Search results for "Acene"
showing 10 items of 204 documents
Cytogenetic effects of promutagens in genetically engineered V79 Chinese hamster cells expressing cytochromes P450.
1993
Abstract V79 Chinese hamster cell lines genetically engineered to express rat CYP2B1, CYP1A1, CYP1A2, and their parental cell lines V79-MZ, without acetyltransferase, and V79-NH, with acetyltransferase, were studied for chromosome aberrations and sister chromatid exchange induced by aflatoxin B 1 , cyclophosphamide, benzo[a]pyrene, 7,12-dimethylbenz[a]anthracene and dimethylnitrosamine. The parental V79 cell lines did not show clastogenic effects. Significant clastogenic effects were observed after an 18 h exposure to aflatoxin B 1 and cyclophosphamide in CYP2B1 expressing cells, to benzo[a]pyrene in CYP1A1 and CYP1A2 expressing cells, to 7,12-dimethylbenz[a]anthracene and dimethylnitrosami…
Characterization of an epithelial, nearly diploid liver cell strain, from Chinese hamster, able to activate promutagens
1987
Epithelial liver cells of the Chinese hamster (CHEL cells) were propagated in culture for 35 passages. At favourable cell densities, the population doubling time in normal medium, was 20 h. L-Tyrosine amino transferase activity was retained at a measurable level, but its enhancement by dexamethasone was detected solely in cells of early passages. Pyruvate kinase was strongly activated by fructose-1,6-biphosphate at low substrate concentrations. These enzymatic properties suggest that the CHEL cells are derived from a sub-population of parenchymal hepatocytes or from cells closely related to parenchymal hepatocytes. With a lag period of a few hours, CHEL cultures metabolized benzo[a]pyrene. …
Dinuclear and tetranuclear complexes of copper coordinated by an anthracene-based new μ-bis(tridentate) ligand: Synthesis, structure, spectroscopy an…
2016
Abstract Copper(II) complexes of an anthracene-based new μ-bis(tridentate) ligand, N,N′-bis[anthracene-2-ylmethyl]-N,N′-bis[carboxymethyl]-1,3-diaminopropan-2-ol (H3acdp) with mixed donating groups, have been studied in solid state as well as in solution. The reaction of stoichiometric amounts of CuSO4·5H2O and the ligand H3acdp in the presence of NaOH at ambient temperature in methanol-dichloromethane, afforded a new dinuclear copper complex, [Cu2(acdp)(MeO)(MeOH)2] (1). On the other hand, the reaction of stoichiometric amounts of Cu(OAc)2·H2O and the ligand H3acdp in the presence of NaOH at ambient temperature in methanol-dichloromethane yielded, a novel tetranuclear copper complex, [Cu4(…
Palladium-Catalysed Amination of 1,8- and 1,5-Dichloroanthracenes and 1,8- and 1,5-Dichloroanthraquinones
2005
Diamino derivatives of anthracene and anthraquinone have been synthesised by palladium-catalysed coupling of 1,8-dichloroanthracene and 1,8-dichloroanthraquinone with a wide range of aliphatic and aromatic primary and secondary amines. The use of polyamines gave rise to a large number of new nitrogen- and oxygen-containing macrocycles incorporating anthracene or anthraquinone moieties. The method has also been employed for the preparation of bismacrocycles in which two cyclam or azacrown units are linked together by an anthracene bridge through C(sp2)−N bonds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Efficient two-step synthesis of face-to-face meso-substituted bis(corrole) dyads
2008
The synthesis of face-to-face meso-substituted bis(corrole) systems was revisited. By using a new synthetic pathway, the reaction was generalized to any type of linker and the yield was considerably increased. The dyads were obtained in yields up to 20 % from a dialdehyde linker and dipyrromethane in a one-step reaction. The best reaction conditions required a decreased amount of TFA catalyst (1.4 equiv.) and a large excess of dipyrromethane (up to 8 equiv). Under these conditions, four bis(corrole)s linked by 2,2′-diphenyl ether, 9,9-dimethylxanthene, anthracene, and dibenzofuran spacers were synthesized.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Development and validation of a procedure for estimating the hydrophobicity of structurally unrelated compounds by micellar liquid chromatography
1999
Reversed-phase liquid chromatography has been used most often to estimate values of log P, but despite years of study, there is no universally accepted method of performing these estimations. The main problem has to do with the fact that the hydrophobic parameter, log k w , depends on the hydrogen bond acceptor-donor character of the compounds. The use of micellar mobile phases to perform these estimations is evaluated here, and the influence of the nature of the surfactant (anionic, cationic, and nonionic) on the log k-log P relationships is studied. The use of a nonionic surfactant, such as Brij35, to prepare the mobile phases provided adequate results regardeless of the hydrogen bond acc…
Monoradicals and Diradicals of Dibenzofluoreno[3,2-b]fluorene Isomers: Mechanisms of Electronic Delocalization
2020
The preparation of a series of dibenzo- and tetrabenzo-fused fluoreno[3,2-b]fluorenes is disclosed, and the diradicaloid properties of these molecules are compared with those of a similar, previously reported series of anthracene-based diradicaloids. Insights on the diradical mode of delocalization tuning by constitutional isomerism of the external naphthalenes has been explored by means of the physical approach (dissection of the electronic properties in terms of electronic repulsion and transfer integral) of diradicals. This study has also been extended to the redox species of the two series of compounds and found that the radical cations have the same stabilization mode by delocalization…
Sequestering aromatic molecules with a spin-crossover Fe(II) microporous coordination polymer.
2012
All in a spin: A series of three-dimensional porous coordination polymer {Fe(dpe)[Pt(CN)(4)]}⋅G (dpe = 1,2-di(4-pyridyl)ethylene; G = phenazine, anthracene, or naphthalene) exhibiting spin crossover and host-guest functions is reported. The magnetic properties of the framework are very sensitive to the chemical nature (aromatic or hydroxilic solvents) and the size of the included guest molecules.
Highly selective fluorescence detection of hydrogen sulfide by using an anthracene-functionalized cyclam-CuII complex
2013
An anthracene-functionalised cyclam-copper(II) complex for the detection of HS- in aqueous environments has been prepared. This probe displays poor fluorescence but can selectively and sensitively detect HS- anions in water over other anions, biothiols and common oxidants such as H2O2 through remarkably enhanced emission. This turn-on response in the presence of the HS- anion is ascribed to a demetallation reaction that inhibits emission quenching observed in the initial complex as a result of the presence of the paramagnetic Cu2+ centre. Moreover, real-time fluorescence imaging measurements confirm that probe [Cu(1)](2+) can be easily used to detect intracellular HS- at micromolar concentr…
Supramolecular interactions of hexacyanocobaltate(III) with polyamine receptors containing a terminal anthracene sensor
2003
Abstract The fluorescence emission properties of a series of chemosensors containing a polyamine receptor bearing an anthracene signaling unit were studied. The fluorescence emission intensity is dependent on the protonation degree of the receptor, the fully protonated form exhibiting the highest emission intensity. By removing protons from the nitrogens a quenching effect can be observed, due to an electron-transfer from the amine to the excited fluorophore. The rate constant of the quenching process is exponentially dependent on the distance of the nitrogen from which the electron is transferred (β=0.6 A−1). The ability of the chemosensors for signaling anions was tested through the model…