Showing papers on "Fluorenone published in 2001"

Spectroscopic Studies of Fluorenone Derivatives

Abstract: The absorption and steady-state fluorescence spectra of fluorenone, 1-hydroxyfluorenone, and 3-dimethylaminofluorenone have been obtained for various concentrations in a series of non-polar and polar solvents. The substituents (-OH and -N(CH3)2) as the electron-donating functional groups cause a large shift of the longwave absorption band and Stokes' shift of the monomer- and excimer-fluorescence bands in comparison with fluorenone. The total emission spectrum of 3-dimethylaminoflourenone in polar aprotic solvents exhibits a new band at λ ≃ 500 nm originating form the emission of the twisted intramolecular charge transfer (TICT) isomer. The excited state dipole moments of the emiting species of the molecule studied are determined using the solvatation shift method and calculated values of the ground state dipole moments.

(9H-fluoren-9-ylidene)fluoromethyllithium, a stabilized fluoroalkenyl carbanion. Preparation, reactions, 13C and 19F NMR spectra

Abstract: (9 H -Fluoren-9-ylidene)fluoromethyllithium ( 1 ) was prepared by a low-temperature transmetallation of bromo(9 H -fluoren-9-ylidene)fluoromethane ( 2 ). Whereas the synthesis of unlabeled bromofluoroalkene 2a was based on Wittig-Horner reaction of fluorenone ( 3 ) with ethyl (diethoxyphosphoryl)fluoroacetate ( 4 ), (1- 13 C)-labeled compound 2b was obtained via an addition of labeled lithium 1-ethoxy-2-fluoro(2- 13 C)ethen-1-olate ( 5 ) to ketone 3 . Fluoroethenyllithium 1 was found by a low-temperature 19 F NMR spectroscopy to be stable up to -40 °C; it was reacted with the series of electrophiles, e.g. benzaldehyde ( 6 ), methyl iodide ( 7 ) or chloro(trimethyl)silane ( 8 ). 13 C NMR experiments with (1- 13 C)-labeled 1a proved that fluorocarbenoid 1 is probably monomeric in THF solution in analogy to other halocarbenoids.

Bis(hydroxyphenylthio)fluorene compound and method for producing the same

Abstract: PROBLEM TO BE SOLVED: To obtain a new fluorene compound having excellent performances as a heat-resistant and high-refractive index material and to provide a method for producing the fluorene compound. SOLUTION: This bis(hydroxyphenylthio)fluorene compound is characterized in that the fluorene compound is represented by the general formula (I) [wherein, R 1 to R 4 are each the same or different and denote each hydrogen atom or a 1-6C linear or branched alkyl group; and n denotes an integer of 0-10]. The method for producing the compound represented by the general formula (I) is characterized by reacting (1) fluorenone with (2) mercaptophenols. COPYRIGHT: (C)2002,JPO

Oxidative carbonylation of aromatic hydrocarbons in the system containing Pd or Rh compound, trifluoroacetic acid and its anhydride, and MnO2 or Mn2O3

Abstract: Manganese(II) and manganese(IV) oxides are effective oxidants for the reaction of oxidative carbonylation of aromatic hydrocarbons proceeding at 0.1-1.5 MPa of CO and 20-100°C in trifluoroacetic acid and its anhydride and catalysed by Pd and Rh compounds. Under these conditions up to 9000 moles of aromatic acid is formed per 1 g-at of platinum. With rhodium catalyst instead of the palladium in the case of toluene content of p-toluic acid in the target product increases from 50 to 90%. Carbonylation of biphenyl at 0.1 MPa of CO and 20°C leads toformation of about 15% of fluorenone together with 4-phenylbenzoic acid (60%).

