Showing papers on "Fluorenone published in 2009"
TL;DR: Fluorescence spectroscopy of the aqueous dispersions reveals an efficient energy transfer to the dye in the nanoparticles, which enables a variation of the luminescence emission color between red (lambda(em) (max.) ca.
Abstract: Highly fluorescent conjugated polymer nanoparticles were prepared directly by polymerization in aqueous miniemulsion, employing Glaser coupling polymerization as a suitable step-growth reaction. A 4,4′-dinonyl-2,2′-bipyridine-modified catalyst was found to be suited for the polymerization in the aqueous heterophase system. Nanoparticles of poly(arylene diethynylenes) (arylene = 2,5-dialkyoxy phenylenes and 9,9′-dihexyl fluorene) with molecular weights in the range of Mn 104 to 105 g mol−1 and with sizes of ≤30 nm, as observed by TEM, result. N,N′-Di(4-ethynylphenyl)-1,7-di[4-(1,1,3,3-tetramethylbutyl)phenoxy]perylene-3,4:9,10-tetracarboxdiimide or 2,7-diethynylfluorenone was converted completely during the heterophase polymerization to afford colloidally stable nanoparticles of poly(arylene diethynylenes) with 0.1−2 mol % covalently incorporated perylene dye and 2−9 mol % of covalently incorporated fluorenone dye, respectively. Fluorescence spectroscopy of the aqueous dispersions reveals an efficient ener...
179 citations
TL;DR: A cationic rhodium(I)/chiral bisphosphine complex, which catalyzed the intramolecular cycloadditions of 2-naphthol-linked triynes, leading to enantioenriched helicene-like molecules is reported.
Abstract: Helicenes and helicene-like molecules have long attracted much attention because of their potential applications to optical or electronic functional materials. Therefore, flexible as well as convenient methods for their syntheses are highly desired for structural alterations and supply of sufficient quantities. The most frequently employed method for the synthesis of helicenes is the oxidative photocyclization of stilbene-type precursors, however this procedure cannot be conducted on a large scale because of the highly dilute reaction conditions. Several non-photochemical methods for the synthesis of [6]and [7]helicenes and helicene-like molecules have been developed to date. As such, transition metal mediated intramolecular [2+2+2] cycloadditions of triynes are useful methods for the synthesis of [6]and [7]helicene-like molecules through the formation of three successive rings. 6] Star and co-workers pioneered this strategy by using cobaltor nickel-mediated or catalyzed [2+2+2] cycloadditions. Following this pioneering work, we recently reported a cationic rhodium(I)/chiral bisphosphine complex, which catalyzed the intramolecular [2+2+2] cycloadditions of 2-naphthol-linked triynes, leading to enantioenriched [7]helicene-like molecules (Scheme 1). 7] Notably, non-photochemical methods that can furnish higher ordered ( [8]) helicenes and helicene-like molecules are rare. To access sterically more demanding [9]helicene-like molecules starting from commercially available 2-naphthol, we designed an intermolecular double [2+2+2] cycloaddition between a 2-naphthol-linked tetrayne and a dialkynylketone, which forms five successive rings (Scheme 2). This method would furnish various [9]helicene-like molecules, containing a densely substituted fluorenone core, by changing substituents of each cycloaddition partner. The 2-naphthol-linked tetraynes 4 were readily prepared by a three-step sequence starting from a known terminal alkyne 1 as shown in Scheme 3. A copper-mediated Scheme 1. Rhodium-catalyzed intramolecular [2+2+2] cycloaddition leading to enantioenriched [7]helicene-like molecules.
111 citations
TL;DR: A new series of heterocyclic oligomers based on the 1,3,4-oxadiazole ring were synthesized and the first fluorenone- and fumaronitrile-based n-OSCs demonstrated in transistors, however, oxadiazoles-core materials 14 and 16 were inactive in transistor devices.
