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Surfactant-Concentration Effects in Photoinduced Electron Transfer from Pyrene to Cupric Ions in Sodium Dodecyl Sulfate Micelle Solutions
The decay of pyrene fluorescence and the quantum yield of pyrene cations were measured by using the laser photolysis method in sodium dodecyl sulfate (SDS) micelle solutions containing both pyrene and cupric dodecyl sulfate at 40 deg C.The decay curve of the pyrene fluorescence deviates from the first-order rate law at SDS concentrations below 0.2 M, as alredy known, but becomes first order at higher SDS concentrations.The rate shows incontinuity between 0.2 and 0.5 M SDS.The cation quantum yield remarkably increases with the SDS concentration: For 10 mM of cupric ion, the quantum yields were 0.25 and 0.60 at SDS concentrations of 0.05 and 0.8 M, respectively.These results can be explained in terms of involvement of large rodlike micelles in which the portion of the net electron transfer in quenching is larger than in usual spherical micelles.
Nakamura, Takashi,Kira, Akira,Imamura, Masashi
p. 3435 - 3441
(1984)
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THE ALKALI METAL REDUCTION OF PYRENE-STRUCTURAL AND PREPARATIVE ASPECTS
Reduction of pyrene with alkali metals yields the corresponding dianion salts.The solvents, counterion and temperature must be carefully selected since side reactions such as protonation (e.g. in liquid ammonia) or cleavage of the etheral solvent occur readily.Moreover, the spectroscopic characterization of the dianion is complicated by rapid electron transfer processes.There is no experimental evidence for distorted dianion structures or for further reduction of pyrene toward a tetraanion.Knowledge of the ionic pi-structures is essential for an understanding of reductive alkylation processes.
Schnieders, C.,Muellen, K.
p. 1701 - 1712
(1984)
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Coulson
p. 1298,1304
(1937)
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Photoionization of 10-methylphenothiazine, N,N,Na?2Na?2-tetramethylbenzidine, and pyrene in Cr-AlMCM-41 molecular sieves
Photoionization of 10-methylphenothiazine (PC1), N,N,Na?2,Na?2-tetramethylbenzidine (TMB), and pyrene (Py) impregnated into mesoporous AlMCM-41 ion-exchanged with Cr(III), as an electron acceptor, to give Cr-AlMCM-41 was investigated. Cation radicals (PC1a?￠+, TMBa?￠+, Pya?￠+) are produced by 320 nm light at room temperature and characterized by electron spin resonance (ESR) and UV-vis diffuse reflectance spectroscopy. The chromium ion concentration was varied from Si/Cr = 52 to 121. Cr-AlMCM-41 with the intermediate concentration of Si/Cr = 80 exhibits the greatest electron acceptor ability and shows the highest photoionization efficiency photoionized. The photoionization efficiency also depends on the type of photoionizable molecule impregnated into mesoporous Cr-AlMCM-41 with PC1 being the most efficiently photoionized. The calcination temperature used before impregnation controls the oxidation state of chromium ions to Cr3+ or Cr5+/Cr6+, which also affects the photoionization efficiency. Cr-AlMCM-41 with Cr5+ gives about 4 times higher photoionization efficiency than with Cr3+. Cr-AlMCM-41 is shown to be a promising heterogeneous host for the efficient formation of photoinduced cation radicals to achieve long-lived charge separation in solid-state systems.
Sinlapadech, Sunsanee,Koodali, Ranjit,Krishna,Kevan, Larry
p. 6251 - 6257
(2002)
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Formation and decay of pyrene radical cation and pyrene dimer radical cation in the absence and presence of cyclodextrins during resonant two-photon ionization of pyrene and sodium 1-pyrene sulfonate
Formation and decay of pyrene radical cation and pyrene dimer radical cation during resonant two-photon ionizations (TPI) of pyrene (Py) and sodium 1-pyrene sulfonate (NaPySA) in the absence and presence of cyclodextrins were studied with visible and near IR transient absorption measurement using 355-nm laser flash photolysis technique. Ionization of Py and 1-pyrene sulfonate anion (PySA-) occurred within the laser flash (5 ns) to give Py radical cation (Py?+) and PySA- radical cation (Py ?+SA-) having Py?+ chromophore. Dimerizations of Py?+ and Py and of Py?+SA - and PySA- were observed to give the dimer radical cations (Py2?+ and Py2 ?+(SA-)2) based on time-resolved measurements of the charge resonance (CR) band. The TPI of PySA- was also examined in the presence of β- and γ-cyclodextrins (βCD and γCD, respectively). Py2?+(SA-) 2 in the cavity of two γCDs having fully overlapped structure showed the CR band around 1700 nm, while Py2 ?+(SA-)2 in the cavity of two βCD having partially and fully overlapped structures indicated the CR bands around 1500 or 1700 nm, respectively. On the basis of formation and decay rates of Py2?+(SA-)2, bimolecular formation of Py2?+(SA-)2 and the neutralization are inhibited in the cavities of CDs. Selective formation of the fully overlapped structure of Py2?+(SA -)2 in the cavity of two γCDs within a laser flash is explained by direct TPI of two PySA-s with the parallel structure of two Py chromophores in two PySA-s in the cavity of two γCDs.
Hara, Michihiro,Tojo, Sachiko,Kawai, Kiyohiko,Majima, Tetsuro
p. 3215 - 3220
(2004)
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Laser-Induced Photoionization of Two-Electron-Reduced Viologen
Laser photolysis of two-electron-reduced 1,1'-bis(3-sulfonatepropyl)-4,4'-bipyridinium (PSV2-) produced by the reduction of PVS0 with Na2S2O4 in the cationic micelles of hexadecyltrimethylammonium chloride induced the photoionization of PVS2- to generate comparable amounts of PVS-. and hydrated electrons.Pyrene with a considerably negative potential of -2.09 vs.SCE was observed to be reduced in the system.
Usui, Satoshi,Inoue, Hiroshi,Ishida, Hitoshi,Ohkubo, Katsutoshi
p. 2089 - 2092
(1993)
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Saha,Bagchi
p. 1392,1395
(1955)
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Reactivity of the 1-hydropyrenyl anion towards α,ω-dibromoalkanes
The reactivity of the 1-hydropyrenyl mono-anion (1-) towards 1,2-dibromoethane, 1,3-dibromopropane and 1,4-dibromobutane has been examined.Six novel products were isolated from these reactions and characterised: spiro (2), 1,3a-dihydro-1,3a-ethanopyrene (3), 9,10,11, 11a-tetrahydro-8bH-cyclopentapyrene (4), 2,3,3a,12a-tetrahydro-1H-cyclopentapyrene (5), 3a-(3-bromopropyl)-3,3a-dihydropyrene (6) and 8b,9,10,11,12,12a-hexahydrobenzolpyrene (7).The formation of these products could be rationalised by initial attack of the dibromoalkane at positions 3a and 5 of 1-.Deprotonation of the initial ω-bromoalkyldihydropyrenes leads to intramolecular alkylation, the course of which depends on the length of the alkyl chain.Attempts to aromatize the products resulted, except in the case of 5, in the fully aromatic pyrene derivatives cyclopentapyrene, benzopyrene, pyrene and the new cyclopenta-fused pyrene derivative, 10,11-dihydro-9H-cyclopentapyrene (9).
Dijk, Joost T. M. van,Lugtenburg, Johan,Cornelisse, Jan
p. 1489 - 1496
(1995)
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Electroreduction of 3-bromopyrene in DMF. A new organic electrochemical oscillator
The reduction of 3-bromopyrene in DMF at a mercury electrode for scan rates lower than 0.1 V s-1 is accompanied by a slow adsorption of an intermediate, resulting in a catalytic behaviour. The current oscillations take place in a region of the negative faradaic impedance.
Jaworski, Jan S.,Leszczynski, Piotr,Pawlowski, Slawomir
p. 1715 - 1721
(1996)
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Dynamics of a supramolecular capsule assembly with pyrene
Water-soluble octaacid cavitands (OAs) form dimeric capsules suitable for guest incorporation. Our studies reveal that the mechanism of pyrene (Py) binding involves the rapid (1 ms) formation of the Py?OA complex followed by slower binding with the second OA. The dissociation of the capsular OA?Py?OA complex occurs with a lifetime of 2.7 s, which is 5 orders of magnitude slower than the microsecond opening/closing ("breathing") previously observed to provide access of small molecules to the encapsulated guest. These different dynamics of the capsules have a potential impact on how the chemistry of included guests could be altered.
Tang, Hao,De Oliveira, Carla Santos,Sonntag, Gage,Gibb, Corinne L. D.,Gibb, Bruce C.,Bohne, Cornelia
p. 5544 - 5547
(2012)
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Phototransformations of environmental contaminants in models of the aerosol: 2 and 4-Nitropyrene
A comparative photochemical study of 2- and 4-nitropyrene (2- and 4-NO2Py) in different organic solvents was performed in order to provide information on the fate of these contaminants in models of the atmospheric aerosols. The isomers presented small photodegradation yields, 10?4–10?5 for 4-NO2Py and 10?5–10?6 for 2-NO2Py, demonstrating the low reactivity of the excited states and intermediate species that participate in their photodegradation. Photoproducts such as 4,5-pyrenedione, 4-hydroxypyrene, aminopyrene and pyrene were identified during the irradiation of 4-NO2Py. Substantial differences were observed in the photodegradation yields, and type and relative yields of the photoproducts of the 2-NO2Py and 4-NO2Py when compared to those of 1-NO2Py. These differences were related with the orientation of the nitro group and with differences in intersystem crossing rates which affect the yields of the pyrenoxy radical (PyO) and of the (π,π*) triplet state, principal precursors in their photodegradation. The smallest photodegradation yield was for 2-NO2Py due to the lack of interaction between the nitro group and the aromatic moiety thus resulting in a low yield of formation of the PyO radical. In the presence of O2, the photodegradation quantum yields of 4-NO2Py were reduced in all solvents due the quenching of the (π,π*) triplet state, and 4-aminopyrene was not observed thus demonstrating that its formation occurs from this state. These results suggest that in atmospheric aerosols containing an organic liquid-like layer, the nitropyrene isomers will show low photoreactivity resulting in an increase in their residence time in the atmosphere. An increase in reactivity is expected when the excited nitropyrenes are nearby substances with hydrogen donor capacities such as phenols. The photoproducts formed in the transformation could increase the toxicity of the particulate matter in the atmosphere.
García-Berríos, Zulma I.,Arce, Rafael,Burgos-Martínez, Melanie,Burgos-Polanco, Natalia D.
p. 131 - 140
(2017)
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Photophysical Properties of Pyrene in Zeolites: A Direct Time-Resolved Diffuse Reflectance Study of Pyrene Anion Radicals in Zeolites X and Y
The formation of pyrene anion radicals (Py.-) in the supercage of different alkali-ion-exchanged zeolites X and Y was studied using direct time-resolved diffuse reflectance techniques.Many factors such as the Si/Al ratio, the nature of charge balancing cations, the preactivation temperature, the pyrene loading, the state of hydration, and the nature of the surfaces (external versus internal) were examined in order to understand the formation and stabilization of Py.- in these samples, and also the mechanism of the photoinduced electron transfer processes.The results show that photoinduced electron transfer does not occur from pyrene to pyrene in the zeolites but occurs between pyrene molecule and the acidic and basic sites of the zeolites.The basic sites of the zeolites, responsible for the formation of Py.-, are framework oxygen.Stabilization of Py.- requires the special environment of the zeolite supercage; it is noteworthy that Py.- cannot be formed on the external surface of a zeolite.The formation of Py.- in the different alkali-ion-exchanged zeolites X- and Y follows the order of basicity of these samples, which is calculated using the Sanderson electronegativity equalization principle.Preactivation of the samples at temperatures of 350, 550, and 750 deg C does not affect the ratio of the anion to cation, Py.-/Py.+, yields.Posthydration of the samples alters the photophysical processes in the zeolites and gives rise to an increase in the yield of Py.-.At low light intensities, the photoinduced electron transfer follows a single-photon increase in the yield of Py.-.At low light intensities, the photoinduced electron transfer follows a single-photon mechanism.
Liu, Xinsheng,Iu, Kai-Kong,Thomas, J. Kerry
p. 7877 - 7884
