Showing papers on "Fluorenone published in 1998"

One-Electron Reduction of Aromatic Ketones by Low-Valent Lanthanides. Isolation, Structural Characterization, and Reactivity of Lanthanide Ketyl Complexes

Abstract: In this paper we report on the isolation, structural characterization, and reactivity of a series of lanthanide ketyl complexes, which are generated by reactions of benzophenone and fluorenone with several different types of lanthanide reducing agents including Ln(OAr)2(L)x (Ar = C6H2-tBu2-2,6-Me-4; 1a: Ln = Sm, L = THF, x = 3; 1b: Ln = Yb, L = THF, x = 3; 1c: Ln = Sm, L = HMPA, x = 2; 1d: Ln = Yb, L = HMPA, x = 2), (C5Me5)2Ln(THF)2 (Ln = Sm, Yb), (C5Me5)Sm(OAr)(HMPA)2, Sm(N(SiMe3)2)2(THF)2, and Ln/HMPA (Ln = Sm, Yb) (HMPA = hexamethylphosphoric triamide). Reactions of 1a−d with 1 equiv of fluorenone in THF afforded the corresponding ketyl complexes Ln(OAr)2(ketyl)(L)2 (3a−d) in 85−90% isolated yields. Hydrolysis of 3a (Ln = Sm, L = THF) gave the corresponding pinacol-coupling product, 1,2-bis(biphenyl-2,2‘-diyl)ethane-1,2-diol (4), while air oxidation of 3a yielded fluorenone almost quantitatively. Reaction of 3a with 1 equiv of 1a followed by hydrolysis afforded fluorenol quantitatively. When 3a was dis...

Photophysical Properties of Intramolecular Charge-Transfer Excited Singlet State of Aminofluorenone Derivatives

Abstract: Photophysical properties of fluorenone and 12 aminofluorenone derivatives were investigated systematically by fluorescence quantum yield and picosecond lifetime measurements in cyclohexane, benzene...

Synthesis of Fluorenebisphenoxy Derivatives by Acid-sulfur Compound Catalyzed Condensation Reaction

Abstract: An efficient method for the synthesis of fluorenebisphenoxy derivatives from fluorenone and phenoxy compounds is successfully performed by the combined use of concentrated sulfuric acid as catalyst and 3-mercaptopropionic acid as co-catalyst. Several fluorenebisphenoxy derivatives are obtained in good yields by this one-step reaction.

Photochemical Pinacol Rearrangement

Abstract: Irradiation of 9,9‘-bifluorene-9,9‘-diol (1) gave 9-fluorenone and spiro[9H-fluorene-9,9‘(10‘-H)-phenanthren]-10‘-one (4), the latter arising from a pinacol rearrangement. The distribution of fluorenone and ketone 4 was solvent dependent with the latter being the major product in trifluoroethanol, a solvent known to stabilize carbocation intermediates. Laser flash photolysis of diol 1 in 2,2,2-trifluoroethanol or hexafluoro-2-propanol showed two transients absorbing at 350 and 505 nm with a weak band at 700 nm. The latter two peaks are assigned to the corresponding substituted 9-fluorenyl cation (5) formed from photoheterolysis of diol 1. Comparison of the decay kinetics between cation 5 and other 9-fluorenyl cations, the parent 9-fluorenyl and 9-phenyl-9-fluorenyl cations, showed that the decay of 5 was relatively insensitive to the nature of the solvent as compared to the latter two carbocations suggesting that unimolecular rearrangement in 5 competes with nucleophilic quenching.

Magnetic and electrochemical investigations on anions derived from oligoketones containing fluorenone and benzophenone units. An approach to the design of stable multiradical organic materials

Abstract: The mono- and poly-anions of some mono-, di- and tetra-ketones containing fluorenone and benzophenone moieties have been studied by NMR and cyclic voltammetry. Alkali metal anion radicals of fluorenone, generated by electron transfer from an alkali metal naphthalene radical anion exhibit markedly lower molar paramagnetic solvent shifts than those generated by direct reduction with an alkali metal. Evidence is provided for the involvement of hyperfine interactions between the naphthalene and the paramagnetic solute. The dianion of the diketone 9 is paramagnetic as are the dianions of the tetraketones 6 and 7. The NMR data, combined with those obtained by cyclic voltammetry, indicate that polyketones possessing fluorenone moieties connected through isophthaloyl ‘spacers’ are promising systems for the preparation of high-spin organics and electrophores.

