Azaxanthones and azathioxanthones are effective sensitisers for europium and terbium luminescence
作者:Paul Atkinson、Karen S. Findlay、Filip Kielar、Robert Pal、David Parker、Robert A. Poole、Horst Puschmann、Siobhan L. Richardson、Philip A. Stenson、Amber L. Thompson、Junhau Yu
DOI:10.1039/b601357k
日期:——
Several azaxanthone and azathioxanthone sensitising chromophores have been incorporated into macrocyclic ligands and form well-defined Eu and Tb complexes in polar media. Excitation of the heterocyclic chromophore in the range 330 to 382 nm leads to modest amounts of aromatic fluorescence and relatively efficient metal-based luminescence, with absolute metal-based quantum yields of up to 24% in aqueous media.
Synthesis of 1-Azaxanthones and 1-Azathioxanthones by Yb(OTf)3/TfOH Co-Catalyzed Intramolecular Friedel-Crafts Reaction
作者:Weike Su、Can Jin、Jie Li
DOI:10.3987/com-10-12029
日期:——
Intramolecular Friedel-Crafts cyclization of phenoxypyridine acids (3a-3j) and phenythiopyridine acids (4a-4i) to form 1-azaxanthones (1a-1j) and 1-azathioxanthones (2a-2i), respectively, was efficiently promoted by Yb(OTf) 3 /TfOH as co-catalysts. And a number of substrates could be cyclized in moderate to good yields.