(1994)
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Bachmann,Edgerton
p. 2970,2972
(1940)
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A forgotten olefin: A convenient one-pot cascade reaction involving Suzuki-Miyaura and Mizoroki-Heck couplings to form (E)-1,2-Di(pyren-1-yl) ethylene
The addition of 0.5 equiv of vinylboronic acid pinacol ester I to 1-bromopyrene derivative 3 in the presence of [Pd(PPh3)4] and K 2CO3 induced a cascade reaction involving SuzukiMiyaura and MizorokiHeck couplings and afforded (E)-1,2-di(pyren-1-yl)ethylene derivative 1b. An alternative synthesis of 1b was carried out by an olefin metathesis. Formed 1b showed absorption bands in the visible region and a low oxidation potential attributable to a narrow HOMO-LUMO gap.
Yamashita, Ken-Ichi,Kimura, Keisuke,Tazawa, Shin,Asano, Motoko S.,Sugiura, Ken-Ichi
p. 1459 - 1461
(2011)
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The Thermal Isomerization of Dicyclopentaheptalene (Azupyrene) to Pyrene
Dicyclopentaheptalene (azupyrene) has been synthesized from cyclopentanone which, in turn, was prepared from 13C-labeled cyanide and 13C-labeled iodomethane.Thermal isomerization of the labeled azupyrene gave pyrene.The only proposed mechanism consistent with this result are the radical-initiated methylene walk and that involving a peripheral bicyclobutane intermediate.These mechanisms are also in agreement with previous results from the isomerization of 1-methylazupyrene except for an additional minor product in the latter experiment.Evidence for the automerization of pyrene under the thermal isomerization conditions has been obtained.
Anderson, Arthur G.,Haddock, Ralph D.
p. 550 - 552
(1991)
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Reflectance Spectroscopic Studies of the Cation Radical and the Triplet of Pyrene on Alumina
The triplet state and the cation radical of pyrene are produced on excitation of pyrene adsorbed on γ-alumina.The characteristic absorption spectra of these two alumina bound transients are similar to those in solution and exhibit absorption bands at 415 and 450 nm for the triplet and the cation, respectively.The triplet state decays exponentially with a lifetime of 5.1 ms, while the cation decays in a more complicated fashion which can be described by a Gaussian distribution of the logarithm of the rate constant at various adsorption sites.Movement of ferrocene to the triplet state on the surface quenches the triplet via energy transfer.The bimolecular quenching rate constants of pyrene triplet by ferrocene are 3.31 x 1011, 2.63 x 1011, and 2.20 x 1011 m2 mol-1 s-1 for alumina at pretreatment temperatures of 130, 250, and 350 deg C, respectively.Pretreatment of the alumina surface at high temperatures decreases the number of surface hydroxyl groups.These bind adsorbed molecules less strongly than the acidic sites formed at the high pretreatment temperature.Hydration of the surface by small amounts of coadsorbed water increases the number of surface hydroxyl groups and enhances the degree of dynamic quenching.The formation of the cation radical of pyrene on alumina is a two-photon process, and the cation radical is quenched dynamically by ferrocene.The studies clearly distinguish the role played by heat activation of alumina on the diffusion and rates of photoinduced process on the surfaces.A comparison with similar results on silica shows that adsorbed molecules are less mobile on alumina.
Pankasem, Surapol,Thomas, J. Kerry
p. 6990 - 6996
(1991)
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Towards modelling light processes of blue-light photoreceptors. Pyrene-isoalloxazine (flavin)-phenothiazine triad: Electrochemical, photophysical, investigations and quantum chemical calculations
The triad 6 containing the phenothiazine-isoalloxazine couple as donor-acceptor redox unit and pyrene as antenna absorbing in the UV-A region has been designed to mimic the light processes of natural photoreceptors. By cyclic voltammetry it is shown that the redox chemistry of the three subunits of triad 6 behave almost independently, indicating no electronic coupling between the subunits in the ground state. Triad 6 exhibits three accessible redox states with one oxidation and two reduction waves due to the formation of the phenothiazine radical cation and isoalloxazine and pyrene radical anions. UV/Vis/NIR spectroelectrochemistry reveals the generation of the protonated isoalloxazine dianion on reduction which is formed in the non-polar solvent in a reduction-protonation-reduction step (two-electron transfer process) and which is attributed to intermolecular proton transfer from the amide group to the electrochemically reduced isoalloxazine radical anion. Evidences for the photoinduced energy and electron transfer within the triad are provided by steady state and time-resolved absorption and fluorescence measurements. Spectroscopic studies displayed that upon excitation the pyrene emission was dramatically quenched in the dyad 4. This is most likely due to the energy transfer from pyrene to the isoalloxazine units as the absorption band of isoalloxazine overlaps with the pyrene emission band leading most likely to a CT state of the isoalloxazine/phenothiazine type. Quenching of the phenothiazine fluorescence in triad 6 was also ascribed to the spectroscopic overlap between the emission spectrum of phenothiazine and absorption spectrum of isoalloxazine. Again, photoinduced electron transfer from phenothiazine to isoalloxazine is expected to be the cause for the quenching of the isoalloxazine emission in the dyad 5. Molecular orbital calculations for compound 5 showed a complete electron transfer from phenothiazin to isoalloxazine.
Shen, Zhen,Prochazka, Roman,Daub, Joerg,Fritz, Norbert,Acar, Nursel,Schneider, Siegfried
p. 3257 - 3269
(2003)
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Thermolysis of benzo[c]phenanthrene-5,6-dicarboxylic anhydride and 6H-benzo[cd]pyren-6-one. Entries to the combustion effluents benzo[ghi]fluoranthene and cyclopenta[cd]pyrene
Thermolysis of the oxy-PAH benzo[c]phenanthrene 5,6-dicarboxylic anhydride (3) and 6H-benzo[cd]pyren-6-one (4) gave the abundant C18H10 CP-PAH combustion effluents benzo[gh]]fluoranthene (1) and cyclopenta[cd]pyrene (2).
Sarobe, Martin,Jenneskens, Leonardus W.,Wiersum, Ulfert E.
p. 4689 - 4692
(1997)
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Velthorst,N.H.,Hoijtink,G.J.
p. 209 - 212
(1967)
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Synthesis and Hydropyrolysis of Bis-trimethylsilyl Substituted 3-(4H-Cyclopentaphenanthrylidene)-1,4-pentadiyne. A New Route to Corannulene
3-(4H-Cyclopentaphenanthrylidene)-1,5-bis-(trimethylsilyl)-1,4-pentadiyne (3) was synthesized and converted by hydropyrolysis into corannulene (1) besides others in reasonable yields.It represents a new route of the simplest bowl-shaped polycyclic aromatic hydrocarbon starting from an easily accessible precursor.
Zimmermann, Gerhard,Nuechter, Uta,Hagen, Stefan,Nuechter, Matthias
p. 4747 - 4750
(1994)
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Metacyclophanes and Related Compounds. 19. Reaction of 8-Methoxymetacyclophanes with Iodine in Benzene Solution. A Preparative Route of Pyrene
When 8-methoxymetacyclophanes are treated with iodine in boiling benzene, the corresponding tetrahydropyrenes (8) are obtained in good yield.The AlCl3-catalyzed trans-tert-butylation of 8 effected loss of the tert-butyl group to give 10a-c, which were easily dehydrogenated with DDQ to afford the corresponding pyrene derivatives.
Tashiro, Masashi,Yamato, Takehiko,Kobayashi, Kazumasa,Arimura, Takashi
p. 3196 - 3199
(1987)
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Base-Selective Five- versus Six-Membered Ring Annulation in Palladium-Catalyzed C–C Coupling Cascade Reactions: New Access to Electron-Poor Polycyclic Aromatic Dicarboximides
Palladium-catalyzed base-selective annulation of dibromonaphthalimide to different aryl boronate esters by combined Suzuki–Miyaura cross-coupling and direct C?H arylation afforded a series of new five- and six-membered ring annulated electron-poor polycyclic aromatic hydrocarbons. Cesium carbonate (Cs2CO3) as auxiliary base in these C?C coupling cascade reactions led exclusively to six-membered ring annulation, while the use of organic base diazabicycloundecene (DBU) afforded the corresponding five-membered ring annulated products. This base-dependent selective mode of annulation is attributed to different mechanistic pathways directed by the applied base. The selective annulation was revealed by single crystal X-ray analysis of the respective five- and six-membered ring annulated products. The optical and redox properties of the new polycyclic aromatic dicarboximides were characterized by UV/Vis absorption and fluorescence spectroscopy and cyclic voltammetry.
Seifert, Sabine,Schmidt, David,Shoyama, Kazutaka,Würthner, Frank
p. 7595 - 7600
(2017)
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Origin of Pyrene under High Temperature Conditions in the Gas Phase. The Pivotal Role of Phenanthrene
4-Ethynylphenanthrene (15), and the latent precursors for 2-ethynyl- (18) and 3-ethynylphenanthrene (19), viz., 2-(1-chloroethenyl)- (16) and 3-(1-chloroethenyl)phenanthrene (17), respectively, have been subjected to flash vacuum thermolysis (FVT). Whereas at 800°C 15 is quantitatively converted into pyrene (1), 16 and 17 only give 18 and 19, respectively. Both 18 and 19 contain redundant ethynyl substituents, i.e., after ethynyl-ethylidene carbene equilibration neither five-nor six-membered ring formation can occur by carbene C-H insertion. At T ≥ 1000°C 16 and 17 gave pyrolysates containing the same set of 11 (non)-alternant polycyclic aromatic hydrocarbons (PAH), albeit in a different ratio. The different product ratio suggests that redundant ethynyl substituents migrate along the phenanthrene periphery presumably via transient cyclobuta-PAH intermediates toward positions suitable for either five- or six-membered ring formation by carbene C-H insertion. The results provide an explanation for the ubiquitous formation of pyrene (1), acephenanthrylene (9), and fluoranthene (3) during (incomplete) combustion. Phenanthrene (2) appears to be a point of divergence in PAH growth by C2 addition.
Sarobe, Martin,Jenneskens, Leonardus W.,Steggink, Ralph G. B.,Visser, Tom
p. 3861 - 3866
(1999)
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Development of a dual-electrolysis stopped-flow method for the observation of electrogenerated chemiluminescence in energy-sufficient systems
New methodology for the measurement of electrogenerated chemiluminescence (ECL) has been developed by using a dual-electrolysis stopped-flow system. Using this method, the ECL from 'energy-sufficient' systems composed of different kinds of ion radicals can be easily observed by mixing both the electrolyzed solutions directly. The apparatus and method have been described in detail as well as the ECL observations for various energy-sufficient systems. In particular, in the reaction between the thianthrene (TH) cation radical and the pyrene (PY) anion radical, it was found that the emission spectra changed with the addition of the precursors, reflecting both complex electron- and energy-transfer processes in solution. The present results indicate that the electron- and energy-transfer reactions changed significantly, depending on the type of molecules. The ECL observation with the addition of the third molecule was also informative to compare the ease of the formation of the excited states. It was clarified that the excited states of 9,10-diphenylanthracene and rubrene are easily formed compared with those of TH and PY.
Oyama, Munetaka,Okazaki, Satoshi
p. 5079 - 5084
(1998)
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INVESTIGATION OF THE FORMATION OF HIGH MOLECULAR HYDROCARBONS AND SOOT IN PREMIXED HYDROCARBON-OXYGEN FLAMES.
Measurements of concentrations of high molecular hydrocarbons in laminar flat low pressure flames with various hydrocarbons under sooting conditions are reported. The results show that for all fuels investigated in that region of the flames where the bulk of soot is formed besides the main combustion products some characteristic groups of species are to be found. Within these groups of species only few fuel specific characteristics are stated. The main fuel specific influence lies in the relative concentration for the species. A reaction scheme for the qualitative explanation of the results found is discussed.
Bockhorn,Fetting,Wenz
p. 1067 - 1073
(1983)