Phosphorus-31 contact shifts as a measure of weak ligand affinities. interaction between alkali metal fluorenone radical anions and certain phosphorus (iii or v) ligands

Abstract: The nuclear magnetic resonance shifts, δobs, induced to 31P in Ph3P, (MeO)3P and (MeO)3PO by alkali metal fluorenone radical anions in tetrahydrofuran solutions were measured. These parameters, which depend significantly on the cation for a given ligand, and also on the ligand for a given cation, were used to extract the corresponding 31P contact shifts, δc(M). The latter parameters are proposed as a measure of the ligand affinity of a given phosphorus compound for a particular alkali metal. Trimethyl phosphate exhibits the greatest affinity for the lithium cation. The magnitudes of δc(M) imply some covalency between the cation and the radical anion and the ‘paradox’ of a heavier alkali metal such as potassium being covalently bonded to fluorenone radical anion has been explained. The transferability of the reported ligand affinities of Li+, Na+ and K+ is discussed. © John Wiley & Sons, Ltd.

Positive photoresist composition

Abstract: A chemical amplifying type positive photoresist composition, excellent in various properties, particularly in TDE resistance as well as sensitivity and resolution, and able to suppress unfavorable halation effect without deteriorating profile, which comprises (A) a resin which is converted to alkali-soluble from alkali-insoluble or only slightly alkali soluble by the action of an acid, (B) an acid generator, (C) a basic compound and (D) a fluorenone compound represented by the following formula (I): wherein R1, R2, R3, R4, R5, R6, R7 and R8 each independently represent hydrogen, alkyl having 1 to 6 carbon atoms which may be optionally substituted with halogen, halogen or nitro is provided; and a precise fine photoresist pattern can be formed in high precision using the photoresist composition.

Production of fluorene derivative

Abstract: PROBLEM TO BE SOLVED: To provide an economically excellent method for producing 9,9-bis(4-(2- hydroxyethoxy)phenyl)fluorene having an excellent product quality by a condensation through dehydration of fluorenone and phenoxyethanol without requiring the complex removing operation of a catalyst. SOLUTION: Fluorenone is reacted with phenoxyethanol in the presence of a catalyst obtained by ion-exchanging Mn+ present in the intercalation of montmorillonite represented by Mn+x/n(Al4-xMgx)Si8O20(OH)4.yH2O (M is a metallic atom or hydrogen atom; s satisfies the equation 0 =0)with one or more kinds of cations of elements selected from a group of aluminum, titanium, iron, tin, tungsten and copper to produce the objective 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene.

The absolute kinetics for radical addition and electronic energy transfer to (1.1.1)propellane

Abstract: Free radicals react more readily with [1.1.1]propellane, 1, than with styrene. For example Et3Si· reacts with 1 and styrene with rate constants of 6 × 108 M-1 s-1 and 2 × 108 M-1 s-1, respectively. Fluorenone, phenanthrene, triphenylene, benzophenone, and pyrene transfer electronic energy to 1 with rate constants well below the diffusion-controlled limit. For example, triplet benzophenone is quenched by 1 with a bimolecular rate constant of 9.9 × 106 M-1 s-1. A linear dependence of the log of the quenching rate constants, log kq, upon the excited-state energy of the donors is found.Key words: propellane, laser flash photolysis, free radicals, triplet states.

