Cyanoacetylenic complexes as pre-reactional species leading to the HC7N synthesis. Part II: Experimental and theoretical identifications of the HC5N:C2H2 complex

Couturier-Tamburelli, Isabelle; Sessouma, Bintou; Coupeaud, Anne; Aycard, Jean‐Pierre; Piétri, Nathalie

doi:10.1016/j.chemphys.2008.11.020

Cited by 7 publications

(2 citation statements)

References 21 publications

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“…[12] Going beyond at riple-zeta basis set for optimizations including Br derivatives at the CCSD(T) becomes practically prohibited, so we decided to explore the effect of enlarging the basis set expansion from at riple-to aq uintuplezeta level by using the B3LYP method, which combines the nonlocal correlation function of Lee et al [8b] with the Becke's three-parameter non-local hybrid exchange functional. [8a] The B3LYP theoretical model was also found to provide reliable structures and vibrational frequencies for the types of systems investigated in this paper, [13] and for closely related compounds. [11a, 14] Hence, the geometry of BrC 5 Nw as optimized at the B3LYP/cc-pVTZ and B3LYP/ cc-pV5Z levels of theory,r espectively.T he corresponding harmonic and anharmonic vibrational frequencies were also evaluated at these two levels of theory.A nharmonicity,f or frequencies, was accounted for through asecond-order perturbative analysis based on numerical third and fourth derivatives, as implemented in the Gaussian 09 series of programs.…”

Section: Computational Detailsmentioning

confidence: 92%

Gas‐Phase Infrared Spectroscopy of Substituted Cyanobutadiynes: Roles of the Bromine Atom and Methyl Group as Substituents

et al. 2016

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The IR spectra of 5-bromo-2,4-pentadiynenitrile (Br-C≡C-C≡C-CN) and 2,4-hexadiynenitrile (CH3 -C≡C-C≡C-CN), a compound of interstellar interest, have been recorded within the 4000-500 cm(-1) spectral region and calculated by means of high-level ab initio and density functional calculations. Although the calculated structures of both compounds are rather similar, there are very subtle differences, mainly in the strength of the C≡C bond not directly bound to the substituent. These subtle bonding differences are reflected in small, but not negligible, differences in the electron density at the corresponding bond critical points, and, more importantly, are reflected in the IR spectra. Indeed, the IR spectrum for the bromine derivative presents two well-differentiated strong bands around 2250 cm(-1) , whereas for the methyl derivative both absorptions coalesce in a single band. These bands correspond in both cases to the coupling between C≡C and C≡N stretching displacements. A third, very weak, band also associated with C≡C and C≡N coupled stretches is observed for the bromine derivative, but not for the methyl one, owing to its extremely low intensity.

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Section: Computational Detailsmentioning

confidence: 92%

Gas‐Phase Infrared Spectroscopy of Substituted Cyanobutadiynes: Roles of the Bromine Atom and Methyl Group as Substituents

et al. 2016

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“…Our recent study has demonstrated that the cryogenic codeposition of HC 5 N/C 2 H 2 (Couturier-Tamburelli et al 2009 in Argon matrices induced the formation of a longer carbon-nitrogen chain, cyanotriacetylene (HC 7 N). We identified this species based on IR vibrational spectroscopy and on electronic luminescence spectroscopy.…”

Section: Photochemistry Of C 2 H 2 /Hc 5 N Mixturementioning

confidence: 99%

Simulation of Titan’s atmospheric photochemistry

Couturier-Tamburelli

Piétri

Gudipati

2015

A&A

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We studied the photochemistry of frozen ice of a polar Titan's atmospheric molecule cyanodiacetylene (HC 5 N) to determine the possible contribution of this compound to the lower altitude photochemistry of haze layers found on Titan. We used infrared analysis to examine the residue produced by irradiation of solid HC 5 N at λ > 300 nm. The resulting polymer is orange-brown in color. Based on theoretical analysis and the general tendency of HC 5 N and C 4 N 2 to undergo similar ice photochemistry at longer wavelengths accessible in Titan's lower atmosphere, we conclude that Titan's lower atmosphere is photochemically active in the regions of cloud, ice, and aerosol formation. C 4 N 2 is a symmetric molecule with no net dipole moment whereas, HC 5 N has a large dipole moment of ∼4 D. Consequently, though both these molecules have very similar molecular weight and size, their sublimation temperatures are different, HC 5 N subliming around 170 K compared to 160 K for C 4 N 2 . Based on our studies we conclude that in Titan's atmosphere the cyanoacetylene class of molecules (HCN, HC 3 N, HC 5 N, etc.) would condense first followed by the dicyanoacetylenes (C 2 N 2 , C 4 N 2 , C 6 N 2 , etc.), leading to fractionation of different class of molecules. From the fluxes used in the laboratory and depletion of the original HC 5 N signals, we estimate Titan's haze ice photochemistry involving polar nitriles to be significant and very similar to their non-polar counterparts.

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Cyanoacetylenic complexes as pre-reactional species leading to the HC7N synthesis. Part I: Experimental and theoretical identification of the HC3N:C4H2 complexes

Piétri¹,

Coupeaud²,

Aycard³

et al. 2009

Chemical Physics

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Cyanoacetylenic complexes as pre-reactional species leading to the HC7N synthesis. Part II: Experimental and theoretical identifications of the HC5N:C2H2 complex

Cited by 7 publications

References 21 publications

Gas‐Phase Infrared Spectroscopy of Substituted Cyanobutadiynes: Roles of the Bromine Atom and Methyl Group as Substituents

Gas‐Phase Infrared Spectroscopy of Substituted Cyanobutadiynes: Roles of the Bromine Atom and Methyl Group as Substituents

Simulation of Titan’s atmospheric photochemistry

Cyanoacetylenic complexes as pre-reactional species leading to the HC7N synthesis. Part I: Experimental and theoretical identification of the HC3N:C4H2 complexes

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