Abstract: A new series of heterocyclic oligomers based on the 1,3,4-oxadiazole ring were synthesized. Other electron-deficient cores (fluorenone and fumaronitrile) were introduced to investigate the oligomers as n-channel materials. The physical properties, thin film morphologies, and field-effect transistor characteristics of the oligomers were evaluated. Thin films were deposited at different substrate temperatures and on variously coated Si/SiO(2) for device optimization. Contrary to our expectations, the thin film devices of 4 revealed p-channel behavior, and the average hole mobility was 0.14 cm(2) V(-1) s(-1) (maximum value 0.18 cm(2) V(-1) s(-1)). Compound 11 is the first example of an oxadiazole-containing organic semiconductor (OSC) oligomer in an n-channel organic field-effect transistor (OFET) and shows moderate mobilities. Non-oxadiazole-containing oligomers 9 and 12 showed n-channel OFET behavior on hexamethyldisilazane-treated and Cytop spin-coated SiO(2) in vacuum. These are the first fluorenone- and fumaronitrile-based n-OSCs demonstrated in transistors. However, oxadiazole-core materials 14 and 16 were inactive in transistor devices.
77 citations
TL;DR: The synthesis and absorption/fluorescence properties of two novel intramolecular charge transfer (ICT) compounds of (fluorene-2-yl)-(9-ethylcarbazole-3-yl) ketene and 1-phenyl-3-(fluorenone-2,yl)-5-ethyl Carbazole (9- methylcarbazoles)-2-pyrazoline were reported.
75 citations
TL;DR: It is demonstrated that the "green light" emitting fluorenones 7 can be converted to "blue light" emitters 10 by appropriate positioning of donor-acceptor and chromophoric groups onto the fluorene/fluorenone backbone.
60 citations
TL;DR: In this article, the optical properties of a series of structurally well-defined model compounds for oxidatively degraded poly(dialkylfluorenes) (PFs) are reported.
Abstract: Here, the optical properties of a series of structurally well-defined model compounds for oxidatively degraded poly(dialkylfluorenes) (PFs) are reported. Specifically, linear compounds comprising one, two, or four dihexylfluorene (F) moieties together with one fluorenone (O) moiety placed either at the end or in the center of each chain (i.e., FO, FFO, FOF, FFOFF) are studied. The results support the recent observation that the photophysics of the fluorenone-centered "pentamer" (FFOFF) is most similar to that of oxidized PFs. They further demonstrate that molecule―molecule interaction is essential to activate the green emission band. Investigations by X-ray diffraction (XRD) identify the solid-state structure of a representative member of this class of compounds and reveal inter-molecular interaction through dipole―dipole coupling between neighboring fluorenone moieties.
41 citations
TL;DR: Steady-state fluorescence showed that the fluorene singlet excited state is quenched both by fluorenone and a model aliphatic azomethine compound (14) with k(q) approximately 10(10) M(-1) s(-1), confirming that the absence of triplet signal by laser flash photolysis is a result of rapid intramolecular energy transfer to the two quencher sites.
Abstract: The photophysics and electrochemistry of fluorene and fluorenone azomethine derivatives were examined in order to understand the deactivation pathways responsible for the quenched fluorescence of these compounds, which should otherwise be fluorescent. Steady-state fluorescence showed that the fluorene singlet excited state is quenched both by fluorenone (1) and a model aliphatic azomethine compound (14) with kq ≈ 1010 M−1 s−1. The quencher concentration required to deactivate 95% of the excited singlets formed was 8.4 mM for fluorenone and 34 mM for 14. Intramolecular photoinduced electron transfer (PET) from fluorene to both 1 and 14 was found as the principle deactivation mode of the fluorene’s excited state. The high degree of conjugation of the azomethines promotes intersystem crossing to the triplet manifold by narrowing the singlet−triplet energy gap, which is also in part responsible for the reduced fluorescence observed for the fluorenone azomethine derivatives 5−11. Fluorescence quenching by PET ...
28 citations
TL;DR: 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 as mentioned in this paper.
26 citations
TL;DR: It is shown that the introduction of TPA groups leads specifically both to an antioxidant action and a reduced ET towards residual defect sites, thanks to the environmental micro-encapsulation role played by TPA units surrounding the polymer backbone.
