a simple and environmentally benign procedure for the synthesis of 14-aryl-14h-dibenzo[a,j]xanthenes by a one-pot condensation of 2-naphthol with aromatic aldehyde in the presence of [et3nh][hso4] as an acidic ionic liquid catalyst under solvent-free conditions has been developed. the reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused s...

14-aryl- and 14-alkyl-14-h-dibenzo [a,j]xanthenes are prepared from the reaction of aromatic- and aliphaticaldehydes with β-naphthol in the presence of catalytic amounts of 4-dodecylbenzenesulfonic acid(dbsa) as asurfactant-type brønsted acid catalyst in toluene and under solvent-free conditions in excellent yields and shortreaction times. the catalyst was recovered and reused for five successi...

A new spirocyclized rhodol-based fluorescent probe has been developed for detecting mitochondrial Cu(+). Alkylation of the hydroxy group of a xanthene moiety with a tris(2-pyridylmethyl)amine-based ligand induced the formation of a non-fluorescent spirocyclic structure. The reaction with Cu(+) in the presence of submillimolar concentrations of glutathione at physiological pH resulted in the eli...

After oneand two-colour ps-excitation the transient absorption of rose bengal, erythrosin B and eosin Y in the spectral range from 450 to 670 nm was probed using picosecond continuum pulses generated in H2O—D 2 O mixture. Our experiments showed for all dyes a high T1—Tn absorption signal above 590 nm where no ground state absorption occurs. These excited triplet states can be effectively popula...

The title compound, C(31)H(20)N(2)O(5)·C(2)H(3)N, was synthesized by the reaction of fluorescein hydrazide and excess 2-hydr-oxy-1-naphthaldehyde in acetonitrile. The spirolactam ring is planar and is nearly at right angles to the two benzene rings of the xanthene system. The dihedral angle between the two benzene rings of the xanthene system is 9.92 (4)°. In the crystal structure, the mol-ecul...

We present a computational study on the electrical bistability behavior of four xanthene derivatives based on sodium fluorescein. Intra- and intermolecular charge transfer parameters are computed and employed to rationalize the efficiencies experimentally determined for resistive memory devices based on these organic materials. Charge injection at the electrode/organic interface in the presence...

A xanthene-forming condensation reaction yields rhodol and rhodamine dyes carrying a zinc-binding ligand that includes the aniline-type nitrogen donor of the fluorophores. Upon zinc coordination in neutral aqueous solution, rhodol RF3 behaves as a ratiometric sensor, and rhodamine RA1 acts as a turn-off intensity-based indicator. Both fluorescent compounds bind the divalent zinc cation with mic...

Erythrosine (ErB) is a xanthene and an US Food and Drug Administration approved dye used in foods, drugs and cosmetics. Although its utilization is permitted, ErB is described as inhibitor of enzymes and protein-protein interactions and is toxic to pituitary and spermatogenesis processes. However, the genotoxicity and mutagenicity of ErB is inconclusive in the literature. This study aimed to an...