Showing papers on "Fluorenone published in 2010"

Fluorescence quenching phenomena facilitated by excited-state hydrogen bond strengthening for fluorenone derivatives in alcohols

Abstract: Spectroscopic studies on benzo[b]fluorenone (BF) solvatochromism in several aprotic and alcoholic solvents have been performed to investigate the fluorescence quenching by hydrogen bonding and proposed a weaker ability to form intermolecular hydrogen bond of BF than fluorenone (FN). In this work, the time-dependent density functional theory (TD-DFT) method was used to study the excited-state hydrogen bonding of both FN and BF in ethanol (EtOH) solvent. As a result, it is demonstrated by our theoretical calculations that the hydrogen bond of BF-EtOH complex is almost identical with that of FN-EtOH. Moreover, the fluorescence quantum yields of FN and BF in the alcoholic solvent is efficiently dependent on the energy gap between the lowest excited singlet state (fluorescent state) and ground state, which can be used to explain the fluorescence quenching by the excited-state hydrogen bond strengthening. (C) 2009 Elsevier B.V. All rights reserved.

Interactions, Behavior, And Stability of Fluorenone inside Zeolite Nanochannels

Abstract: The development of functional materials based on the supramolecular organization of photoactive species in nanosized porous matrices requires a deep knowledge of host−guest interactions and of their influence on material properties and stability. Extensive first-principles investigations on the fluorescent dye fluorenone inside zeolite L, both at dry conditions and in the presence of water, have unraveled the molecular origin of the peculiar stability of this composite in humid environments, a fundamental prerequisite for practical applications. Results of first-principles molecular dynamics simulations, structural optimizations, and TDDFT calculations, validated by comparison with experimental data, provide a comprehensive picture of the structure, energetics, electronic excitation properties, and room-temperature behavior of the fluorenone/zeolite L composite and predict a substantial optical anisotropy for this material also maintained upon contact with water. The interaction of the fluorenone carbonyl...

Method for producing fluorene derivative

Abstract: A method for producing a fluorene derivative by reacting fluorenone with a phenol or a phenoxyalcohol in the presence of an acid catalyst includes: adding an alkali to an obtained reaction liquid containing a fluorene derivative; and concentrating a resultant mixture liquid without removing the alkali thus added and a reaction product of the alkali, thereby separating an unreacted phenol or unreacted phenoxyalcohol.

Facile C-H alkylation in water: enabling defect-free materials for optoelectronic devices.

Abstract: A facile method for the alkylation of fluorene achieved via direct C−H alkylation under aqueous conditions is reported, wherein the formation of fluorenone is inhibited, resulting in the exclusive formation of the desired dialkyl-substituted fluorene monomer. As a proof of concept, this method has also been successfully extended to perform N-alkylation of carbazole, diphenylamine, and N,N-dialkylation of aniline in high yields.

Comparing Spin‐Selective Charge Transport through Donor–Bridge–Acceptor Molecules with Different Oligomeric Aromatic Bridges

Abstract: Burning bridges: The exponential distance dependence (β value) of singlet and triplet charge recombination (CR) pathways is determined for three donor-bridge-acceptor (DBA) molecules. p-Phenylethynylene and fluorenone bridges have similar β values, which differ significantly from those of p-phenylene bridges, thus implying that β for both singlet and triplet CR is system-dependent, not bridge-specific.

Rational design, synthesis, biophysical and antiproliferative evaluation of fluorenone derivatives with DNA G-quadruplex binding properties.

Abstract: Molecular modeling studies carried out with experimental DNA models with the sequence d[AG3(T2AG3)3] suggest that the introduction of a net positive charge onto the side chain of a series of fluorenone carboxamides can improve G-quadruplex binding. The terminal morpholino moiety was replaced with a novel N-methylmorpholinium cation starting from two 4-carboxamide compounds. A different substitution on the fluorenone ring was also investigated and submitted to the same quaternarization process. All compounds were analyzed for their DNA binding properties by competition dialysis methods. In vitro antiproliferative tests were carried out against two different tumor cell lines. Docking experiments were conducted by including all four known human repeat unit G-quadruplex DNA sequences (27 experimentally determined conformations) against the most active fluorenone derivatives. The results of theoretical, biophysical, and in vitro experiments indicate two novel derivatives as lead compounds for the development of a new generation of G-quadruplex ligands with greater potency and selectivity.

