Showing papers on "Fluorenone published in 1995"

Ruthenium catalyzed regioselective copolymerization of anthrone, fluorenone, or xanthone with α,ω-dienes

Abstract: This paper reports a novel ruthenium catalyzed regioselective copolymerization reaction between anthrone, fluorenone or xanthone and α,ω-dienes such as 1,3-divinyltetramethyldisiloxane and 3,3,6,6-tetramethyl-3,6-disila-1,7-octadiene. This reaction involves the ruthenium catalyzed regioselective Anti-Markovnikov insertion of the carbon-carbon double bonds of the α,ω-dienes into the aromatic carbon-hydrogen bonds which are ortho to the carbonyl group of anthrone, fluorenone or xanthone. Similar ruthenium catalyzed copolymerization reactions between acetophenone and α,ω-dienes [1] have been recently reported as have reactions between acetophenone and alkenes to yield monomeric ortho-alkyl substituted acetophenones [2].

Zur darstellung p-1-adamantyl-substituierter phosphaalkene

Abstract: 1-Adamantylphosphine 1 did not react with fluorenone in the presence of BF3-etherate to give the desired phosphaalkene. Instead, addition of 1 at the C[dbnd]O-bond and complexation of BF3 by the lone pair at phosphorus with formation of the co-ordinated α-hydroxyphosphine 2 took place. The P-I-adamantyl-substituted phosphaalkene 1-AdP[dbnd]C(OSiMe3)'Bu 6 was synthesized in the reaction of equimolar quantities of 1-adamantyl-bis-trimethylsilylphosphine 4 and pivaloyl chloride. In the reaction mixture, the E/Z-isomers E-6 and Z-6 were observed by 31P-NMR-spectroscopy. Prolonged heating of the reaction mixture at 40°C led to isomerisation, giving exclusively the E-isomer E-6.

Intramolecular deactivation of photoexcited anthracenes by aromatic ketones

Abstract: The excited state properties of anthracenes non-conjugatively linked to various types of aromatic ketone were investigated in non-polar solution by determination of the quantum yields of fluorescence and intersystem crossing. In a series of substituted bichromophoric ω-(9-anthryl)propiophenones, the degree of intramolecular fluorescence quenching by the ketone was found to be associated with an increase in the quantum yield of anthracene triplet state formation. Excitation of 4′-piperazinoacetophenone tethered to anthracene resulted in deactivation within the acetophenone chromophore, rather than singlet energy transfer to anthracene. For photoexcited anthracene linked to 2-amido-substituted fluorenone, intramolecular exothermic transfer of the singlet excitation energy to the fluorenone chromophore was found to proceed with high efficiency.

Fluorenone derivative and laminated electrophotographic receptor using the derivative

Abstract: PURPOSE:To obtain a new fluorenone derivative useful for electrophotographic receptor having high charge potential and charge-retainability and exhibiting high sensitivity, low residual voltage and excellent repeated electrophotographic characteristics. CONSTITUTION:This compound is expressed by formula I [R is a (halogenated) alkyl or an alkoxy; R1 to R4 each is H, a (halogenated)alkyl or an alkoxy], e.g. N-(2,4,5,7-tetranitrofluorenylidene)-2,5-di-t-butylaniline. The compound of formula I can be produced by reacting 2,4,5,7-tetranitrofluorenone with a compound of formula II.

Stoichiometry and mechanism of protonation of alkali metal salts of benzophenone radical anions by weak proton donors and its relevance to the base-catalyzed decomposition of benzopinacol

Abstract: The Stoichiometry of the protonation of lithium and potassium salts of benzophenone radical anions and of the lithium salt of the fluorenone radical anion by methanol has been measured and found to be [(Ar2C=O)−]/[MeOH] =2∶1. This result, which was obtained by the method of magnetic titration, implies that paramagnetism decays by the reaction between a ketyl anion and a ketyl radical (i.e., a protonated ketyl anion). The reactivities of alkali metal salts of fluorenone radical anions in relation to methanol exhibit a pronounced dependence on the nature of the counterion. No kinetic deuterium isotope effect has been found for the protonation of the lithium salt of the benzophenone radical anion in tetrahydrofuran (THF) bytert-pentyl alcohol. The lithium salt of the benzophenone radical anion inN,N,N′,N′-tetramethylethylenediamine (TMEDA) behaves markedly differently. Namely, its protonation by methanol exhibits 1 ∶ 1 Stoichiometry and it reacts considerably more slowly withsec-butyl alkohol,K(THF)/K(TMEDA) = 2.5. Benzopinacol undergoes decomposition by an alkoxide base to diphenyl ketyl, which decays into an equimolar mixture of benzophenone and benzhydrol. The reaction follows second-order kinetics and the specific rate constants exhibit an inverse relationship with respect to the initial concentration of the alkoxide. With a very strong base benzopinacol decomposes into two diphenyl ketyl anions. On the basis of this information as well as on studies of products, relevant mechanisms are proposed for the protonation of ketyl anions and for the decomposition of aromatic pinacols in basic media.

Thermal decomposition kinetics and mechanism of Cu(II), Zn(II) and Cd(II) complexes derived from fluorenone anthranilic acid

Abstract: Copper(II), zinc(II) and cadmium(II) complexes of the Schiff base, fluorenone anthranilic acid were prepared and characterized by elemental analysis, magnetic measurements, conductivity experiments and electronic and infrared spectral studies The thermal decomposition kinetics and mechanism of these chelates was studied from TG data

Process for the production of fluorenebisphenol

Abstract: Prepn. of 9,9-bis(4-hydroxyphenyl)fluorene (I) by a beta -mercaptopropionic acid or mercaptoacetic acid catalysed condensn. of fluorenone with phenol in a strongly acidic medium, comprises two stages; (a) a condensn. reaction at 55-65 degrees C. and (b) an isomerisation reaction at 75-100 degrees C..