL;DR: In this paper, an efficient and facile synthesis of biologically active 14-substituted-14-H-dibenzo[a,j] xanthene derivatives was reported via three-component condensation reaction of β-naphthol and aldehydes in the presence of a catalytic amount of Preyssler type heteropoly acid, under solvent-free conditions.
Abstract: An efficient and facile synthesis of biologically active 14-substituted-14-H-dibenzo[a,j] xanthene derivatives were reported via three-component condensation reaction of β-naphthol and aldehydes in the presence of a catalytic amount of Preyssler type heteropoly acid, under solvent-free conditions. This method is very easy, rapid and high yielding reaction for the synthesis of dibenzo xanthene derivatives.
62 citations
TL;DR: A new class of rhodamines for the application as indicator dyes in fluorescent pH sensors is presented, which derives from photoinduced electron transfer between non-protonated amino groups and the excited chromophore which results in effective fluorescence quenching at increasing pH.
61 citations
TL;DR: The relationship between the spirolactam ring-opening process of rhodamine derivatives and the structure of the xanthene moiety is examined and a new fluorescence probe for Zn(2+) sensor is developed.
61 citations