Synthesis and characterisation of fluorenone–thiophene-based donor–acceptor oligomers: role of moiety sequence upon packing and electronic properties

Abstract: A series of oligomers constituting alternating thiophene and fluorenone residues, designed to evaluate the effect upon both electronic properties and packing of the moiety sequence in the light of donor–acceptor concept, were synthesised and studied by cyclic voltammetry, optical spectroscopy, and XRD investigations into crystals, films, and powders. Moreover, ab initio calculations, based on Density Functional Theory, were carried out on selected molecules. A clear indication of close-packing induction by fluorenone in the oligomers, together with the factors determining the electrical and optical properties, are derived and presented. In the light of the performance of selected compounds in prototypes of p-type FET devices and bulk heterojunction solar cells, some general indications of chemical structure requirements for applications such as photovoltaic cells are described.

Electrochemical tuning of the optoelectronic properties of a fluorene-based conjugated polymer.

Abstract: The electrochemical reduction of a fluorene-based conjugated polymer, poly(9-fluorenone-alt-9,9-dioctylfluorene), was investigated for the first time. The carbonyl group in the fluorenone unit was selectively and quantitatively converted to the methylene group, as determined by 1H NMR, IR, and energy-dispersive X-ray (EDX) analysis. The optical and electrochemical properties of the polymers were studied by UV−vis, photoluminescence (PL), and cyclic voltammetry (CV) measurements and were found to be tunable by varying the reduction level.

Tunable electronic structures and optical properties of fluorenone-based molecular materials by heteroatoms.

Abstract: The ground-state and excited-state electronic structures as well as the tunable optical properties of a variety of newly designed fluorenone-based molecular materials have been theoretically investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The substitutes on the O atom in the carbonyl group of the fluorenone (FN) molecule with S (FN—C═S), Se (FN—C═Se), and Te (FN—C═Te) atoms can significantly influence their electronic structures, molecular orbitals, geometric conformations, and optical properties of fluorenone-based molecular materials. Due to the important difference of electronegativity for O, S, Se, and Te atoms in the same group, the ground-state dipole moment of these fluorenone-based molecular materials is gradually decreased in the order FN, FN—C═S, FN—C═Se, and FN—C═Te. At the same time, the ground-state bond length of the C═X (X refers O, S, Se, and Te) is gradually increased in the order of FN, FN—C═S, FN—C═Se, and FN—C═Te. Due to ...

Insights into the Effect of the Ketylimine Group on the Fluorescence Deactivation of Oligofluorenes

Abstract: A series of oligofluorenes containing arylketylimines in the 9-position ranging between 1 and 3 fluorene segments was prepared. The conjugated ketylimines were prepared using dehydration and Lewis acid protocols from the corresponding oligofluorenones. These heteroconjugated oligomers were prepared for examining the effect of the ketylimine moiety on the photophysical properties relative to their ketone counterparts. Both the ketylimine and fluorenone containing oligofluorenes exhibited reduced fluorescence relative to their corresponding all-fluorene analogues. Temperature-dependent emission measurements and steady-state fluorescence quenching confirmed that fluorescence deactivation of the ketylimines occurred predominately by intramolecular photoinduced electron transfer (PET). This is in contrast to their oligofluorenone counterparts that dissipated their singlet excited state energy via both intersystem crossing and nonradiative internal conversion. The measured diffusion controlled fluorescence quen...

Photoluminescence of 2,7-Poly(9,9-dialkylfluorene-co-fluorenone) Nanoparticles: Effect of Particle Size and Inert Polymer Addition

Abstract: Stable nanoparticle dispersions of 2,7-poly(9,9-dialkylfluorene-co-fluorenone) (PFFO) and of PFFO/cellulose acetate butyrate (CAB) mixtures with particle size ranging between 5 and 500 nm were prep...

Fluorescence enhancement effect and the interaction between donor and acceptor

Abstract: A new theoretical equation for fluorescence enhancement effect between donor and acceptor has been introduced. By using it we determined the binding constants and numbers of binding sites of five medicines, including chlorogenic acid, forsythiaside norfloxacin, Ciprofloxacin and fluorenone, to γ-globulin.

