- A new and potentially prebiotic α-cytidine derivative
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A new α-cytidine derivative was synthesised from the prebiotic reaction of ribose aminooxazoline and dicyanoacetylene. The tetracyclic structure of the product was confirmed by X-ray diffraction and then an alternative 6-step synthetic pathway to the product was found which was suitable for large-scale synthesis.
- Tsanakopoulou, Maria,Xu, Jianfeng,Bond, Andrew D.,Sutherland, John D.
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- From Linear Molecular Chains to Extended Polycyclic Networks: Polymerization of Dicyanoacetylene
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Dicyanoacetylene (C4N2) is an unusual energetic molecule with alternating triple and single bonds (think miniature, nitrogen-capped carbyne), which represents an interesting starting point for the transformation into extended carbon-nitrogen solids. While pressure-induced polymerization has been documented for a wide variety of related molecular solids, precise mechanistic details of reaction pathways are often poorly understood and the characterization of recovered products is typically incomplete. Here, we study the high-pressure behavior of C4N2 and demonstrate polymerization into a disordered carbon-nitrogen network that is recoverable to ambient conditions. The reaction proceeds via activation of linear molecules into buckled molecular chains, which spontaneously assemble into a polycyclic network that lacks long-range order. The recovered product was characterized using a variety of optical spectroscopies, X-ray methods, and theoretical simulations and is described as a predominately sp2 network comprising "pyrrolic" and "pyridinic" rings with an overall tendency toward a two-dimensional structure. This understanding offers valuable mechanistic insights into design guidelines for next-generation carbon nitride materials with unique structures and compositions.
- Gou, Huiyang,Zhu, Li,Huang, Haw-Tyng,Biswas, Arani,Keefer, Derek W.,Chaloux, Brian L.,Prescher, Clemens,Yang, Liuxiang,Kim, Duck Young,Ward, Matthew D.,Lerach, Jordan,Wang, Shengnan,Oganov, Artem R.,Epshteyn, Albert,Badding, John V.,Strobel, Timothy A.
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- Vibrational infrared and Raman spectra of dicyanoacetylene
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The Raman and infrared spectra for solid C4N2 are reported.New assignments are given for ν1 (2333 cm-1), ν2 (2267) and ν3 (640 cm-1).These assignments are supported by a Normal Coordinate Analysis using eight force constants.Extinction coefficients for the infrared active fundamentals are also reported.Our results suggest C4N2 to be a likely candidate to explain the 478 cm-1 band in the Titan's emission recorded by the Voyager mission.
- Khanna, R. K.,Perera-Jarmer, M. A.,Ospina, M. J.
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- Reaction rates of the CN radical with diacetylene and dicyanoacetylene
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Rates of CN reactions with diacetylene (DA) and dicyanoacetylene (DCA) have been measured at room temperature from the decay of the CN radical at various sample pressures by laser induced fluorescence. The rate constants are (4.2 ± 0.2) × 10-10 and (5.4±0.2) × 10-13 in units of cm3 molec-1 s-1 for DA and DCA, respectively, which follow the general pattern of CN reactions with hydrocarbons and nitriles. In the lower temperature circumstellar envelopes and Titan's atmosphere, the CN reaction with C4H2 may be more important, while the reaction with C4N2 may become less important.
- Seki, Kanekazu,Yagi, Mikio,He, Maoqi,Halpern, Joshua B.,Okabe, Hideo
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- Organic Heterocyclothiazenes. Part 5. Cycloaddition Reactions of Tetrasulphur Tetranitride with Highly Electron Deficient Alkynes
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In contrast with previous, complex, S4N4-alkyne reactions, treatment of butynedinitrile and S4N4 is found to give 1,3,5,2,4-trithiadiazepine-6,7-dicarbonitrile (8) and 1,2,5-thiadiazole-3,4-dicarbonitrile (9) very cleanly and in high yield.Hexafluorobut-2
- Dunn, Peter J.,Rees, Charles W.
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- Gas infrared spectra, assignments, and absolute IR band intensities of C4N2 in the 250-3500 cm-1 region: Implications for Titan's stratosphere
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The IR spectrum of gaseous dicyanoacetylene, NC-C≡CC-CN, is studied in the 3500-220 cm-1 range, employing Fourier transform spectroscopy. A total of 17 bands are analyzed and assigned. The absolute intensity is determined and the associated uncertainty is estimated for each of the bands. The resulting data are used to study the detectability of gaseous C4N2 in Titan's atmosphere. In particular a better estimate of the upper limits of its abundance in Titan's atmosphere is obtained when our results are used to reanalyse Voyager IRIS infrared spectra.
- Khlifi,Paillous,Bruston,Guillemin,Benilan,Daoudi,Raulin
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- The infrared and Raman spectrum of dicyanoacetylene. The ν9 fundamental
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The Raman spectrum of liquid dicyanoacetylene, NC-CC-CN, was reinvestigated and ν3 found at 617 cm-1.The Fermi resonance between ν1 and 2ν5 is explained, considering the isotopic species NC-13CC-CN.The high resolution infrared spectrum of the lowest frequency fundamental ν9 has been recorded for the first time, and the rotational constants for several states with v9 /= 9 have been determied.
- Winther, F.,Ketelsen, M.,Guarnieri, A.
