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: Thin films of three differently charged xanthene dyes were cast onto a polystyrene (PS) coated glass substrate to investigate ion-π interactions, and the formation of a weakly emissive exciplex was found for Rh6G and DSF, consistent with ion- π interactions, but no evidence of anexciplex is found for the F27 films.
Abstract: Thin films of three differently charged xanthene dyes: rhodamine 6G (Rh6G, cationic), fluorescein 27 (F27, neutral), and disodium fluorescein (DSF, anionic) were cast onto a polystyrene (PS) coated glass substrate to investigate ion-π interactions. Absorbance spectroscopy was used to determine the aggregation state of the dyes on the PS surface. Deconvolution of the spectra of films revealed multiple peaks for all dyes assigned to isolated monomers, aggregates, and complexes between the dye and the polymer substrate. The shift of the low energy peak relative to the monomer peak was used as an indication of interaction strength of that species with the PS π system, which followed the trend of Rh6G > DSF > F27. Increase in the interaction energy is attributed to stabilization from ion-π interactions. Steady-state emission spectra and excited state lifetime measurements were performed on all films. The formation of a weakly emissive exciplex was found for Rh6G and DSF, consistent with ion-π interactions, but no evidence of an exciplex is found for the F27 films.
4 citations
TL;DR: In this article, the synthesis of two functionalized xanthenes is described, which after deprotonation represent ligands for dinuclear metal complexes, and the crystal structures of 4 and 5 are discussed.
Abstract: The syntheses of two functionalized xanthenes are described which after deprotonation represent ligands for dinuclear metal complexes. For the previously prepared [ᴿXanthdim]H₂ - which after deprotonation leads to a ligand with two adjacent β -diiminato binding sites - a significantly improved synthetic procedure is described involving the Pd catalyzed coupling of two diethyl malonate moieties to the xanthene backbone. Deprotonation of the resulting compound [Xanthmal]H2 provides a ligand with two adjacent diethyl malonate functions. To demonstrate this, [Xanthmal]H₂ was reacted exemplarily with two equivalents of LDA to obtain the lithium salt {Li₂[Xanthmal]}2 (4) which can be treated with ZnBr₂ to yield the zinc complex [Xanthmal]₂Zn₂ (5). Alternatively, 5 can be obtained directly from [Xanthmal]H₂, when ZnEt₂ is chosen as the metal precursor. The crystal structures of 4 and 5 are discussed. In summary, the results show that [Xanthmal]²⁻ is a suitable ligand for the preparation of novel dinuclear metal complexes.
4 citations
TL;DR: In this article, the authors reported the use of recently developed oxidised polyethylene (PEOX) stretched film linear dichroism to determine the transition polarizations of xanthene, 9-methyl-2,3,7-trihydroxy-6-fluorone, pyronin Y, Pyronin B, fluorescein, and rhodamine 6G.
Abstract: Xanthene dyes are commonly used to label proteins in order to probe their location and activity using fluorescence spectroscopy and microscopy. However, fundamental properties such as the polarizations of transitions for many of the dyes have not been available. In this paper we report the use of recently developed oxidised polyethylene (PEOX) stretched film linear dichroism to determine the transition polarizations of xanthene, 9-methyl-2,3,7-trihydroxy-6-fluorone, pyronin Y, pyronin B, fluorescein, and rhodamine 6G. The effect of the formation of higher order structures is also discussed when they occur. The dyes (except xanthene) all have an intense long-axis polarized transition in the region of 500 nm. They also have long-axis (//) polarized transitions from about 280 nm downwards in wavelength. There are suggestions of a weak short axis (⊥) polarized transition in the region of 320–350 nm in each case.
4 citations
TL;DR: Glycerol was used, for the first time, as a green and effective promoting medium for electrophilic activation of aldehydes, and with which, a catalyst-free system for some reactions that conventionally carried out using acid catalysts, such as synthesis of di(indolyl)methanes, 3,4,5,6,7,9-hexahydro-9-aryl-1H-xanthene-1,8(2H)-dione and 1-oxo-hexaphroxanthenes, was developed
Abstract: Glycerol was used, for the first time, as a green and effective promoting medium for electrophilic activation of aldehydes, and with which, a catalyst-free system for some reactions that conventionally carried out using acid catalysts, such as synthesis of di(indolyl)methanes, 3,4,5,6,7,9-hexahydro-9-aryl-1H-xanthene-1,8(2H)-dione and 1-oxo-hexahydroxanthenes, was developed.
4 citations
TL;DR: In this article, the authors obtained 10-cyclopropyl-7-fluoro-1-hydroxy-6-(4-methyl-1iperazinyl)-9 H -xanthen-9-one (IVd) from corresponding difluoro derivatives IVa and IVb, respectively, via 3,4-dihydro-1,9(2 H )-diones Va and Vb.
Abstract: Target 10-cyclopropyl-7-fluoro-1-hydroxy-6-(4-methyl-1-piperazinyl)acridin-9(10 H )-one ( IVc ) and 7-fluoro-1-hydroxy-6-(4-methyl-1-piperazinyl)-9 H -xanthen-9-one ( IVd ) were obtained from corresponding difluoro derivatives IVa and IVb , respectively. These intermediates were synthesized via respective 3,4-dihydro-1,9(2 H )-diones Va and Vb . Acridine derivative (10-cyclopropyl-6,7-difluoro-3,4-dihydro-1H-acridine-1,9(2H,10H)-dione, Va) was synthesized from 1-cyclopropyl-6,7-difluoroisatoic anhydride ( XI ) and xanthene derivative (6,7-difluoro-3,4-dihydro-1 H -xanthen-1,9(2 H )-dione, Vb ) from cyclohexenone derivative VIb . Several unsuccessful attempts to prepare hydroxyacridone IVc and/or some useful intermediates of its synthesis are also described.
4 citations