Solvent effects of photoinduced electron transfer reactions of triplet fluorenone with amines

Abstract: The property of the lowest excited triplet state of fluorenone (FL) in acetonitrile, ethyl acetate, toluene, cyclohexane has been investigated using time-resolved laser flash photolysis. The appearances of the corresponding cation radicals and anion radicals suggest that the electron transfer reaction occurs between 3FL* and amines. Experimental results show a decrease in the quenching rate constants along with reducing solvent polarity. The change of quenching rate constants of the FL excited triplet with the three N,N-dimethylaniline derivatives are explained using the Hammett constant.

H-Bonding Controls the Regio-selectivities on the Acid-catalyzed Reaction of Fluorenone with Phenol Derivatives

Abstract: Electrophilic substitution reaction is the most widely used procedure for introducing functional groups to the aromatic ring. Activated electrophiles containing carbonyl functions such as aldehydes and acyl halides are added smoothly to phenol and its derivatives under catalytic condition. However, it is rare the reaction of carbonyl compounds like ketones with aromatic rings to form a carbon-carbon bond, and to be considered unusual due to the unfavorable equilibrium.

Synthèses dans le domaine des hydrocarbures cancérigènes. III 1: 2, 3: 4, 6: 7 — et 1: 2, 3: 4, 7:8 — tribenzofluorènes et fluorénones†

Abstract: We have synthesized 1:2, 3:4, 6:7-tribenzfluorene (IV) by reduction of the corresponding fluorenone prepared by condensation of phthalaldehyde with 4:5, 6:7-dibenzindanone. Potash fusion of 1:2, 3:4, 6:7-tribenzfluorenone gave a mixture of the following two acids which have been separated and characterized: 9-(β-naphthyl) 10-phenanthroic acid (V) 2-(9′-phenanthryl) 3-naphthoic acid (VI). The former (V) afforded, by cyclisation, 1:2, 3:4, 7:8-tribenzfluorenone from which, by reduction, 1:2, 3:4, 7:8-tribenzfluorene (IX) was obtained. The second acid (VI) gave back 1:2, 3:4, 6:7-tribenzfluorenone on cyclisation.

Synthesis and properties of poly(arylene imino) containing fluorenone group (PIKF)

Abstract: Abstract A series of novel poly(arylene imino) containing fluorenone group (PIKF) have been synthesized via palladium-catalyzed polycondensation. The thermal properties of PIKF are detected by thermal behavior (TG) and differential scanning calorimetry (DSC). UV-vis absorption spectra, photoluminescence are investigated. PIKF exhibit good thermal stability and high Tgs(>200 °C ). The optical properties of PIKF show that PIKF are interesting materials for further investigations to be presented as possible candidates for use as an electron transport layer (n-type) in multilayer LEDs.

Method for producing 9,9-biscresol fluorene

Abstract: PROBLEM TO BE SOLVED: To provide a method for industrially advantageously producing a high quality product, which is very pure and inhibits discoloring, not containing sulfur even not performing a complicated catalyst elimination operation or purification operation in a method for producing 9,9-biscresol fluorene by a reaction of fluorenone and cresol. SOLUTION: Fluorenone and cresol are made to react under reduced pressure of 30×10 3 Pa or less at a temperature range of 30-95°C under existence of a heteropolyacid catalyst, and thereby high quality 9,9-biscresol fluorene which inhibits discoloring can be produced in high yield. COPYRIGHT: (C)2010,JPO&INPIT

Method of producing 9,9-biscresolfluorene

Abstract: PROBLEM TO BE SOLVED: To provide a method of producing 9,9-biscresolfluorene suitable for industrial practice, namely a method of efficiently producing highly pure 9,9-biscresolfluorene with least discoloration in a short time while maintaining its specified quality using hydrochloric acid and a thiol as catalysts. SOLUTION: The method of producing 9,9-biscresolfluorene by allowing fluorenone and cresol to react with each other in the copresence of a thiol and hydrochloric acid, is characterized in that the ratio of fluorenone and cresol, namely fluorenone/cresol is from 1/6.5 to 1/13 (weight ratio) and the ratio of the thiol and hydrogen chloride present in the hydrochloric acid, namely thiol/hydrogen-chloride is from 1/3.2 to 1/8 (weight ratio). COPYRIGHT: (C)2011,JPO&INPIT