Oxidation catalyst and oxidation method using the same

Abstract: PROBLEM TO BE SOLVED: To obtain a target oxidized compound with a high rate of reaction conversion and selectivity by oxidizing effectively a substrate with molecular oxygen under mild conditions SOLUTION: Under the presence of an oxidation catalyst consisting of an imido compound such as N-(9-fluorenyloxi) phthalimide represented by the formula or an oxidation catalyst consisting of a cooperating oxidizing agent including the imido compound and a transition metal compound, substrate, such as a cyclic compound is oxidized by being brought into contact with molecular oxygen, eg fluorenone is obtained from fluorene with a high conversion selectivity in the formula R and R are identical or different, and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, and an acyl group, R and R may link with each other to form a double bond, or an aromatic or non-aromatic ring, R represents a ring group having tertiary carbon at the bonding site to an adjacent oxygen atom, and n represents an integer of 1-3

Novel Synthesis, Spectroscopic Studies and Rearrangement of 2-(Fluorenone)Benzothiazoline in the Presence of Metal Ions

Abstract: 2-(Fluorenone)benzothiazolinc [I] has been sylithesized by a literature method aud characterized hy several tecliniques (IR 1H NMR, 13C NMR, TG. DTA and UV-Vis.) and elemental analyses. The reactions of a solution of 2-(fluorenone)benzothiazoline with Pd(II). Hg(II). Cd(II), Zn(II) and UO2(VI) ious have been studied. Spectral studies showed that rearrangement of the benzothiazoline to the Schiff base, N-2-mercaptophenylenimine, has occurred. The IR and NMR spectra reveal that the azomethine nitrogen and the thiolate sulphur are coordinating sites. Electronic spectral data suggest a square-planar structure for the Pd(II) coinplex while the others have tetrahedral geometries. The thennal decomposition behaviour of the complexes has also been studied.

Solvation dynamics of the fluorenone radical anion by methanol: a direct MO dynamics study

Abstract: Solvation dynamics of the fluorenone radical anion by the methanol molecule have been studied by direct MO dynamics calculations. A cluster composed of the fluorenone radical anion and a methanol molecule, [Fl−…MeOH], was considered as a model of the solvation system. The Solvation process after vertical electron attachment to the neutral system, [Fl−…MeOH]unrelaxed → [Fl−…MeOH]relaxed, was treated by direct MO dynamics calculation. The absorption spectrum of the anionic system was monitored as a function of solvation time. The theoretical calculation shows that the potential energy is slightly decayed as a function of time due to the slight structural relaxation of Fl−, whereas the conspicuous spectral shift was not observed. This is due to the fact that the solvation structure of [Fl−…MeOH] resembles that of the neutral system. The solvation mechanism of the fluorenone radical anion is discussed and compared with that of the benzophenone radical anion.

Measurement of Dipole Moments and Lifetimes of Triplet States of Fluorenone and Its Derivatives by Time Resolved Microwave Dielectric Absorption.

Abstract: The technique of time resolved microwave dielectric absorption has been used to study the excited triplet states formed by the laser flash photolysis. The details of the experimental method and apparatus are discussed. The triplet state lifetimes and triplet state dipole moments of fluorenone and its derivatives are reported. The triplet state lifetime of fluorenone agrees with that obtained by optical absorption. The lifetime measurements with argon purging and with air equilibrated solution confirm the formation of triplet states. A marked increase in the triplet state dipole moment of fluorenone and its derivatives is observed and implies that their lowest triplet state is of (π, π * ) in nature.

Fluorenone derivative and electrophotographic photoreceptor using the same

Abstract: PROBLEM TO BE SOLVED: To obtain the subject new derivative comprising a specific fluorenone derivative having oxadiazole ring and bisazo group, having high sensitivity and good color-sensitive property, excellent in stability and durability and capable of withstanding repeated use and useful for electrophotographic photoreceptors, etc. SOLUTION: This new fluorenone derivative is represented by formula I (K and K are each a coupling residue containing hydroxyl group having a coupling ability) and has high sensitivity, good color-sensitive property and slight fatigue by light. Therefore, the fluorenone derivative hardly causes variation of sensitivity, antistatic property and residual electric potential when repeatedly used and has high stability and excellent durability and is useful for electrophotographic copying machines as well as photoreceptors for printers such as laser printer, liquid crystal and shutter printer. The compound is obtained by reacting 2-amino-9-fluorenone-7-carboxylic acid of formula II with hydrazium sulfate to afford a diamine of formula III, subjecting the diamine to tetrazotization according to ordinary method and coupling the resultant azo compound to the corresponding coupler.