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A recyclable Au(I) catalyst for selective homocoupling of arylboronic acids: Significant enhancement of nano-surface binding for stability and catalytic activity
Au nanoparticles stabilized by polystyrene-co-polymethacrylic acid microspheres (PS-co-PMAA) were prepared and characterized via X-ray diffraction (XRD), and transmission electron microscope (TEM). The Au nanoparticles supported on the microspheres showed highly selective catalytic activity for homo-coupling reactions of arylboronic acids in a system of aryl-halides and arylboronic acids. X-ray photoelectron spectroscopy (XPS) spectra of the catalyst shows large amounts of Au(l) complexes band to the surface of the Au nanoparticles, which contributes to the selective homocoupling of the arylboronic acids. More importantly, this supported Au complex is a highly recyclable catalyst. The supported Au catalyst can be recycled and reused at least 6 times for a phenylboronic acid reactant, whereas the parent complex shows very low catalytic activity for this compound. The high catalytic activity of this material is attributed to: (1) the high surface to volume ratio which leads to more active sites being exposed to reactants; (2) the strong surface binding of the Au nanoparticle to the Au(1) complexes, which enhances both the stability and the catalytic activity of these complexes. Copyright
Zhang, Xin,Zhao, Haitao,Wang, Jianhui
p. 5153 - 5160
(2010)
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Pulse Radiolysis of trans-Stilbene in Tetrahydrofuran. Spektral Shift and Decay Kinetics of the Radical Anions in the Presence of Quaternary Ammonium Salts
Pulse radiolysis of trans-stilbene (St) in tetrahydrofuran (THF) solution was carried out in the presence of quaternary ammonium salts, such as Bu4NPF6, Bu4NI, Bu4NBPh4, CeMe3NPF6, PhMe3NPF6, and BzMe3NPF6 (Bu, butyl; Ce, cetyl; Me, methyl; Ph, phenyl; and Bz, benzyl).The absorption peak of the radical anions, St-., was shifted to shorter wavelengths in the presence of the salts.The magnitude of the shift depends on the substituent groups of the quaternary ammonium cations.It is suggested that St-. forms contact ion pairs with the quaternary ammonium cations.The decay rate of St-. decreases with increasing salt concentration and becomes steady.The rate constants for the neutralization reaction of St-. with the solvent counterions, THF(H+), have been determined in the absence and presence of Bu4NPF6; in the latter case, the reaction occurs between the ion pairs St-./Bu4N+ and THF(H+)/PF6-.The results for other aromatic compounds such as bibhenyl, anthracene, and pyrene are also presented.Comparison was made with the effect of NaBPh4.
Yamamoto, Yukio,Nishida, Shoichi,Ma, Xiao-Hua,Hayashi, Koichiro
p. 1921 - 1924
(1986)
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Effects of an oxidation catalytic converter and a biodiesel fuel on the chemical, mutagenic, and particle size characteristics of emissions from a diesel engine
This study was conducted to obtain additional information on exhaust emissions with potential health importance from an indirect injection diesel engine, typical of those in use in underground mines, when operated using a soy-derived, fatty-acid mono-ester (or biodiesel) fuel and an oxidation catalytic converter (OCC). Compared to emissions with the diesel fuel without the OCC, use of the diesel (D2) and biodiesel fuel with the OCC had similar reductions (50-80%) in total particulate matter (TPM). The solid portion of the TPM was lowered with the biodiesel fuel. Particle-associated polynuclear aromatic hydrocarbon and 1-nitropyrene emissions were lower with use of the biodiesel fuel as compared to the D2 fuel, with or without the OCC. Vapor- phase PAH emissions were reduced (up to 90%) when the OCC was used with either fuel. Use of the OCC resulted in over 50% reductions in both particle and vapor-phase-associated mutagenic activity with both fuels. No vapor- phase-associated mutagenic activity was detected with the biodiesel fuel; only very low levels were detected with the D2 fuel and the OCC. Use of the OCC caused a moderate shift in the particle size/volume distribution of the accumulation mode particles to smaller particles for the diesel fuel and a reduction of particle volume concentrations at some of the tested conditions for both fuels. The nuclei mode did not contribute significantly to total particle volume concentrations within the measured particle size range (~0.01-1.0 μm). The biodiesel fuel reduced total particle volume concentrations. Overall, use of this OCC for the engine conditions tested with the biodiesel fuel, in particular, resulted in generally similar or greater reductions in emissions than for use of the D2 fuel. Use of the biodiesel fuel should not increase any of the potentially toxic, health- related emissions that were monitored as part of this study. Detailed information necessary to evaluate impact of using a biodiesel fuel on potentially health-related emissions from a diesel engine typical of those used in many underground mining operations are provided. Compared to emissions with the diesel fuel without the oxidation catalytic converter (OCC), use of the diesel (D2) and biodiesel fuel with the OCC had a similar reductions in total particulate matter (TPM). The solid portion of the TPM was lowered with the biodiesel fuel. Particle-associated polynuclear aromatic hydrocarbon and 1-nitropyrene emissions were lower with use of the biodiesel fuel as compared to the D2 fuel, with or without the OCC.
Bagley, Susan T.,Gratz, Linda D.,Johnson, John H.,McDonald, Joseph F.
p. 1183 - 1191
(1998)
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Effects of Quaternary Ammonium Salts on Reactions of Aromatic radical Anions Formed in Tetrahydrofuran by Pulse Radiolysis
Pulse radiolysis of biphenyl (BP) and pyrene (Py) in tetrahydrofuran (THF) solution was carried out in the presence of various kinds of quaternary ammonium salts, such as Bu4NPF6, Bu4NBF4, Bu4NI, BzMe3NPF6 and PhMe3NPF6 (Bu, butyl; Me, mthyl; Bz, benzyl; and Ph, phenyl).The decay behaviors of the radical anions, BP-. and Py-., are significantly affected by the addition of the salts.The anions of the salts, PF6-, BF4-, and I-, are considered to form ion pairs with the solvent counterions, THF(H+), resulting in a retardation of the neutralization reactions.The rate constants for the neutralization reactions have been determined in the absence and presence of Bu4NPF6.The addition of BzMe3NPF6 (or PhMe3NPF6) accelerates the decay of BP-. and retards the decay of Py-., depending on the rates of reactions of the radical anions with BzMe3N+ (or PhMe3N+).The reactivity of BP-. in the electron transfer to Py seems to be reduced in the presence of Bu4NPF6.The effect of Bu4N+ on the reactions of the radical anions is discussed.
Yamamoto, Yukio,Nishida, Shoichi,Yabe, Katsuyoshi,Hayashi, Koichiro,Takeda,Seishi,Tsumori, Kunihiko
p. 2368 - 2372
(1984)
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Azupyrene. Thermal Isomerization. Nitration by Silver Nitrite
Azupyrene (dicyclopentaheptalene) undergoes thermal isomerization to pyrene and nitration in the 3-position by silver nitrite.
Anderson, Arthur G.,Kao, L. Glenn
p. 3589
(1982)
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Photoinduced Electron Transfer in Organized Assemblies
Photoexcitation of charge-transfer systems pyrene-dimethylaniline and pyrene-dibutylaniline has been studied in several organized assemblies, micelles, microemulsions, and vesicles.Both steady state measurements and pulse laser photolysis date show that the quenching of excited pyrene on the surface by the anilines is rapid but can be described by diffusional-type processes.Detailed mechanisms of the processes are discussed.The main products of the quenching are pyrene anions and dialkylaniline cations.Increasing the size of the assemblies, i.e., micelle to microemulsion or increasing the rigidity of the reactant's environment, i.e., micelle to vesicle, led to decreased yeilds of ions.The yeilds of ions in these latter systems can be restored if polar derivatives of pyrene are used in place of pyrene, thus locating the pyrene chromophore in the region of the assembly surface.Several reactions of the photoproduced pyrene anion were studied, as the lifetime of the anion is sufficiently long (>1 ms) to promote electron transfer between cationic ions such as Eu3+ and methyl viologen, in spite of the fact that these ions are strongly repelled by the cationic surfaces of the assemblies.It is concluded that efficient electron transfer and subsequent ion separation only occur when the rectants are located on strongly charged surfaces, where the reactants may move relatively freely, while still remaining bound to the surface.A photodiode effect is suggested to explain the efficient ion separation observed.
Atik, S.S.,Thomas, J.K.
p. 3550 - 3555
(1981)
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Dynamics for the assembly of pyrene-γ-cyclodextrin host-guest complexes
Pyrene and γ-cyclodextrin (γ-CD) form complexes with 1:1, 1:2, and 2:2 (pyrene/CD) stoichiometries. The complexation dynamics was studied using stopped flow. The dynamics for the higher-order complexes (1:2 and 2:2) occurs in the millisecond time domain, which contrasts with the much faster dynamics for the 1:1 complex. When pyrene is mixed with γ-CD, a transient enhancement of the concentration for the 2:2 complex was observed between 0.2 and 1 s, which at longer times leads to the formation of the 1:2 complex. This enhancement of the nonthermodynamic product is an example of the kinetic formation of a host-guest complex, and these types of processes may be explored to build self-assemblies under kinetic control.
Dyck, Andria S.M.,Kisiel, Ursula,Bohne, Cornelia
p. 11652 - 11659
(2003)
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Unexpected high temperature behaviour of 2,2′-diethynylbiphenyl in the gas phase - A precursor for acephenanthrylene instead of pyrene
Flash Vacuum Thermolysis (FVT) of 2,2′-diethynylbiphenyl (6) gave, instead of pyrene (5), acephenanthrylene (10) and fluoranthene (11) as major products. The unequivocal identification of 9-ethynylphenanthrene (12) at T ≤ 800°C suggests that 12 is the initial stable product derived from 6. It is documented that under high-temperature conditions in the gas phase compound 12 is efficiently converted into 10, which subsequently rearranges to 11. The formation of 12 from 6 is rationalized by invoking the transient formation of cyclobuta[l]phenanthrene (13) by intramolecular cyclization of the ethynyl moieties of 6 followed by a reiro-carbene C-H insertion and a 1,2-H shift. This interpretation is supported by the results of independent FVT of 2,2′-bis(1-chloroethenyl)biphenyl (15). Wiley-VCH Verlag GmbH, 1997.
Sarobe, Martin,Van Heerbeek, Rieko,Jenneskens, Leonardus W.,Zwikker, Jan W.
p. 2499 - 2503
(1997)
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A NEW DOUBLE BOND BRIDGED DIBENZODITHIOCIN: PREPARATION, CHARACTERIZATION, AND ITS TRANSANNULAR P?-(>S+-S+<) INTERACTION
A new heterocyclic compound, 1,11-(etheno)-5H,7H-dibenzodithiocin (1) has been prepared by treatment of mono-sulfonium salt of 1,11-(methanothiomethano)-5H,7H-dibenzodithiocin with t-BuOK in a one step; the reactivities and the transannular p?-(>S+-S+) interaction in 1 are described.
Fujihara, Hisashi,Chiu, Jer-Jye,Furukawa, Naomichi
p. 2805 - 2808
(1989)
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Regulation of one-electron oxidation rate of guanine and hole transfer rate in DNA through hydrogen bonding
The effects of methyl and bromo groups at C5 of C on the one-electron oxidation rate of G, and on the hole transfer rate in DNA have been investigated. The rates of one-electron oxidation of G and hole transfer from Py·+ to 8-oxo-7,8-dihydrogua
Kawai, Kiyohiko,Takada, Tadao,Tojo, Sachiko,Majima, Tetsuro
p. 8083 - 8085
(2002)
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Newman
p. 860
(1951)
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Rediscovering Bacon's hydrazine/phenylhydrazine mediated cyclization of 2,2′-dicarbonylbi(hetero)aryls: Construction of (5-azo)-/indazolo[2,3-: A] quinolines
Hydrazine/phenylhydrazine-mediated reductive dicarbonyl coupling reactions have been carried out under mild conditions to provide polycyclic aromatic compounds and azo-substituted polyaromatic compounds. This method has a broad substrate scope with good functional group compatibility. This journal is
Dhote, Pawan S.,Ramana, Chepuri V.
p. 636 - 648
(2022/02/01)