Abstract: In order to understand the factors responsible for the improved efficiency and stability of organic light-emitting diodes (OLEDs) based on poly(9,9-dioctylfluorene) (PFO) when triphenylamine (TPA) is introduced as lateral fluorene substituent, we synthetize mono-disperse fluorene-thiophene oligomers as model compounds. Their blends with different concentrations of the fluorenone containing oligomer are studied in order to verify if only a reduction of ketonic defect sites or also an impeded energy transfer (ET) towards such sites are responsible for the suppression of the green emission band. We show that the introduction of TPA groups leads specifically both to an antioxidant action and a reduced ET towards residual defect sites, thanks to the environmental micro-encapsulation role played by TPA units surrounding the polymer backbone. As a result, the performances and colour stability of a device fabricated with TPA-substituted PFO (PFTPA) are strongly improved with respect to standard PFO device prepared in the same conditions.
22 citations
TL;DR: In this article, a co-oligomer constituted by both a thiophene sequence bearing a 3,4-dialkyl substitution, imparting processability, and by end-capping fluorenone moieties, has been synthesized.
13 citations
TL;DR: Incorporation of intercalating moieties endowed the N-nitroso compounds with DNA-cleaving ability through single-strand scission upon UV irradiation in a phosphate buffer under aerobic conditions.
Abstract: N-Nitroso compounds containing benzene, fluorene or fluorenone rings were synthesized. Photolysis of these compounds with 312-nm UV light provided the NO(*) species, the presence of which was corroborated by use of an EPR method and of 2-phenyl-4,4,5,5-tetramethylimidazolin-1-oxyl 3-oxide (PTIO) as a trapping agent. During irradiation of N-methyl-N-nitroso-9-fluorenone carboxamide (14 c) in the absence of PTIO, it underwent decomposition followed by recombination to give the heterocyclic nitric oxide radical 15. Incorporation of intercalating moieties endowed the N-nitroso compounds with DNA-cleaving ability through single-strand scission upon UV irradiation in a phosphate buffer (pH 5.0-8.0) under aerobic conditions.
TL;DR: The presented theoretical results can be useful in designing novel fluorene-fluorenone optical materials as well as understanding of excitation-relaxation phenomena which may occur in various time-dependent optical experiments.
Abstract: A systematic study of fluorenone and model oligofluorenes (trimer, pentamer, and heptamer) with a central keto defect was performed at ab initio Hartree-Fock (HF), density functional theory (DFT), configuration interaction singles (CIS), and time-dependent density functional theory (TD-DFT) levels. The main aim of this work was the investigation of the direct influence of the central keto defect on the optimal geometry, torsional potentials, and photophysical properties. From the structural point of view, the optimal all-trans electronic ground state geometries of studied oligomers exhibit a uniform torsion of ca. 44-45 degrees (HF) or 37-38 degrees (DFT). The optical excitation leads to the planarization of the fluorenone and fluorene fragments in the central part of the molecule (approximately 34 degrees for CIS and approximately 29 degrees for TD-DFT). The computed excitation and fluorescence energies show a good agreement with the experiment. These presented theoretical results can be useful in designing novel fluorene-fluorenone optical materials as well as understanding of excitation-relaxation phenomena which may occur in various time-dependent optical experiments.
TL;DR: The presence of the phenyl groups at the 9-site carbon was found necessary to eliminate fluorenone formation, and enhance the colour purity of the material.
Abstract: A homopolymer of 9,9'-bis[4-(2-(2-tetrahydropyranyloxy)ethoxy)phenyl]fluorene and its copolymers with 3,4-benzothiadiazole and 4,7-di(3(4-n-octylphenyl)-2-thienyl)-2,1,3-benzothiadiazole were synthesized to produce a series of thermally reactive blue, green, and red luminescent polymers. Thermolytic removal of the tetrahydropyran (THP) group from polymer films, rendered the films insoluble due to the formation of hydroxyl groups on the termini of side chains. Thermal removal of the THP was lowered by up to 200 °C, when acid is present in the films. These polymers were found applicable to patterning by NIR direct thermal lithography, in conjunction with a NIR dye and thermal acid generator. The presence of the phenyl groups at the 9-site carbon was found necessary to eliminate fluorenone formation, and enhance the colour purity of the material.
