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, two-fold lithiation of 9,9-dimethylxanthene with n-butyllithium and N,N,N N′,N′, N′-tetrametylethylenediamine (TMEDA) in boiling n-heptane followed by reaction with chlorodiphenylphosphine (Ph2PCl) yielded the title compound 4.1
80 citations
TL;DR: In this article, the synthesis of novel xanthene-based hydrazone (1) was resolved using spectroscopic techniques such as NMR, FT-IR, UV-VIS and X-ray crystallographic approaches.
78 citations
TL;DR: In this article, the photovoltaic properties of nanostructured ZnO electrodes with xanthene dyes are explored and compared to that of the more common N719 dye.
Abstract: The photovoltaic properties of nanostructured ZnO electrodes prepared from commercially available ZnO nanoparticles (Degussa) and sensitised with xanthene dyes are explored. We have used Eosin Y, Eosin B and Mercurochrome and compared their performance to that of the more common N719 dye. We observe that these dyes efficiently sensitise commercial ZnO nanopowder and yield efficiencies that are very competitive with respect to those provided by N719. Local photocurrent and transmittance measurements as a function of the wavelength confirm the good performance of the xanthene dyes in the absorption maxima. We have prepared polymer-sealed cells and measured the short-circuit current of the devices under continuous illumination at 200 mW/cm2 corresponding to twice the standard solar light intensity. The organic dyes show very good stability properties under these conditions. The combination of a versatile metal oxide such as ZnO and inexpensive organic dyes should be considered as a promising alternative in the field of dye-sensitised solar cells.
78 citations
TL;DR: In this article, the triplet states of xanthene dyes undergo energy-transfer and electron-transfer, but with rate constants differing by two orders of magnitude in favour of the former pathway.
Abstract: — Some photochemical and photophysical properties of a group of xanthene dyes have been studied in relation to their roles as sensitizers for the photoreduction of water. New spectroscopic and kinetic measurements have been carried out with these dyes. The triplet states of the dyes undergo energy-transfer and electron-transfer, but with rate constants differing by two orders of magnitude in favour of the former pathway. The very efficient transfer of triplet energy from a group of dyes to an acceptor molecule led to the design of a greatly improved system for the photochemical production of hydrogen.
77 citations
TL;DR: In this paper, the elongated central C9-C10 bond is cleaved to give the biphenyl-2,2′-diyl bis(xanthenylium) dye 2a2+, which regenerates the colorless dispiro compound 1a by two-electron reduction.
Abstract: Upon two-electron oxidation of the title electron donor 1a, the elongated central C9–C10 bond [1.656(5)
A
(X-ray)] is cleaved to give the biphenyl-2,2′-diyl bis(xanthenylium) dye 2a2+, which regenerates the colorless dispiro compound 1a by two-electron reduction. The presence of isosbestic points in the UV–Vis spectra during the electrochemical oxidation of 1a to 2a2+ indicates the negligible steady-state concentration of the intermediate cation radical. Interconversion between optically resolved 1a and 2a2+ is accompanied by drastic changes in the CD spectra again with several isosbestic points, and racemization of (P)- and (M)-1a and (S)- and (R)-2a2+ does not occur at ambient conditions. This redox pair represents a new motif for the multi-output response system, where the electrochemical input is transduced into two independent spectral outputs.
76 citations