ORGANIC MOLECULES FOR OPTOELECTRONIC DEVICES
The invention relates to an organic molecule for optoelectronic devices. According to the invention, the organic molecule has: - a first chemical moiety with a structure of formula (I), - two second chemical moieties with a structure of formula (II), wherein X and Y are at each occurrence independently from another selected from the group consisting of B and N; Z is a direct bond; RI, RII, RIII, RIV, RV, RVI, RVII, RVIII, RIX, and RX are at each occurrence independently from another selected from the group consisting of the binding site of a single bond linking the first chemical moiety to the second moiety, and R*; R* is at each occurrence independently from another selected from the group consisting of hydrogen, deuterium, OPh, SPh, CF3, CN, F, Si(C1-C5-alkyl)3, Si(Ph)3, C1-C5-alkyl, C1-C5-alkoxy, C1-C5-thioalkoxy, C2-C5-alkenyl, C2-C5-alkynyl, C6-C18-aryl, C3-C17-heteroaryl, N(C6-C18-aryl)2, N(C3-C17-heteroaryl)2; N(C3-C17-heteroaryl)(C6-C18-aryl); and the dashed lines represent the binding sites of the first chemical moiety to the second chemical moiety.
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Page/Page column 69

(2022/03/07)

A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
Huang, Binbin,Guo, Lin,Xia, Wujiong
supporting information
p. 2095 - 2103
(2021/03/26)