TL;DR: In this article, the properties of 9, 10-anthraquinone and 9-fluorenone radical anion adsorbed on the surface of oxides with electrondonating properties were studied by ESR and electron-nuclear double resonance.
Abstract: Paramagnetic complexes of 9, 10-anthraquinone and 9-fluorenone adsorbed on the surface of calcium, magnesium, zinc, zirconium, and aluminum oxides and modified Al2O3 as well as on mixed oxides were studied by ESR and electron-nuclear double resonance. Radical anions that do not interact with Lewis acid sites are generated on the surfaces of oxides with electrondonating properties (CaO, MgO). Paramagnetic complexes of the anthraquinone or fluorenone radical anion with Lewis acid sites (coordinatively unsaturated metal cations) are formed in other cases. Several types of similar complexes can be formed. Mechanisms of interaction of the probe molecules with the metal oxide surface were proposed.
TL;DR: In this article, the morphology and optical properties of two ladder-type poly(p-phenylene)s (LPFs) with the target to explore the real chromophore group of low-energy emission.
Abstract: The stability of fluorene-based compounds and polymers, especially at the bridged C-9 position, under photoirradiation and thermal treatment has widely claimed attention. The real chromophore group of low-energy emission in fluorene-based compounds and polymers is debatable for fluorenone, and the aggregate is difficult to distinguish. We report the morphology and optical properties of two fluorene-based ladder-type poly(p-phenylene)s (LPFs) with the target to explore the real chromophore group of low-energy emission. The basic comparison of LPFs with different substitutions and degraded degree testify the low-energy emission is relating to oxidized products but not packing order. The molecular distance is then adjusted by doping degraded LPF into an inert matrix, which shows that the low-energy emission is as strong as in bulk when the average molecular distance is larger than 1.2 nm. These results suggest fluorenone is the chromophore group of low-energy emission and rule out aggregate, especially fluor...
TL;DR: In this article, the reaction of ninhydrin with benzo[b]thiophene in acetic acid in the presence of a small amount of sulfuric acid afforded a novel fluorenone compound fused to benzo [b] thiophene rings.
Abstract: The reaction of ninhydrin with benzo[b]thiophene in acetic acid in the presence of a small amount of sulfuric acid afforded a novel fluorenone compound fused to benzo[b]thiophene rings. In the reaction using 2,2'-bibenzo[b]thiophene, phthalide conjoined in a spiro framework was unexpectedly isolated along with an isocoumarin derivative which is fused to benzo[b]thiophene and benzene rings. The product related to the latter was obtained in the reaction of 3,3'-bithiophene with ninhydrin. The structures of these novel heterocycles were supported by spectroscopic studies and X-ray crystallography.
TL;DR: In this paper, the optoelectronic properties of a novel fluorene derivative of 6,6′-(9H-fluoren-9,9-diyl)bis(2,3-bis)quinoxaline (BFLBBFLYQ) used for organic light-emitting diode.
Abstract: We report the optoelectronic properties of a novel fluorene derivative of 6,6′-(9H-fluoren-9,9-diyl)bis(2,3-bis (9,9-dihexyl-9H-fluoren-2-yl)quinoxaline) (BFLBBFLYQ) used for organic light-emitting diode. UV–Vis absorption, photoluminescence (PL) and electroluminescence (EL) spectra of BFLBBFLYQ and the blend doped with N,N′-biphenyl-N,N′-bis-(3-methylphenyl)-1,1′-biphenyl-4,4′-di- amine (TPD) in solid state and in solution were investigated. The results showed that BFLBBFLYQ had a PL peak at 451 nm in solid and solution states and an EL peak at 483 nm with a broad emission band, resulting from fluorenone defects. Exciplex emission was observed in BFLBBFLYQ–TPD blend solid state with a green emission peaking at 530 nm. Also the blend in solution showed solvatochromism in polarity solvent upon UV irradiation. A new absorption band appeared at around 470 nm of BFLBBFLYQ–TPD blend in chloroform solution, and disappeared when diluted in absorption spectrum. Meanwhile, a low energy emission band from 530 to 580 nm appeared and increased with material concentration and UV irradiation time.