1‐tert‐Butyl‐9‐methoxy‐4‐methyl‐1,2,3,4‐tetrahydro‐2‐azafluoren‐3‐one, a Novel Fluorenone

Abstract: The title compound, C 18 H 23 NO 2 , is the final compound in the reaction between an ethynyl Fischer carbene and a 2-azadiene. The reaction proceeds to the stereoselective formation of a 2-azafluorenone. The structure determination reveals hydrogen bonding linking the carbonyl O atom and the H atom attached to the N atoms of symmetry-related molecules. As a result, the structure packing is composed of dimers connected by two hydrogen bonds. These hydrogen bonds show a similar geometry to those found between pairs of bases in DNA, and the structure itself resembles some synthetic inhibitors of DNA transcription.

Composition for forming photoconductive layer of color display panel and fluorenone derivative for electron acceptor

Abstract: PROBLEM TO BE SOLVED: To provide a compsn. having superior thermal decomposability and capable of producing a color display panel less liable to a change in the luminance and color coordinates of the fluorescent screen by incorporating a specified styrene-acrylic copolymer as an org. binder, a specified fluorenone deriv. as an electron acceptor and a specified tetraphenylbutadiene deriv. as an electron donor. SOLUTION: This compsn. contains a styrene-acrylic copolymer represented by formula I as an org. binder, a fluorenone deriv. represented by formula II as an electron acceptor, a tetraphenylbutadiene deriv. represented by formula III as an electron donor and a solvent. In the formulae, each of R1 and R2 is H or alkyl, R3 is alkyl or alkylene, X is a polar group, (1) to (n) are variable so as to regulate the concn. of the photoconductive material and to regulate surface electric charges, R4 is carbonyl bonding to alkyl, alkoxy, etc., R5 is H, halogen or a functional group such as alkyl, R6 is diethylamino or methoxy and R7 is H, methoxy, etc.

Rectifying and Photovoltaic Effects of Organic Hetero-Junction Films Based on Fluorenone Derivatives/Poly (3-Methylthiophene) Prepared by Electrochemical Polymerization and Undoping

Abstract: The eletrooxidative polymerization of 3-methylthiophene is a convenient method to synthesize an electroconducting polymer poly(3-methylthiophene) (PMeT) in form of a thin solid film incorporated by the counter anion from the supporting electrolytes as a dopant. Electropolymerized PMeT is konwn to be very stable toward oxygen, moisture and temperature in both their doped and undoped state. The thickness of these films, the amount of dopant and the properties of the films can be easily controlled electrochemically[1]. We have proposed dry organic hetero-junction devices based on electron transfer reaction between an organic dye molecule and PMeT [2]. Wet devices based on electron transfer reaction have been already accomplished by many reseachers, but these devices have complex structure. Our dry device is very simple. We expect that these devices should not behave like a conventional semiconductor device base on band theory and that they might be a next coming origanic molecular devices.

Structures of Dibenzocycloheptenylidene- and Fluorenylidene-(2,4,6-tri-t-butylphenyl)phosphines and Their Reactions with Sulfur.

Abstract: Dibenzocycloheptenylidene(2,4,6-tri-t-butylphenyl)-phosphine and fluorenylidene(2,4,6-tri-t-butylphenyl)-phosphine were prepared by the reactions of lithium silylphosphide with benzosuberenone and fluorenone, respectively. The reactions of the phosphines with sulfur were carried out to compare the results with those of the corresponding diphenyl derivative, and the new findings are discussed in terms of steric hindrance based on the results of the X-ray crystallographic analyses for dibenzocycloheptenylidenephosphine and its sulfide and the computational structure for the fluorenyl derivative. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8: 375–382, 1997