Pyrene-tiaraed pillar[5]arene: Strong intramolecular excimer emission applicable for photo-writing
A pyrene-tiaraed pillar[5]arene derivative was synthesized, which showed a concentration-independent intensive excimer emission. Photolysis of the pyrene-tiaraed pillar[5]arene led to a switch from excimer to monomer emission, applicable to photo-writing.
Peng, Chao,Liang, Wenting,Ji, Jiecheng,Fan, Chunying,Kanagaraj, Kuppusamy,Wu, Wanhua,Cheng, Guo,Su, Dan,Zhong, Zhihui,Yang, Cheng
supporting information
p. 345 - 348
(2020/04/24)

Alumina-Mediated π-Activation of Alkynes
The ability to induce powerful atom-economic transformation of alkynes is the key feature of carbophilic π-Lewis acids such as gold- and platinum-based catalysts. The unique catalytic activity of these compounds in electrophilic activations of alkynes is explained through relativistic effects, enabling efficient orbital overlapping with π-systems. For this reason, it is believed that noble metals are indispensable components in the catalysis of such reactions. In this study, we report that thermally activated γ-Al2O3activates enynes, diynes, and arene-ynes in a manner enabling reactions that were typically assigned to the softest π-Lewis acids, while some were known to be triggered exclusively by gold catalysts. We demonstrate the scope of these transformations and suggest a qualitative explanation of this phenomenon based on the Dewar-Chatt-Duncanson model confirmed by density functional theory calculations.
Akhmetov, Vladimir,Amsharov, Konstantin,Feofanov, Mikhail,Sharapa, Dmitry I.
p. 15420 - 15426
(2021/09/30)

In quest of reversibility of Friedel-Crafts acyl rearrangements in the pyrene series
Friedel-Crafts acyl rearrangements in PPA of diacetylpyrenes (80–120 °C), dibenzoylpyrenes (80–200 °C), and bis(4-flurobenzoyl)pyrenes (80–120 °C) and Scholl reactions in AlCl3/NaCl of dibenzoylpyrenes (140–200 °C) have been studied. The substrates were 1-AcPY, 2-AcPY, 1,3-Ac2PY, 1,6-Ac2PY, 1,8-Ac2PY, 2,7-Ac2PY, 1-BzPY, 1,6-Bz2PY, 1,8-Bz2PY, 1-4FBzPY, 1,6-4FBz2PY, 1,8-4FBz2PY. The mixtures of pyrene, 1-AcPY, 2-AcPY, 1,3-Ac2PY, 1,6-Ac2PY, 1,8-Ac2PY, and 2,7-Ac2PY were separated by HPLC. The following reversible intermolecular isomerizations were established: 1,6-Ac2PY ? 1,8-Ac2PY, 1,6-Bz2PY ? 1,8-Bz2PY, and 1,6-4'FBz2PY ? 1,8-4'FBz2PY, albeit not in high yields. The results substantiate Gore’s 1955 proposition that “The Friedel–Crafts acylation reaction of reactive aromatic hydrocarbons is a reversible process.” The isomerizations reported here differ from the few previously reported completely reversible intramolecular Friedel-Crafts acyl rearrangements. At ≥ 140 °C, in PPA and in AlCl3/NaCl, 1,6-Bz2PY and 1,8-Bz2PY underwent a highly regioselective double Scholl reaction to give pyranthrone (3) and deacylations to 1-BzPy (and pyrene), followed by mono-Scholl reactions to give 8H-dibenzo[def,qr]chrysen-8-one (1), and 11H-indeno[2,1-a]pyren-11-one (2). The formation of 3 and not the expected tribenzo[a,ghi,o]perylene-7,16-dione (4) from 1,8-Bz2PY indicates that 1,8-Bz2PY has first undergone isomerization to 1,6-Bz2PY. The present study confirms the linkage between Friedel-Crafts acyl rearrangements and the Scholl reaction.
Agranat, Israel,Mala’bi, Tahani,Oded, Yaacov Netanel,Kraus, Hanna Daniel
p. 47 - 60
(2019/12/30)

Catalytic Reductions Without External Hydrogen Gas: Broad Scope Hydrogenations with Tetrahydroxydiboron and a Tertiary Amine
Facile reduction of aryl halides with a combination of 5% Pd/C, B2(OH)4, and 4-methylmorpholine is reported. Aryl bromides, iodides, and chlorides were efficiently reduced. Aryl dihalides containing two different halogen atoms underwent selective reduction: I over Br and Cl, and Br over Cl. Beyond these, aryl triflates were efficiently reduced. This combination was broadly general, effectuating reductions of benzylic halides and ethers, alkenes, alkynes, aldehydes, and azides, as well as for N-Cbz deprotection. A cyano group was unaffected, but a nitro group and a ketone underwent reduction to a low extent. When B2(OD)4 was used for aryl halide reduction, a significant amount of deuteriation occurred. However, H atom incorporation competed and increased in slower reactions. 4-Methylmorpholine was identified as a possible source of H atoms in this, but a combination of only 4-methylmorpholine and Pd/C did not result in reduction. Hydrogen gas has been observed to form with this reagent combination. Experiments aimed at understanding the chemistry led to the proposal of a plausible mechanism and to the identification of N,N-bis(methyl-d3)pyridin-4-amine (DMAP-d6) and B2(OD)4 as an effective combination for full aromatic deuteriation. (Figure presented.).
Korvinson, Kirill A.,Akula, Hari K.,Malinchak, Casina T.,Sebastian, Dellamol,Wei, Wei,Khandaker, Tashrique A.,Andrzejewska, Magdalena R.,Zajc, Barbara,Lakshman, Mahesh K.
supporting information
p. 166 - 176
(2020/01/02)

Mechanochemical Synthesis of N-Aryl Amides from O-Protected Hydroxamic Acids
Two robust and efficient mechanochemical protocols for the synthesis of an array of N-arylamides have been developed. This was achieved by a C?N cross-coupling between O-pivaloyl hydroxamic acids and aryl iodides or aryl boronic acids, in the presence of a stoichiometric amount of a copper mediator. The effectiveness of this method is highlighted by the high-yielding (up to 94 %), scalable (up to 8 mmol), and rapid (20 minutes) synthesis of N-aryl amides (15 examples), using a variety of deactivated and sterically encumbered substrates, whilst employing mild conditions and in the absence of solvents. In addition, it was determined that whilst the O-pivaloyl hydroxamic acid precursors can be synthesised mechanochemically, iron contamination originating from the steel jars was found to occur which can hinder the efficacy of this process. Furthermore, 3D printing was used to produce custom milling jars that could successfully accommodate a scaled-up version of the two protocols.
Broumidis, Emmanouil,Jones, Mary C.,Lloyd, Gareth O.,Vilela, Filipe
p. 1754 - 1761
(2020/09/02)

Mechanisms of Heptane Degradation and Product Formation in Microwave Discharge
Abstract: A mechanism for the degradation of n-heptane and the formation of the products of its plasma-chemical transformation by microwave discharge treatment has been proposed. Chemical reactions resulting in reactive species, namely free radicals that form lower hydrocarbons and polyaromatic structures are presented. The product composition of the gas, liquid, and solid phases has been studied using gas chromatography–mass spectrometry analysis of the precipitate obtained by evaporation of the liquid phase after the treatment of n-heptane.
Bobkova,Stokolos,Garifullin
p. 336 - 340
(2019/08/15)