Patent•
15 Oct 2009
TL;DR: In this paper, an acrylic compound substituted with a photo-sensitive-photo-initiator is provided to secure stable property while not causing process problems and to ensure excellent photosensitivity.
Abstract: PURPOSE: An acrylic compound substituted with a photosensitive-photoinitiator is provided to secure stable property while not causing process problems and to ensure excellent photosensitivity. CONSTITUTION: An acrylic compound substituted with a photosensitive-photoinitiator comprises at least one selected from a carbazole compound, group compound, nonimidazole compound, acetophenone compound, O-acyloxim compound, benzophenone compound, fluorenone compound, thioxanthone compound, xanthone compound, anthraquinone compound, acridine compound, dicarbonyl compound, phosphine oxide compound, the amine synergist, coumarin compound, chalcone compound, 2-benzoylmethylene, and 3-methyl-β-naphtho thiazoline.
TL;DR: In this paper, the effect of nitrogen atoms on the triplet excited state reactivity of 1,4-diaza-9-fluorenone (1) and 1, 4-daza- 9-benz[b] (2) in acetonitrile was investigated employing the nanosecond laser flash photolysis technique.
Abstract: The effect of the introduction of nitrogen atoms upon the triplet excited state reactivity of 1,4-diaza-9-fluorenone (1) and 1,4-diaza-9-benz[b]fluorenone (2), in acetonitrile, was investigated employing the nanosecond laser flash photolysis technique. The intersystem crossing quantum yield (Φces) for 1 and 2 was determined using 9-fluorenone as a secondary standard (Φces= 0.48, in acetonitrile) and for both diazafluorenones a value of Φces= 0.28 was found. Quenching rate constants ranged from 8.17x104 L mol-1 s-1 (2-propanol) to 1.02x1010 L mol-1 s-1 (DABCO) for 1,4-diaza-9-fluorenone and from 6.95x105 L mol-1 s-1 (2-propanol) to 5.94x109 L mol-1 s-1 (DABCO) for 1,4-diaza-9-benz[b]fluorenone, depending if the quenching process involves energy, hydrogen or electron transfer. A comparison between quenching rate constants for both diazaflurenones and the parent compound, i.e. 9-fluorenone, a ketone with lowest triple state of ππ* configuration, lead to the conclusion that the reactive triplet excited state for 1,4-diaza-9-fluorenone and 1,4-diaza-9-benz[b]fluorenone has ππ* configuration.
TL;DR: In this paper, a flash-vacuum distillation combination method was used to obtain the benzoic acid residue by using a large amount of residue in the production of benzyl benzoate by oxidizing toluene.
Abstract: A large amount of residue including benzoic acid, benzyl benzoate and fluorenone can form in the production of benzoic acid by oxidizing toluene. To recycle the resources and reduce secondary pollution, the treatment of benzoic acid residue was carried out to obtain the three purified materials by flash-vacuum distillation combination method, and the influence of the operating parameters, such as the top pressure, reflux ratio and top and bottom temperatures was investigated to obtain the best operating conditions. The experimental results show that the benzoic acid purity can reach 97% through distillation under the following conditions: the top pressure is 1 600 Pa, the bottom temperature is 190–200 °C, the top temperature is 130–135 °C, and reflux ratio is 5:1. The best operating conditions for benzyl benzoate distillation column are: the top pressure is 400 Pa, bottom temperature is 250–260 °C, the top temperature is 150–160 °C, and reflux ratio is 5:1. The benzyl benzoate purity can reach 95% and the fluorenone purity can reach 92%. When refined by melt crystallization, the benzoic acid purity can be improved up to 99.6%, and the purities of benzyl benzoate and fluorenone are both above 95%.
TL;DR: In this paper, a sequence consisting of palladium-catalyzed benzamide ortho-arylation/reaction with (CF3CO)2O was developed allowing a convenient one-pot synthesis of orthoarylated benzonitriles and fluorenone derivatives.