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- Compound and method of producing organic semiconductor device
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A method of producing an organic semiconductor device is provided in which a layer composed of an organic semiconductor having excellent crystallinity and orientation in a low-temperature region can be formed, and the device can be produced in the air. The method includes forming a layer composed of an organic semiconductor precursor on a base body and irradiating the organic semiconductor precursor with light, wherein the organic semiconductor precursor is a porphyrin compound or an azaporphyrin compound having in its molecule at least one of the structure represented by the following general formula (1) or (2):
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Page/Page column 82
(2011/04/26)
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- NOVEL COMPOUND AND METHOD OF PRODUCING ORGANIC SEMICONDUCTOR DEVICE
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A method of producing an organic semiconductor device is provided in which a layer composed of an organic semiconductor having excellent crystallinity and orientation in a low-temperature region can be formed, and the device can be produced in the air. The method includes forming a layer composed of an organic semiconductor precursor on a base body and irradiating the organic semiconductor precursor with light, wherein the organic semiconductor precursor is a porphyrin compound or an azaporphyrin compound having in its molecule at least one of the structure represented by the following general formula (1) or (2):
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- NIR chromophores from small acetylenic building blocks: A Diels-Alder approach to octaalkynylphthalocyanines
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Two new routes to cross-conjugated 3,4-dimethylenehexa-1,5-diynes, both starting from dialkynyl 1,2-diones, have been devised. Whereas triisopropylsilyl-protected diketones could be diolefinated in a bis-Wittig reaction with methylenetriphenylphosphorane, their aryl-terminated congeners had to be subjected to the conditions of the Peterson olefination (trimethylsilylmethylmagnesium chloride and subsequent dehydration of the resulting diol with thionyl chloride). The reactivity of the diethynylbutadienes towards standard dienophiles was found to be low and alternative thermal reactions compete with [4 + 2] cycloadditions. However, dicyanoacetylene was shown to be an effective cycloaddition partner leading, after aromatisation, to the corresponding dicyanodiethyriylbenzenes. These were cyclotetramerised with magnesium butanolate in butanol to furnish octaalkynylphthalocyanines, thereby completing a concise, three-step synthesis of these NIR chromophores of relevance to photodynamic forms of therapy. The Royal Society of Chemistry 2000.
- Faust, Ruediger,Mitzel, Frieder
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p. 3746 - 3751
(2007/10/03)
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- Photochemistry of cyanoacetylene at 193.3 nm
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Cyanoacetylene (CA) is an important minor constituent in the Titan atmosphere and is present in the interstellar medium. The absorption cross section of CA has been measured in the region from 190 to 255 nm with a resolution of 1 nm. The photochemistry of CA at 193.3 nm has been studied using a quadrupole mass spectrometer and a Fourier transform infrared spectrometer for product analysis. From the photolysis of HC3N-D2 and HC3N-CD4 mixtures and a plateau value of 0.3 for the quantum yield (QY) of DC3N (C3N + D2 → DC3N + D), it is concluded that the main dissociation process is HC3N + hv → H + C3N with a QY of 0.30 ± 0.05 and a minor process is HC3N + hv → C2H + CN with a QY equal to or less than 0.02. The remaining process is the formation of metastable CA (a triplet or carbene). The photolysis of CA induces a noticeable pressure decrease and a concomitant formation of a mist. The QY of CA disappearance is 4.5 ± 0.5, which is much higher than that of diacetylene (QY = 2.0 ± 0.5) and of acetylene (QY = 2.3). The rapid mist formation in CA may explain a haze observed in the Titan atmosphere. A detailed mist formation process is not known. The C3N radical disappears partially by C3N + HC3N → C6N2 + H and 2C3N → C6N2. To explain the formation of minor products, HCN, C2H2, HC5N, and C4N2, two processes involving an unspecified CA metastable state or states may be proposed: HC3N* + HC3N → HC5N + HCN and C4N2 + C2H2.
- Seki, Kanekazu,He, Maoqi,Liu, Renzhang,Okabe, Hideo
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p. 5349 - 5353
(2007/10/03)
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- REACTOR FOR SYNTHESIS OF DICYANOACETYLENE BY DEHYDRATION OF ACETYLENEDICARBOXAMIDE WITH PHOSPHORIC ANHYDRIDE, OPERATING IN STEADY-STATE SELF-PROPAGATING THERMAL WAVE MODE
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Using a previously proposed model of heat propagation in a reaction mixture of acetylenedicarboxamide with phosphoric anhydride for the synthesis of dicyanoacetylene in the mode of a steady-state self-propagating thermal wave and also previously obtained experimental data, we have proposed a configuration and calculated thermal operation modes of a commercial reactor for dicyanoacetylene synthesis.
- Alekseev, Yu. I.,Korolev, V. L.,Pashkevich, D. S.
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p. 1604 - 1607
(2007/10/03)
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- EXPERIMENTAL STUDY OF THE SYNTHESIS OF DICYANOACETYLENE BY DEHYDRATION OF ACETYLENEDICARBOXAMIDE WITH PHOSPHORIC ANHYDRIDE IN THE MODE OF A SELF-PROPAGATING STATIONARY HEAT WAVE
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The feasibility of ensuring a wave mode of heat propagation in the mixture of acetylenedicarboxamide (ADCA) and phosphoric anhydride has been experimentally shown.The limiting concentrations of ADCA, restricting the occurrence range of the wave process, have been found.The yields of dicyanoacetylene and by-products obtained in the wave process have been determined as functions of the concentration of ADCA and initial temperature of the reaction mixture.
- Alekseev, Yu. I.,Pashkevich, D. S.
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p. 1794 - 1797
(2007/10/02)
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