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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.


Papers
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Journal ArticleDOI
TL;DR: In this article, the commercial catalyst Amberlyst-15, an inexpensive, safe to handle and easy to recycle sulfonic resin, was used for the oxidative coupling of xanthene and thioxanthene with methylene active compounds.

28 citations

Journal ArticleDOI
TL;DR: In this paper, a highly stable and environmentally benign phosphate anchored MnO2 (P-MnO2) catalyst has been developed for the synthesis of 1,8-dioxooctahydroxanthene and 14-aryl (alkyl)-14H-dibenzo[a,j]xanthene laser dye derivatives under solvent free conditions.
Abstract: A highly stable and environmentally benign phosphate anchored MnO2 (P-MnO2) catalyst has been prepared. The catalyst has been characterized by using TGA, FTIR, Raman, XRD, UV-DRS, XPS, FESEM, and EDAX techniques. The catalytic behavior of P-MnO2 has been demonstrated for the synthesis of 1,8-dioxooctahydroxanthene and 14-aryl (alkyl)-14H-dibenzo[a,j]xanthene laser dye derivatives under solvent free conditions. Recyclability, high yield, short reaction time, relative non-toxicity and easy workup are the advantages of the presented catalyst.

28 citations

Journal ArticleDOI
TL;DR: DFT calculations suggest that this species features NiI centers antiferromagnetically coupled to each other and their iminopyridine ligand radicals, including structures of putative dinuclear metallocyclopentadiene and met allocycloheptatriene intermediates.
Abstract: The reaction of a dinucleating bis(iminopyridine) ligand L bearing a xanthene linker (L = N,N'-(2,7-di-tert-butyl-9,9-dimethyl-9H-xanthene-4,5-diyl)bis(1-(pyridin-2-yl)methanimine)) with Ni2(COD)2(DPA) (COD = cyclooctadiene, DPA = diphenylacetylene) leads to the formation of a new dinuclear complex Ni2(L)(DPA). Ni2(L)(DPA) can also be obtained in a one-pot reaction involving Ni(COD)2, DPA and L. The X-ray structure of Ni2(L)(DPA) reveals two square-planar Ni centers bridged by a DPA ligand. DFT calculations suggest that this species features NiI centers antiferromagnetically coupled to each other and their iminopyridine ligand radicals. Treatment of Ni2(L)(DPA) with one equivalent of ethyl propiolate (HCCCO2Et) forms the Ni2(L)(HCCCO2Et) complex. Addition of the second equivalent of ethyl propiolate leads to the observation of cyclotrimerised products by 1H NMR spectroscopy. Carrying out the reaction under catalytic conditions (1 mol% of Ni2(L)(DPA), 24 h, room temperature) transforms 89% of the substrate, forming primarily benzene products (triethyl benzene-1,2,4-tricarboxylate and triethyl benzene-1,3,5-tricarboxylate) in 68% yield, in a ca. 5 : 1 relative ratio. Increasing catalyst loading to 5 mol% leads to the full conversion of ethyl propiolate to benzene products; no cyclotetramerisation products were observed. In contrast, the reaction is significantly more sluggish with methyl propargyl ether. Using 1 mol% of the catalyst, only 25% conversion of methyl propargyl ether was observed within 24 h at room temperature. Furthermore, methyl propargyl ether demonstrates the formation of cyclooctatetraenes in significant amounts at a low catalyst concentration, whereas a higher catalyst concentration (5 mol%) leads to benzene products exclusively. Density functional theory was used to provide insight into the reaction mechanism, including structures of putative dinuclear metallocyclopentadiene and metallocycloheptatriene intermediates.

28 citations

Journal ArticleDOI
TL;DR: In this paper, a novel fluorescent chemosensor L has been designed and synthesized based on the rhodamine-B moiety, which exhibits selective fluorescence enhancement towards the Al3+ ion over other biologically relevant metal ions in aqueous ethanolic media.
Abstract: A novel fluorescent chemosensor L has been designed and synthesized based on the rhodamine-B moiety. The dye L exhibits selective fluorescence enhancement towards the Al3+ ion over other biologically relevant metal ions in aqueous ethanolic media (EtOH–H2O, 2 : 3, v/v). The structure of the probe L has been established by 1H and 13C-NMR spectroscopy, single crystal X-ray diffraction, ESI-mass spectrometry and elemental analysis. The cleavage of the spirolactam bond of the rhodamine moiety induced by the Al3+ ion generates the delocalized xanthene fluorophore that is responsible for the emission enhancement of the probe L. The recognition behavior of the receptor L has been investigated experimentally with supports from theoretical DFT studies. Furthermore, the efficacy of L in cell imaging studies is also probed by confocal microscopy.

28 citations

Journal ArticleDOI
TL;DR: This paper showed that acidic catalysis plays a significant role in promoting the cleavage of the C−O bond in a 16 VE complex featuring an allyl ether as η2-ligand.

28 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202354
2022136
202182
202091
201986
201891