Palladium-metalated porous organic polymers as recyclable catalysts for chemoselective decarbonylation of aldehydes
A novel palladium nanoparticle (NP)-metalated porous organic ligand (Pd NPs/POL-xantphos) has been prepared for the chemoselective decarbonylation of aldehydes. This heterogenous catalyst not only has excellent catalytic activity and chemoselectivity, but also holds high activity after 10 runs of reuse. The effective usage of this method is demonstrated through the synthesis of biofuels such as furfuryl alcohol (FFA) via the highly chemoselective decarbonylation of biomass-derived 5-hydroxy-methylfurfural (HMF) with a TON up to 1540. More importantly, 9-fluorenone could be obtained in one step through the decarbonylation of 2-bromobenzaldehyde by using this heterogeneous catalyst.
Li, Wen-Hao,Li, Cun-Yao,Li, Yan,Tang, Hai-Tao,Wang, Heng-Shan,Pan, Ying-Ming,Ding, Yun-Jie
supporting information
p. 8446 - 8449
(2018/08/28)

Regioselective Synthesis of 2- or 2,7-Functionalized Pyrenes via Migration
A simple method for the preparation of 2- or 2,7-functional pyrenes from 1- or 1,6-substituted derivatives is reported. The synthesis involves the unexpected 1,2-phosphinyl migration in an AlCl3/NaCl melt. The structure of the product has been unambiguously confirmed by X-ray crystallography. We also demonstrated that further functionalization of pyrene through C-P bond activation is possible. These 2,7-positions are difficult to derivatize otherwise.
Qiu, Liqi,Hu, Wei,Wu, Di,Duan, Zheng,Mathey, Francois
supporting information
p. 7821 - 7824
(2019/01/14)

Polycyclic Aromatic Hydrocarbons via Iron(III)-Catalyzed Carbonyl-Olefin Metathesis
Polycyclic aromatic hydrocarbons are important structural motifs in organic chemistry, pharmaceutical chemistry, and materials science. The development of a new synthetic strategy toward these compounds is described based on the design principle of iron(III)-catalyzed carbonyl-olefin metathesis reactions. This approach is characterized by its operational simplicity, high functional group compatibility, and regioselectivity while relying on FeCl3 as an environmentally benign, earth-abundant metal catalyst. Experimental evidence for oxetanes as reactive intermediates in the catalytic carbonyl-olefin ring-closing metathesis has been obtained.
McAtee, Christopher C.,Riehl, Paul S.,Schindler, Corinna S.
p. 2960 - 2963
(2017/03/11)

Nickel-Catalyzed Deamidative Step-Down Reduction of Amides to Aromatic Hydrocarbons
To date, cleavage of the C-N bond in aromatic amides has been achieved in molecules with a distorted constitutional framework around the nitrogen atom. In this report, a nickel-catalyzed reduction of planar amides to the corresponding lower hydrocarbon homologue has been reported. This involves a one-pot reductive cleavage of the C-N bond followed by a tandem C-CO bond break in the presence of a hydride source. Substrate scope circumscribes deamidation examples which proceed via oxidative addition of nickel in the amide bonds of nontwisted amides. Mechanistic studies involving isolation and characterization of involved intermediates via different spectroscopic techniques reveal a deeper introspection into the plausible catalytic cycle for the methodology.
Dey, Aniruddha,Sasmal, Sheuli,Seth, Kapileswar,Lahiri, Goutam Kumar,Maiti, Debabrata
p. 433 - 437
(2017/06/05)

Nickel-catalyzed reductive defunctionalization of esters and amides to aromatic hydrocarbons
The removal of ester and amide groups is of fundamental significance in organic syntheses. Under non-catalytic conditions, hydride sources are chiefly used for their reduction. Recently developed Ni-catalyzed one-pot reductive activation of esters and ami
Mondal, Manoj,Bharali, Pankaj
p. 13211 - 13214
(2017/11/27)

The synthesis and STM/AFM imaging of 'Olympicene' benzo[cd]pyrenes
H-Benzo[cd ]pyrene ('Olympicene') is a polyaromatic hydrocarbon and non-Kekul fragment of graphene. A new synthetic method has been developed for the formation of 6H-benzo[cd]pyrene and related ketones including the first time isolation of the unstable alcohol 6H-benzo[cd]pyren-6-ol. Molecular imaging of the reaction products with scanning tunnelling microscopy (STM) and non-contact atomic force microscopy (NC-AFM) characterised the 6H-benzo[cd]pyrene as well as the previously intangible and significantly less stable 5 H-benzo[cd ]pyrene, the fully conjugated benzo[cd]pyrenyl radical and the ketones as oxidation products.
Mistry, Anish,Moreton, Ben,Schuler, Bruno,Mohn, Fabian,Meyer, Gerhard,Gross, Leo,Williams, Antony,Scott, Peter,Costantini, Giovanni,Fox, David J.
supporting information
p. 2011 - 2018
(2015/01/30)

Single label comparative hybridization
The present invention provides methods of detecting and mapping chromosomal or genetic abnormalities associated with various diseases or with predisposition to various diseases, or to detecting the phenomena of large scale copy number variants. In particular, the present invention provides advanced methods of performing array-based comparative hybridization that allow reproducibility between samples and enhanced sensitivity by using the same detectable label for both test sample and reference sample nucleic acids. Invention methods are useful for the detection or diagnosis of particular disease conditions such as cancer, and detecting predisposition to cancer based on detection of chromosomal or genetic abnormalities and gene expression level. Invention methods are also useful for the detection or diagnosis of hereditary genetic disorders or predisposition thereto, especially in prenatal samples. Moreover, invention methods are also useful for the detection or diagnosis of de novo genetic aberrations associated with post-natal developmental abnormalities.
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(2015/01/06)

An efficient dehydroxymethylation reaction by a palladium catalyst
A general method for selective dehydroxymethylation has been discovered by using widely available Pd(OAc)2. The present study offers a new synthetic strategy for the regioselective functionalization by employing the steric, electronic and coordinating nature of the hydroxymethyl (-CH 2OH) group temporarily.
Modak, Atanu,Naveen, Togati,Maiti, Debabrata
supporting information
p. 252 - 254
(2013/02/22)

Synthesis of SAPO-35 molecular sieve and its catalytic properties in the methanol-to-olefins reaction
SAPO-35 molecular sieve samples with different Si contents were hydrothermally synthesized using hexamethyleneimine as the template and characterized by XRD, XRF, SEM, MAS NMR, XPS and N2 physisorption. Three SAPO-35 samples were tested as methanol-to-olefins catalysts. After the reaction, the evolution of coke species was investigated over SAPO-35 and SAPO-34 catalysts with similar Si concentrations. A correlation between the cage size of the molecular sieves and the coke species was obtained.
Li, Bing,Tian, Peng,Li, Jinzhe,Chen, Jingrun,Yuan, Yangyang,Su, Xiong,Fan, Dong,Wei, Yingxu,Qi, Yue,Liu, Zhongmin
p. 798 - 807
(2013/07/25)

MCR DENDRIMERS
The invention relates to a method for producing peptoidic, peptidic and chimeric peptidic-peptoidic dendrimers by multiple iterative multi-component reactions (MCR), in particular Ugi or Passerini multi-component reactions, to compounds produced in this way and to the use thereof.
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(2013/08/15)

Pyrolytic formation of polycyclic aromatic hydrocarbons from sesquiterpenes
The products of the pyrolysis of four sesquiterpenes, β-caryophyllene, α-cedrene, longifolene and valencene, have been examined. Pyrolysis was carried out at 300, 400 and 500 °C, the products determined by GC-MS and then examined for similarities and diff
Francis, George W.,Christy, Alfred A.,Oygarden, Jostein
p. 1316 - 1322
(2012/11/06)

A general and efficient aldehyde decarbonylation reaction by using a palladium catalyst
A facile decarbonylation reaction of aldehydes has been developed by employing Pd(OAc)2. A wide variety of substrates are decarbonylated, without using any exogenous ligand for palladium as well as CO-scavenger.
Modak, Atanu,Deb, Arghya,Patra, Tuhin,Rana, Sujoy,Maity, Soham,Maiti, Debabrata
supporting information; experimental part
p. 4253 - 4255
(2012/05/04)

Microwave-assisted palladium mediated decarbonylation reaction: Synthesis of eulatachromene
Microwave-assisted decarbonylation reactions were investigated using a palladium catalyst. A large number of aldehydes can be decarbonylated efficiently with lower catalyst loadings and under shorter reaction times compared to conventional heating. A successful decarbonylation led to the synthesis of natural product eulatachromene in three steps starting from easily available materials.
Akanksha,Maiti, Debabrata
experimental part
p. 2314 - 2320
(2012/09/21)