Process for synthesizing 2,7-dibromo fluorenone

Abstract: The invention discloses a method for synthesizing 2,7-dibromofluorenone, belonging to the chemical synthesis technical field. The method is to prepare 2,7-dibromofluorenone through direct bromination by using fluorenone and bromine as raw materials, acetic acid and a small amount of fuming sulfuric acid as reaction media, and iron-iodine as catalysts. The bromine is added at twice: a mixture of glacial acetic acid and 4/7 bromine against the total added amount of the bromine is added drop by drop first to react for two hours with the temperature controlled between 80 and 90 DEG C; then a mixture of glacial acetic acid and 3/7 bromine against the total added amount of the bromine is added drop by drop to perform backflow reaction for four hours with the temperature controlled between 110 and 120 DEG C; the whole reaction lasts for six hours. The crude products are neutralized, extracted by dichloromethane, and filtered. An organic phrase is washed by a saturated sodium bisulfite and then washed by water for a plurality of times. A product obtained after liquid separation and the solvent evaporation of the organic phrase undergoes recrystallization by absolute ethyl alcohol to give a yellow solid which is dried to obtain the 2,7-dibromofluorenone, with a yield of 92 percent. The method is characterized by simple and convenient operation, easy separation and purification of products, high yield rates and lower cost.

Synthesis and characterization of red-emission PPV copolymers containing fluorenone unit

Abstract: Two soluble copolymers of fluorenone and dioctoxylbenzene (PFN) or anthracene (PFNAn) were synthesized through Heck polymerization, and were characterized by gel permeation chromatography (GPC), FT-IR, 1H-NMR, elemental analysis and thermogravimetric analysis. The polymers possess good solubility in common organic solvents and high thermal stability with the onset decomposition temperature at higher than 410 °C. The photophysical properties of the polymers were investigated in both solutions and spin-coated films. Cyclic voltammetry results revealed that the copolymers possess higher electron affinity and reversible reduction/re-oxidation processes. Their electroluminescent properties were further investigated. PFN and PFNAn show stable and saturated red light emission with high thermal stability and high electron injection ability. This type of conjugated polymers may be promising for the applications as electron acceptors in polymer photovoltaic cells and electron transporting materials.

Carbon-carbon bond forming reaction to use fluorenone imine

Abstract: PROBLEM TO BE SOLVED: To provide a diamine analog or an amino alcohol analog in high efficiency. SOLUTION: There is provided a reaction method for forming a carbon-carbon bond comprising a reaction of a fluorenone imine compound with a compound expressed by general formula [II] or a carbonyl compound to synthesize the diamine analog or the amino alcohol analog. COPYRIGHT: (C)2011,JPO&INPIT

Improved, Highly Efficient, and Green Synthesis of Bromofluorenones and Nitrofluorenones in Water.

Abstract: A series of bromo-, nitro-, and bromonitrofluorenones were synthesized chemo- and regioselectively in 90–98% yield via electrophilic aromatic bromination and nitration under mild conditions using water as the sole solvent. These synthetic methods involve simple workup procedures and use only minimal amounts of organic solvents during the purification of products. The newly developed methods have the advantages of being cost-effective and environmentally friendly and could potentially be used for the large-scale synthesis of fluorenone derivatives.

The synthesis of pentacyclic systems by the Diels‐Alder reaction of dicycloalkenyls with cinnamic acid and related compounds

Abstract: The Diels-Alder reaction between dicycloalkenyls and aromatic α-β unsaturated acids and esters was investigated. Suitable conditions for the cyclization of the adducts leading to fluorenone conditions were found. The nature of the isomerization, observed in some cases, is discussed.

Solvent effects of photoinduced electron transfer reactions of triplet fluorenone with amines

Abstract: 在 acetonitrile 的 fluorenone (FL ) 的最低激动的三位字节状态的性质，乙醇醋酸盐，甲苯，环己烷用解决时间的激光闪光光分解作用被调查了。相应阳离子激进分子和阴离子激进分子的外观建议电子转移反应发生在 3FL* 和胺之间。试验性的结果与减少溶剂极性一起在熄灭的率常数显示出减少。熄灭 FL 的率常数的变化与三 N 使三位字节激动， N-dimethylaniline 衍生物用 Hammett 常数被解释。

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.

Palladium-Catalyzed Cyclocoupling of 2-Halobiaryls with Isocyanides via the Cleavage of Carbon—Hydrogen Bonds.

Abstract: The process provides a new and efficient approach to fluorenone imine derivatives and the nature of the isocyanide has a strong influence on the success.