Dibenzopyran-6-one derivative and liquid crystal composition containing the same

Abstract: PROBLEM TO BE SOLVED: To obtain the subject new compound having a large minus dielectric anisotropy and a large tilt angle, and useful as a constituent component of a ferroelectric liquid crystal suitable for a display element utilizing τ-Vmin. SOLUTION: This new compound is the one of compounds represented by the formula (R1 and R2 are each a 2-16C alkyl, or the like; X and Y are each O or CO with the proviso that X and Y are not samel; Z is a single bond, O-CH2, or the like; P is a single bond, 1,4-phenylene, or the like), e.g. 3,8- dinonyloxy-6H-dibenzo[b,d]pyran-6-one. A synthetic method of the compound of the formula comprises carrying out Friedel-Crafts' reaction of fluorene with an alkanoyl chloride, subjecting the product to hydrazine reduction, oxidizing the obtained compound with oxygen in a solvent in the presence of a base to convert the compound into a fluorenone derivative, and oxidizing the product with a peroxide to provide the compound of the formula.

Characterization of bisazo compounds employing ultrafast spectroscopy

Abstract: Fluorenone-based bisazo compounds with different substituents have been investigated in various organic solvents and in a solid state by means of absorption, fluorescence and picosecond time-resolved absorption pump–probe spectroscopy. The bisazo compounds were found to coexist in azo–enol and hydrazone–quinone (HQ) tautomeric forms. Absorption spectra of the two forms were determined and excited-state properties were characterized. The azo–enol tautomeric form has a short, of tens of ps, excited-state lifetime and shows strong excited-state absorption, whereas stimulated emission is weak or absent. The HQ tautomeric form has a longer excited-state lifetime and shows sizeable stimulated emission. The main spectroscopic features of bisazo molecules in a solid state are similar to those in solutions, however, the excited-state relaxation is influenced by the specific solid phase effects. The lifetimes of the HQ form molecules in solutions differ by more than 10 times for bisazo compounds with different substituents and correlate with the photosensitivity of xerographic layers based on these compounds.

Polymer and production of polymer

Abstract: PROBLEM TO BE SOLVED: To obtain a polymer which can express excellent thermal stability, electric insulation, and mechanical strengths, is suitable for ink printer heads, can form optical patterns and can be subjected to a cross-linking reaction or a chain-extending reaction, by reacting a specific polymer precursor with a borane. SOLUTION: A polymer of formula I [A is a group of formula II (R is H, an alkyl, an aryl or the like) or the like; B is a group of formula III or the like; (n) is an integer expressing the number of repeating monomer units]. The polymer can be obtained by synthesizing a precursor polymer of formula IV (A is CO) and then reacting the precursor polymer with a borane. For example, a polymer is obtained by reacting 4,4'-difluorobenzophenone with 9,9-bis(4- hydroxyphenyl)fluorenone under heating and stirring, and then reacting the obtained polymer of formula V [(n) is about 130] with a borane-tetrahydrofuran complex.

New polymer emitting blue light as light-emitting display device

Abstract: PURPOSE: Provided is a new polymer emitting blue light as light-emitting display device, which is fluorenene based derivative by performing a methylene of fluorenone based derivative having steric hindrance. CONSTITUTION: A preparation method of co-polymer emitting blue light comprises the following steps: (i) performing methylenation of 9-fluorenone of formula 1 and derivative thereof by using Tebbe to 9-fluorenene of formula 2 and derivative thereof; (ii) obtaining a living co-polymer whose mole number and molecular weight of fluorene based unit are controlled by co-polymerizing the 9-fluorenene and derivative thereof with vinyl based monomer through using alkyl lithium and alkali metal naphthalenide initiator in the presence of polar or non-polar solvent; (iii) obtaining a block co-polymer by co-polymerizing the living co-polymer obtained in step (ii) with monomer for manufacturing polymer electrolyte, R2 is H, F, Cl, N(CH3)2, OSi(CH3)2(t-Bu), R3 is H or Cl, R2 and R3 are not always same, R4 and R5 are H, F, N(CH3)2, OH or NH2 independently.