Nucleic acid size detection method
The present invention provides methods of determining the size of a particular nucleic acid segment of interest in a sample of nucleic acids through fragmentation of DNA, size fractionation, an optional second fragmentation, and identification using a marker sequence. In particular aspects, an expansion or reduction of tandem repeat sequences can be detected. In further aspects, carriers and individuals afflicted with fragile X syndrome or other diseases associated with tandem repeats can be distinguished from normal individuals.
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(2012/05/04)

Synthesis of uniformly 13C-labeled polycyclic aromatic hydrocarbons
Convergent synthetic pathways were devised for efficient synthesis of a series of uniformly 13C labeled polycyclic aromatic hydrocarbons de novo from U-13C-benzene and other simple commercially-available 13C-starting compounds. All target products were obtained in excellent yields, including the alternant PAH U-13C-naphthalene, U-13C-phenanthrene, U-13C-anthracene, U- 13C-benz[a]anthracene, U-13C-pyrene and the nonalternant PAH U-13C-fluoranthene.
Zhang, Zhenfa,Sangaiah, Ramiah,Gold, Avram,Ball, Louise M.
experimental part
p. 5431 - 5435
(2011/09/14)

Synthesis of pyrenes by twofold hydroarylation of 2,6-dialkynylbiphenyls
Cationic gold(I) complexes having Buchwald-type biarylphosphines effectively catalyzed twofold hydroarylation of 2,6-dialkynylbiphenyls to construct pyrene skeletons.
Matsuda, Takanori,Moriya, Taisaku,Goya, Tsuyoshi,Murakami, Masahiro
p. 40 - 41
(2011/05/07)

Assay for mycobacterium avium/intracellulare nucleic acid
Disclosed is a method for determining the presence of Mycobacterium avium complex nucleic acids in a biological sample. In particular, the mig gene of M. avium and the DT1 gene of M. intracellulare are detected, preferably following amplification. In addition, the method distinguishes between species of M. avium and M. intracellulare. Also described are oligonucleotides that can be used as primers to amplify target genes such as mig and DT1 genes and as probes as well as kits containing the oligonucleotides.
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(2010/12/26)

Substractive single label comparative hybridization
Provided are methods of determining differences between nucleic acids in a test sample and a reference sample. In certain embodiments the methods are used for detecting and mapping chromosomal or genetic abnormalities associated with various diseases or with predisposition to various diseases, or to detecting the phenomena of large scale copy number variants. In particular, provided are advanced methods of performing array-based comparative hybridization that allow reproducibility between samples and enhanced sensitivity by using the same detectable label for both test sample and reference sample nucleic acids. Invention methods are useful for the detection or diagnosis of particular disease conditions such as cancer, and detecting predisposition to cancer based on detection of chromosomal or genetic abnormalities and gene expression level. Invention methods are also useful for the detection or diagnosis of hereditary genetic disorders or predisposition thereto, especially in prenatal samples. Moreover, invention methods are also useful for the detection or diagnosis of de novo genetic aberrations associated with post-natal developmental abnormalities.
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(2009/04/24)

Facile photochemical transformation of alkyl aryl selenides to the corresponding carbonyl compounds by molecular oxygen: Use of selenides as masked carbonyl groups
(Chemical Equation Presented) Alkyl aryl selenides with and without functional groups on the alkyl group were transformed efficiently into the corresponding carbonyl compounds, particulary primary alkyl aryl selenides in good yields, by a simple photolysis in the presence of air or oxygen. This transformation can be conducted without protection of functional groups. The yield of carbonyl compounds was much affected by the solvent viscosity, reaction temperature, concentration of dissolved oxygen in the solvents, wavelength of light, and structure of the aryl substituents. The present study indicates that aryl selenides can be considered as a masked carbonyl group that can be easily converted to a carbonyl group by very mild reaction conditions even in the presence of various unprotected functional groups. Therefore, this functional group transformation can be used as an important tool in organic synthesis due to its simplicity and mild reaction condition.
Hyugano, Takeshi,Liu, Suyou,Ouchi, Akihiko
supporting information; body text
p. 8861 - 8866
(2009/04/05)

Detailed chemical kinetic modeling of pyrolysis of ethylene, acetylene, and propylene at 1073-1373 K with a plug-flow reactor model
This study examines the predictive capability of our recently proposed reaction mechanism (Norinaga and Deutschmann, Ind Eng Chem Res 2007, 46, 3547) for hydrocarbon pyrolysis at varying temperature. The conventional flow reactor experiments were conducted at 8 kPa, over the temperature range 1073-1373 K, using ethylene, acetylene, and propylene as reactants to validate the mechanism. More than 40 compounds were identified and quantitatively analyzed by on- and off-line gas chromatography. The chemical reaction schemes consisting of 227 species and 827 reactions were coupled with a plug-flow reactor model that incorporated the experimentally measured axial temperature profile of the reactor. Comparisons between the computations and the experiments are presented for more than 30 products including hydrogen and hydrocarbons ranging from methane to coronene as a function of temperature. The model can predict the compositions of major products (mole fractions larger than 10-2) in the pyrolysis of three hydrocarbons with satisfactory accuracies over the whole temperature range considered. Mole fraction profiles of minor compounds including polycyclic aromatic hydrocarbons (PAHs) up to three ring systems, such as phenanthrene, anthracene, and phenylnaphthalene, are also fairly modeled. At temperatures lower than 1273 K, larger PAHs were underpredicted and the deviation became larger with decreasing temperature and increasing molecular mass of PAHs, while better agreements were found at temperatures higher than 1323 K.
Norinaga, Koyo,Janardhanan, Vinod M.,Deutschmann, Olaf
p. 199 - 208
(2008/09/18)

Role of temperature and hydrochloric acid on the formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons during combustion of paraffin powder, polymers, and newspaper
Formation of chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were determined using a laboratory-scale incinerator when combusting materials at different temperatures, different concentrations of hydrochloric acid (HCl), and when combusting various types of polymers/newspaper. Polychlorobenzenes (PCBz), polychlorophenols (PCPhs), polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and their toxic equivalency (TEQ) and PAHs were highlighted and reported. Our results imply maximum formation of chlorinated hydrocarbons at 400°C in the following order; PCBz≥PCPhs?PCDFs>PCDDs>TEQ on a parts-per-billion level. Similarly, a maximum concentration of chlorinated hydrocarbons was noticed with an HCl concentration at 1000 ppm with the presence of paraffin powder in the following order; PAHs>PCBz≥PCPhs?PCDFs>PCDDs>TEQ an a parts-per-billion level. PAHs were not measured at different temperatures. Elevated PAHs were noticed with different HCl concentrations and paraffin powder combustion (range: 27-32 μg/g). While, different polymers and newspaper combusted, nylon and acrylonitrile butadiene styrene (ABS) produced the maximum hydrogen cyanide (HCN) concentration, concentrations of PCDD/FS, dioxin-like polychlorinated biphenyls (DL-PCBs), and TEQ were in a decreasing order: polyvinylchloride (PVC)newspaperpolyethyleneterephthalate (PET) polyethylene (PE) polypropylene (PP) ABS = blank. Precursors of PCBs were in a decreasing order: PPnylonPEnewspaperABSPVCblankPET. Precursors of PCDD/Fs were in a decreasing order: newspaper PP= nylonPEABSPVC= blankPET. BTX formation was in a decreasing order; PEnylonnewspaperABSPP. PAHs formation were elevated with parts-per-million levels in the decreasing order of PPnylonPE newspaperblankABS PETPVC.
Takasuga, Takumi,Umetsu, Norihito,Makino, Tetsuya,Tsubota, Katsuya,Sajwan, Kenneth S.,Kumar, Kurunthachalam Senthil
p. 8 - 21
(2008/02/09)

Emission factors for carbonaceous particles and polycyclic aromatic hydrocarbons from residential coal combustion in China
Emission factors of carbonaceous particles, including black carbon (BC) and organic carbon (OC), and polycyclic aromatic hydrocarbons (PAHs) were determined for five coals, which ranged in maturity from sub-bituminous to anthracite. They were burned in the form of honeycomb briquettes in a residential coalstove, one of the most common fuel/stove combinations in China. Smoke samples were taken through dilution sampling equipment, with a high volume sampler that could simultaneously collect emissions in both particulate and gaseous phases, and a cascade impactor that could segregate particles into six fractions. Particulate BC and OC were analyzed by a thermal-optical method, and PAHs in emissions of both phases were analyzed by GC-MS. Burning of bituminous coals produced the highest emission factors of particulate matter (12.91 g/kg), BC (0.28 g/kg), OC (7.82 g/kg), and 20 PAHs (210.6 mg/kg) on the basis of burned dry ash-free (daf) coal, while the anthracite honeycomb-briquette was the cleanest household coal fuel. The size-segregated results show that more than 94% of the particles were submicron, and calculated mass median aerodynamic diameters (MMAD) of all particles were under 0.3 μm. Based on the coal consumption in the residential sector of China, 290.24 Gg (gigagrams) of particulate matter, 5.36 Gg of BC, 170.33 Gg of OC, and 4.72 Gg of 20 PAHs mass were emitted annually from household honeycomb-briquette burning during 2000. Anthracite coal should be selected preferentially and more advanced burning conditions should be applied in domestic combustion, from the viewpoint of both climate change and adverse health effects.
Chen, Yingjun,Sheng, Guoying,Bi, Xinhui,Feng, Yanli,Mai, Bixian,Fu, Jiamo
p. 1861 - 1867
(2008/12/21)

