We report that an enhancement in electrical bistability in devices based on organic molecules can be achieved by the introduction of semiconducting nanoparticles. Here, devices based on alternate layers of a dye in the xanthene class and CdSe nanoparticles have been compared with devices based on the individual components. Results from dye/CdSe devices have yielded an appreciable enhancement in...

Oxidative stress is directly related to several diseases and symptoms, where antioxidant compounds, such as xanthenes, may become important in prevention and/or treatmant. Ten biologically active 9-aryl substituted 2,6,7-trihydroxyxanthen-3-one derivatives were synthesized using reliable one-pot synthesis and their structures were confirmed by IR, 1H and 13C NMR spectroscopy and mass spectromet...

In the title compound, C(31)H(25)ClO(3), the central ring of the xanthene core shows a shallow boat conformation, while the outer six-membered rings display envelope conformations. The dihedral angle between the outer aromatic rings is 88.1 (3)° and the dihedral angles between the chloro-benzene ring and the two phenyl rings are 69.5 (2) and 69.6 (2)°.

In the title compound, C(18)H(16)O(4), a monoprenylated xanthone, the xanthone skeleton exhibits an essentially planar conformation (r.m.s. deviation 0.0072 Å) and the isoprenyl side chain remains approximately in the mean plane of the xanthone unit, making a dihedral angle of 4.5 (2)°. The hydroxyl group forms an intra-molecular O-H⋯O hydrogen bond. Moreover, there is a weak inter-molecular C-...

In the title compound, C(27)H(26)O(4), each of the cyclo-hexenone rings adopts a half-chair conformation. The dihedral angle between the two phenyl rings is 89.53 (5)°. The hy-droxy and carbonyl O atoms face each other and are orientated to allow the formation of two intra-molecular O-H⋯O hydrogen bonds, which are typical of xanthene derivatives.

In the title compound, C(33)H(38)N(4)O(3), the mean planes of the 9H-xanthene unit and spiro-lactam (nine-atom) core are almost mutually perpendicular at 87.26 (6)°. Intra-molecular N-H⋯O and C-H⋯N inter-actions influence the 4-oxo-pent-2-en-2-yl-amino conformation. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into chains along [001].

Fluorogenic molecules are important tools for advanced biochemical and biological experiments. The extant collection of fluorogenic probes is incomplete, however, leaving regions of the electromagnetic spectrum unutilized. Here, we synthesize green-excited fluorescent and fluorogenic analogues of the classic fluorescein and rhodamine 110 fluorophores by replacement of the xanthene oxygen with a...