Showing papers on "Fluorenone published in 1993"

Substituent, solvent, and temperature effects on radiative and nonradiative processes of singlet excited fluorenone derivatives

Abstract: Fluorescence lifetimes, fluorescence quantum yields, and triplet yields have been measured for 2-fluorofluorenone and 2-methoxyfluorenone in different solvents having a widerange of polarities. The photophysical characteristics of the fluoro derivative were found to be similar to those of fluorenone itself. The dominating process in nonpolar and moderately polar solvents is singlet-triplet transition with temperature-independent and additional temperature-dependent components. However, the photophysics of the methoxy derivative is governed by internal conversion to the ground state, which gains in importance with increasing solvent polarity and shows a temperature-dependent rate in nonpolar solvent

Process for the preparation of bishydroxy aromatic compounds

Abstract: A process for the preparation of bishydroxy aromatic compounds, such as 9,9-bis(4-hydroxyphenyl)fluorene, involving contacting a ketone, such as fluorenone, with phenol or substituted phenol in the presence of a mercaptan cocatalyst and a solid superacid catalyst of Hammett acid strength H0 greater than about -13.0. Solid superacid catalysts include the sulfates, sulfated oxides, sulfated oxyhydroxides, and sulfated oxysilicates of aluminum, tin, and the Group IVA metals, such as zirconium, as well as mixed metal oxides, such as tungsten-zirconium oxides. Isolated yields are high for 9,9-bis(4-hydroxyphenyl)fluorene.

Production of fluorenone

Abstract: PURPOSE:To improve the production process for fluorenone by oxidizing fluorene dispersed in a mixture of agueous sodium hydroxide and an organic solvent immiscible with water with molecular oxygen in the presence of a quaternary ammonium salt. CONSTITUTION:An organic solvent having 80 to 150 deg.C standard boiling point such as toluene is used to effect oxidation reaction at a temperature lower than 100 deg.C so that the water vaporized during the oxidation reaction is accompanied by the exhaust gas after and removed out of the reactor. The oxidation reaction is accelerated and the reaction mixture can reeadily be separated into the oil phase and the aqueous phase and the recovered sodium hydroxide solution can be reused without concentration and the consumption of the catalyst can be saved. The product can readily be separated from the solvent by single distillation.

Fluorene compound and electrophotographic photoreceptor using the same

Abstract: PURPOSE:To obtain a new fluorene compound capable of giving electrophotographic photoreceptors of high sensitivity with excellent durability when used as charge transport substance. CONSTITUTION:A fluorene compound of formula 1 (R1 is a substituted or nonsubstituted aromatic or heterocyclic group or an alkoxycarbonyl; (x) and (y) are each 0-4 and totaling of them is 1-4) or formula 2 (R2 is an alkyl), e.g. 2,4,7-trinitro-9-fluorenidene(2-methylphenylacetonitrile). The compound of formula 1 or 2 can be obtained by reaction of a fluorenone compound of formula 3 with an acetonitrile derivative of formula 4 or a malonic acid derivative of formula 5. The compound of formula 1 or 2 can be used not only for electrophotographic photoreceptors but also preferably used in the electronic industry for electronic devices such as solar cells and organic EL elements.

Structure of the charge-transfer complexes 2,4,5,7-tetranitro-9-fluorenone–1-ethylnaphthalene (1/1) (I) and 2,4,5,7-tetranitro-9-fluorenone–3,6-dimethylphenanthrene (1/1) (II)

Abstract: In each structure the asymmetric unit consists of two molecules whose parallel rings are at van der Waals distances and stack, alternately, along the a axis for (I) and along the n-glide direction for (II). The carbon-skeleton geometry of the fluorenone within both charge-transfer complexes is not significantly altered from that of the parent 2,4,5,7-tetranitro-9-fluorenone

Spectroscopic, Voltammetric and Coordination Studies on Novel Schiff Base Ligand Derived from Fluorenone with Phenyl Thiosemicarbazide. III

Abstract: Some new transition metal complexes of the Schiff base ligand (FPTH) formed by condensation of fluorenone with 4-phenylthiosemicarbazide were prepared. Isolation of the solid metal (II) complexes depends on the metal salt used, pH and the reaction conditions. Characterization of these complexes has been made by elemental analyses, molar conductivities, NMR (1H, 13C), magnetic susceptibility, vissible studies and IR spectra. From EPR studies; symmetry and bonding character for paramagnetic copper(II) complex were determined. The polarographic and cyclic voltammetric curves of the Schiff base (FPTH) were recorded in Britton-Robinson buffer series of pH 3–10. The DC polarograms and the cyclic voltammograms exhibited a single 4-electron irreversible diffusion-controled reduction step represented the saturation of C=N and C=S electroactive centers. The corrosion inhibition of aluminium in HCl using FPTH is studied. The antimicrobial activity of ligand and its metal complexes has also been demonstrated.

Direct Measurement of Collisional Energy Transfer Between Highly Vibrationally Excited Triplet Fluorenone and Bath Gases

Abstract: Intensities and decay rates of CO2-laser induced delayed fluorescence are used to probe collisional relaxation of vibrationally excited fluorenone diluted with bath gases: He, N2, Kr. The average energies 〈ΔE〉 transferred per collision are found to vary with vibrational energy, the energy dependences of the collisional efficiency eventually level off.

Production of fluorene derivative and its purification

Abstract: PURPOSE:To efficiently produce a fluorene derivative in a high yield and in a short time without wastefully using fluorenone by a profitable method CONSTITUTION:Fluorenone is reacted with phenoxyethanol in the presence of sulfuric acid and a thiol compound, and the reaction solution is dissolved in a lower aliphatic alcohol and subsequently mixed with water to deposit 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene [fluorene derivative] The fluorene derivative is recrystallized in a lower aliphatic alcohol as the solvent to obtain the objective highly pure fluorene derivative

Substituent, Solvent, and Temperature Effects on Radiative and Nonradiative Processes of Singlet Excited Fluorenone Derivatives

Abstract: Fluorescence lifetimes, fluorescence quantum yields, and triplet yields have been measured for 2-fluorofluorenone and 2-methoxyfluorenone in different solvents having a widerange of polarities. The photophysical characteristics of the fluoro derivative were found to be similar to those of fluorenone itself. The dominating process in nonpolar and moderately polar solvents is singlet-triplet transition with temperature-independent and additional temperature-dependent components. However, the photophysics of the methoxy derivative is governed by internal conversion to the ground state, which gains in importance with increasing solvent polarity and shows a temperature-dependent rate in nonpolar solvent

[Effect of structural features of nitro-derivatives of fluorenone and biphenyl on frameshift mutagenesis in tester strains of Salmonella typhimurium].

Abstract: Comparative mutagenic activity of 7 derivatives of biphenyl and fluorenone, 4,4'-dinitrobiphenyl-2,2'-dicarboxylic acid; 4,4',6,6'-tetranitrobiphenyl-2,2'-dicarboxylamide; 2-nitrofluorenone-5-carboxylic acid; 2,7-dinitrofluorenone-5-carboxylic acid; 2,7-dinitrofluorenone-5-carboxylamide; 2-nitrofluorenone-5,7-dicarboxylic acid; 2,4-dinitrofluorenone-5,7-dicarboxylic acid was studied. The highest activity was demonstrated for 2,7-DNF-5-KA and 2,7-DNF-5,7-DK which induced frameshift mutations in the tester strains Salmonella typhimurium TA1537, TA97, TA1538, TA98. High mutagenicity of these compounds is correlated with the position of nitro-groups and the effects of carboxylic and carboxyamide groups.