Emission factors and importance of PCDD/Fs, PCBs, PCNs, PAHs and PM 10 from the domestic burning of coal and wood in the U.K.
This paper presents emission factors (EFs) derived for a range of persistent organic pollutants (POPs) when coal and wood were subject to controlled burning experiments, designed to simulate domestic burning for space heating. A wide range of POPs were emitted, with emissions from coal being higher than those from wood. Highest EFs were obtained for particulate matter, PM10, (～ 10 g/kg fuel) and polycyclic aromatic hydrocarbons (～ 100 mg/ kg fuel for ΣPAHs). For chlorinated compounds, EFs were highest for polychlorinated biphenyls (PCBs), with polychlorinated naphthalenes (PCNs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) being less abundant. EFs were on the order of 1000 ng/kg fuel for ΣPCBs, 100s ng/ kg fuel for ΣPCNs and 100 ng/kg fuel for ΣPCDD/Fs. The study confirmed that mono- to trichlorinated dibenzofurans, Cl1,2,3DFs, were strong indicators of low temperature combustion processes, such as the domestic burning of coal and wood. It is concluded that numerous PCB and PCN congeners are routinely formed during the combustion of solid fuels. However, their combined emissions from the domestic burning of coal and wood would contribute only a few percent to annual U.K. emission estimates. Emissions of PAHs and PM 10 were major contributors to U.K. national emission inventories. Major emissions were found from the domestic burning for Cl1,2,3DFs, while the contribution of PCDD/F-ΣTEQ to total U.K. emissions was minor.
Lee, Robert G. M.,Coleman, Peter,Jones, Joanne L.,Jones, Kevin C.,Lohmann, Rainer
p. 1436 - 1447
(2007/10/03)

Experimental study on the removal of PAHs using in-duct activated carbon injection
This paper presents the incineration tests of municipal solid waste (MSW) in a fluidized bed and the adsorption of activated carbon (AC) on polycyclic aromatic hydrocarbons (PAHs). An extraction and high performance liquid chromatography (HPLC) technique was used to analyze the concentrations of the 16 US EPA specified PAHs contained in raw MSW, flue gas, fly ash, and bottom ash. The aim of this work was to decide the influence of AC on the distribution of PAHs during the incineration of MSW. Experimental researches show that there were a few PAHs in MSW and bottom ash. With the increase of AC feeding rate, the concentrations of three- to six-ring PAHs in fly ash increased, and the concentration of two-ring PAH decreased. The total-PAHs in flue gas were dominated by three-, and four-ring PAHs, but a few two-, five-ring PAHs and no six-ring PAHs were found. PAHs could be removed effectively from flue gas by using in-duct AC injection and the removal efficiencies of PAHs were about 76-91%. In addition, the total toxic equivalent (TEQ) concentrations of PAH in raw MSW, bottom ash, fly ash, and flue gas were 1.24 mg TEQ kg-1, 0.25 mg TEQ kg-1, 6.89-9.67 mg TEQ kg-1, and 0.36-1.50 μg TEQ N m-3, respectively.
Zhou, Hong-Cang,Zhong, Zhao-Ping,Jin, Bao-Sheng,Huang, Ya-Ji,Xiao, Rui
p. 861 - 869
(2007/10/03)

Oligonucleotides comprising a molecular switch
This invention relates to oligonucleotides comprising a molecular switch which may exist in an “open” or “closed” position. The molecular switch portion of the probe is particularly sensitive to the identity of sequences complementary to the molecular switch. Oligonucleotides containing a molecular switch are applicable to all kinds of hybridization processes. Due to the sensitivity of the switch domain of the oligonucleotide, probes containing a molecular switch are particularly useful in the identification of single point mismatches. More specifically, a portion, but not all, of the oligonucleotide becomes unbound from a mismatched target. The invention further relates to methods of using said oligonucleotides for research reagents, and clinical diagnostics. An exemplary oligonucleotide comprises a first hybridizable domain, a second bridging block domain, and a third binding domain.
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(2008/06/13)

Activatable probes and methods for in vivo gene detection
Probes for detecting a target polynucleotide are provided. One aspect provides a molecular beacon probe set wherein the donor molecular beacon comprises a quantum dot and an acceptor molecular beacon comprises at least one reporter. The probes optionally comprise a protein transduction domain, targeting signal, or a combination thereof. Methods for detecting target polynucleotides using the disclosed probes are also provided.
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(2008/06/13)

Complete study of the pyrolysis and gasification of scrap tires in a pilot plant reactor
The pyrolysis and gasification of tires was investigated in a pilot plant reactor provided with a system for condensation of semivolatile matter. The study comprised experiments at 450°, 750°, and 1000°C both in nitrogen and 10% oxygen atmospheres. In the gas phase, only methane and benzene yields increased with temperature until 1000°C. In the liquids, the main components were styrene, limonene, and isoprene. The solid fraction (including soot) increased with temperature. Zinc content of the char decreased with increasing temperature. Analysis of the surface area of the solids showed that the area was similar in all cases to that of a commercial carbon black. The higher surface of the soot with respect to the chars was observed. The results coincided with published findings, i.e., kinetic severity function values would produce 0.2% of methane at 450°C and 4.5% at 750°-1000°C.
Conesa, Juan A.,Martin-Gullon,Font,Jauhiainen
p. 3189 - 3194
(2008/12/21)

Semivolatile and volatile compounds in combustion of polyethylene
The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
p. 615 - 627
(2007/10/03)

Relationship between pressure fluctuations and generation of organic pollutants with different particle size distributions in a fluidized bed incinerator
The hydrodynamic behaviors of fluidization perhaps significantly influence the uniformity of fluidization in fluidized bed incinerator. Good uniformity of fluidization expressed the air across uniformly through the bed and the particles being distributed well in the fluid stream. The aggregates, flocs and channels of particles do not happen during fluidization. The Good uniformity will maintain high heat and mass distribution to improve reaction efficiency. These parameters include the height of static bed, gas velocity, mixing and distribution of bed particle, which have rarely been studied in previous investigations. Consequently, this study examines how the hydrodynamic parameters affect the generation of organic pollutants (BTEXs and PAHs) during incineration. The statistical and power spectral analysis of the measured pressure fluctuation during incineration are used to elucidate the relationship between behaviors of fluidization and generation of pollutants during incineration. Experimental results show the organic concentration does not increase with uniformity of fluidization decreasing. The reason may be the explosion of the gas and the consequent thermal shock destroy the coalescent bubbles to form small bubbles again and enhance the efficiency of transfer of oxygen to increase combustion efficiency. Additionally, the mean amplitude and fluidized index of pressure fluctuation similarly vary with the concentration of organic pollutants. These two indices can be used to assess the efficiency of combustion. The four particle size distributions could be divided into two groups by statistical analysis. The Gaussian and narrow distributions belong to one group and the binary and flat the other. The organic concentration of the Gaussian and narrow distributions are lower than that of the other distributions. Consequently, the bed materials should maintain narrow or Gaussian distributions to maintain a good combustion efficiency during incineration.
Lin, Chiou-Liang,Wey, Ming-Yen,Cheng, Han-Tsung
p. 911 - 922
(2007/10/03)

Dual resonance energy transfer nucleic acid probes
Dual nucleic acid probes with resonance energy transfer moieties are provided. In particular, fluorescent or luminescent resonance energy transfer moieties are provided on hairpin stem-loop molecular beacon probes that hybridize sufficiently near each other on a subject nucleic acid, e.g. mRNA, to generate an observable interaction. The invention also provides lanthanide chelate luminescent resonance energy transfer moieties on linear and stem-loop probes that hybridize sufficiently near each other on a subject nucleic acid to generate an observable interaction. The invention thereby provides detectable signals for rapid, specific and sensitive hybridization determination in vivo. The probes are used in methods of detection of nucleic acid target hybridization for the identification and quantification of tissue and cell-specific gene expression levels, including response to external stimuli, such as drug candidates, and genetic variations associated with disease, such as cancer.
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(2008/06/13)

Condensed eight-ring aromatic compounds, organic EL element and organic EL display using the same
The object of the present invention is to provide an organic EL element which utilizes a novel condensed eight-ring aromatic compound, and has high color purity of red light and excellent light-emitting efficiency, light-emitting luminance and the like. The organic EL element of the present invention has, in between a positive electrode and a negative electrode, an organic thin-film layer including a light-emitting layer. The organic thin-film layer contains the condensed eight-ring aromatic compound which has 14, 16 or 18 regions where substituents can be introduced and a point-symmetrical carbon skeleton.
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(2008/06/13)