Abstract: A sequence consisting of palladium-catalyzed benzamide ortho-arylation/reaction with (CF3CO)2O was developed allowing a convenient one-pot synthesis of ortho-arylated benzonitriles and fluorenone derivatives. The outcome of this transformation is dependent on the amide N-alkyl substituent. Dehydration of ortho-arylated N-cyclohexyl-benzamides by (CF3CO)2O results in efficient production of benzonitriles. In contrast, o-arylated N-propylbenzamides are converted to fluorenone derivatives.
Posted Content•
TL;DR: The genes involved in the initial attack on fluorene by Sphingomonas sp. LB126 were investigated in this article, showing 63% and 51% sequence identity with the subunits of an angular dioxygenase from Gram-positive Terrabacter sp. DBF63.
Abstract: In this study, the genes involved in the initial attack on fluorene by Sphingomonas sp. LB126 were investigated. The ? and ? subunits of a dioxygenase complex (FlnA1A2), showing 63% and 51% sequence identity respectively, with the subunits of an angular dioxygenase from Gram-positive Terrabacter sp. DBF63, were identified. When overexpressed in E. coli, FlnA1A2 was responsible for the angular oxidation of fluorene, fluorenol, fluorenone, dibenzofuran and dibenzo-p-dioxin. Moreover, FlnA1A2 was able to oxidize polycyclic aromatic hydrocarbons and heteroaromatics, some of which were not oxidized by the dioxygenase from Terrabacter sp. DBF63. Quantification of resulting oxidation products showed that fluorene and phenanthrene were preferred substrates.
TL;DR: In this article, the electronic properties of R C C H (1), [R C HgCH3] (2), [CH3Hg C C R C c Hg CH3], [R HgC R C R] (3), [HgCR C R Hg C R ] (4), and [R R C H Hg Hg R](5) in the ground and singlet/triplet excited states were explored theoretically.
Abstract: The electronic properties of R C C H (1), [R C C HgCH3] (2), [CH3Hg C C R C C HgCH3] (3) and [R C C Hg C C R] (4) (R = fluoren-9-one) in the ground and singlet/triplet excited states were explored theoretically. Calculations indicate that geometry parameters of 1–4 change slightly on going from ground state to excited state. Experimental spectra were well reproduced by the combined TD-DFT (time-dependent density functional theory) and PCM (Polarized-Continuum Model) calculations. With increasing methylmercury and/or fluorenone groups, the featured absorption and emission bands of complexes are redshifted. The investigation reveals such a variation can tune excitation energies but not change transition nature.
Patent•
16 Jul 2009
TL;DR: The Suzuki reaction of the pyrroline nitroxide, 3-bromo-4- formyl-2,2,5,5-tetramethyl-2.5-dihydro-1H-pyrrol-1-yloxyl radical, with vinylboronic acids and subsequent Horner-Wadsworth-Emmons reaction followed by electocyclic reaction of a thus formed 1,3-5-triene and oxidation offers a new route for the synthesis of 5,6-disubstituted 1
Abstract: The Suzuki reaction of the pyrroline nitroxide, 3-bromo-4- formyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-1-yloxyl radical, with vinylboronic acids and subsequent Horner-Wadsworth-Emmons reaction followed by electocyclic reaction of the thus formed 1,3,5-triene and oxidation offers a new route for the synthesis of 5,6-disubstituted 1,1,3,3-tetramethylisoindolin-2-yloxyl radicals. The alternative Diels-Alder reaction pathway sometimes resulted in poor yields. Starting from 5-(ethoxycarbonyl)-1,1,3,3-tetramethyl-6-phenylisoindolin-2-yloxyl radical we obtained a spin-labeled fluorenone.
Patent•
29 Apr 2009
TL;DR: In this paper, a streptomyces sp.DUT003 with the preserving number of CGMCC2518 was used in the reduction of rigid macrocyclic aromatic ketone such as substituted fluorenone.
Abstract: The invention relates to the field of biocatalysis, and in particular relates to a streptomyces (Streptomyces sp.DUT003 with the preserving number of CGMCC2518) and application thereof in the reduction of rigid macrocyclic aromatic ketone such as substituted fluorenone. With the streptomyces, aromatic ketone, in particular the rigid macrocyclic aromatic ketone such as the substituted fluorenone can be reduced with high efficiency; products are aromatic alcohol and the aromatic alcohol with optical activity, the problems of synthesizing the aromatic alcohol and the aromatic alcohol with optical activity chemically and industrially are solved, the conversion rate can reach between 89 and 98 percent, the products have high stereoselectivity, and the ee value is between 83 and 100 percent. The streptomyces has the advantages of easy culture, mild reduction and reaction condition, simple operation steps, less environmental pollution, and good prospect of industrial application and development.
Patent•
02 Sep 2009
TL;DR: In this article, a 2,4,6-tris(2,6,dimethoxy-4-fluorene hydrazone phenoxy)-1,3,5-triazine and method for preparing the same was presented.
Abstract: The invention discloses 2,4,6-tris(2,6-dimethoxy-4-fluorene hydrazone phenoxy)-1,3,5-triazine and method for preparing the same. The method comprises the following steps: using cyanuric chloride as a raw material and using acetone and water as a solvent to react with syringaldehyde so as to obtain 2-chloro-4,6-bis(2,6-dimethoxy-4-formyl phenoxy)-1,3,5-triazine A; using pyridine as a solvent to react the compound A with the syringaldehyde to obtain 2,4,6-tris(2,6-dimethoxy-4-formyl phenoxy)-1,3,5-triazine B; and then performing reflux reaction on the compound B and fluorenone hydrazone in a mixed solvent of acetonitrile and ethanol to obtain the 2,4,6-tris(2,6-dimethoxy-4-fluorene hydrazone phenoxy)-1,3,5-triazine C. The compound emits blue light, has better fluorescent light-emitting characteristic, and can be applied as an organic light-emitting material or an ultraviolet absorbent.
TL;DR: In this paper, structural and chromophoric effects on the formal intramolecular photoredox reaction discovered in our laboratory for aromatic ketones such as benzophenone and anthraquinones in aqueous solution were investigated.
Abstract: To further explore the structural and chromophoric effects on the formal intramolecular photoredox reaction discovered in our laboratory for aromatic ketones such as benzophenone and anthraquinones in aqueous solution, we have investigated whether this photochemistry can be applied to xanthones, fluorenones, and benzophenones that are “extended” by a conjugated phenyl ring where the oxidizable group is distal to the benzophenone. It was found that 2-(hydroxymethyl)xanthone ( 6 ) exhibited sufficient photoactivity that the intramolecular photoredox reaction was observable under neutral conditions whereas 2-(hydroxymethyl)fluorenone ( 7 ) displayed only very low but clean photoreactivity in acid. The last feature of this study focuses on the extension of the electronic transmission from the carbonyl functional group to the benzylic alcohol, by insertion of an additional phenyl group, to give a biphenyl (phenylene) structural feature. The addition of the phenyl group gives rise to bichromophoric molecules ( 8 – 10 ) rather than monochromophoric substrates studied in the past. We find that the location of the hydroxymethyl substituent on the attached phenyl ring plays a pivotal role in the overall photobehaviour: only the ortho -substituted compound gave evidence of an intramolecular photoredox reaction, while the meta - and para -substituted compounds primarily exhibited photobehaviour that can be interpreted as an “aborted” intramolecular redox process. Overall, the results show that photoredox or related reaction can occur for all of these systems but added complexities make them less useful compared to what was observed for the “parent” benzophenone system.
01 Jan 2009
TL;DR: In this article, the principles of DSSC were discussed, including panchromatic sensitizers, organic dyes, quantum dot as sensitizer, and solid-state dye-sensitized solar cells.
Abstract: 2 Introduction 3 General Principles of DSSC 7 Panchromatic sensitizers 9 Organic dyes, quantum dot as sensitizers 15 Solid-state dye-sensitized solar cells 16 Fullerene nanotubes as solar cells 20 Photovoltaic performance stability (on the N3 dye example) 22 Dye structures used in DSSL 24 Theoretical approach 34 Antenna Systems 35 White OLEDs 42 Results and discussion 45 Synthesis 47 Alkylation 48 Sonogashira Coupling 50 Amine Alkylation (Ullmann reaction) 55 Iodination of fluorenone 56 Spectroscopy 56 Experimental Part 61 References 66