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Ghabi A, Slama T, Hedhli A, Boubaker T, Guillemin JC. Primary α-Phosphino- and α-Arseno-Nitriles, Analogues of α-Aminonitriles. Inorg Chem 2024. [PMID: 38818931 DOI: 10.1021/acs.inorgchem.4c01307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
More than 170 years after the synthesis of α-aminonitriles by the reaction of Strecker, α-phosphinonitriles, and α-arsenonitriles have been prepared and characterized by NMR and IR spectroscopy. For the simplest derivatives, the reaction was carried out by reaction of cyanomethyltributylstannane with phosphorus or arsenic trichloride, followed by a chemoselective reduction of the dichlorophosphine and dichloroarsine formed to the corresponding primary phosphine and arsine. The phosphinoacetonitrile can be stored at -80 °C for months in its pure state, but arsenoacetonitrile decomposes at this temperature. Chiral compounds can be synthesized from C-substituted cyano-1-alkyltributylstannanes. In 1H NMR spectroscopy, these chiral phosphines and arsines display diastereotopic protons for the PH2 and AsH2 groups, a property never observed for the NH2 group of α-aminonitriles. This work paves the way for further studies on the chemistry of these compounds, including a comparative chemistry of these phosphorus and arsenic derivatives with the well-known α-aminonitriles.
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Ibrahim M, Guillemin JC, Chaquin P, Markovits A, Krim L. The significant role of water in reactions occurring on the surface of interstellar ice grains: Hydrogenation of pure ketene H 2CCO ice versus hydrogenation of mixed H 2CCO/H 2O ice at 10 K. Phys Chem Chem Phys 2024; 26:4200-4207. [PMID: 38230527 DOI: 10.1039/d3cp04601j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Water ice plays an important role in reactions taking place on the surface of interstellar ice grains, ranging from catalytic effects that reduce reaction barrier heights to effects that stabilize the reaction products and intermediates formed, or that favor one reaction pathway over another, passing through water-involvement in the reaction to produce more complex molecules that cannot be formed without water or water-derived fragments H, O and OH. In this context, we have combined experimental and theoretical studies to investigate ketene (CH2CO) + H solid-state reaction at 10 K in the presence and absence of water molecules under interstellar conditions, through H-bombardment of CH2CO and CH2CO/H2O ices. We show in the present study that with or without water, the ketene molecule reacts with H atoms to form four reaction products, namely CO, H2CO, CH4 and CH3CHO. Based on the amounts of CH2CO consumed during the hydrogenation processes, the CH2CO + 2H reaction appears to be more efficient in the presence of water. This underlines the catalytic role of water ice in reactions occurring on the surface of interstellar ice grains. However, if we refer to the yields of reaction products formed during the hydrogenation of CH2CO and CH2CO/H2O ices, we find that water molecules favor the reaction pathway to form CH3CHO and deactivate that leading to CH4 and H2CO. These experimental results are in good agreements with the theoretical predictions that highlight the catalytic effect of H2O on the CH2CO + H reaction, whose potential energy barrier drops from 4.6 kcal mol-1 (without water) to 3.8 and 3.6 kcal mol-1 with one and two water molecules respectively.
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Mó O, Lamsabhi AM, Guillemin JC, Yáñez M. Ionization, intrinsic basicity, and intrinsic acidity of unsaturated diols of astrochemical interest: 1,1- and 1,2-ethenediol: A theoretical survey. J Comput Chem 2023. [PMID: 37698484 DOI: 10.1002/jcc.27223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/23/2023] [Accepted: 08/25/2023] [Indexed: 09/13/2023]
Abstract
The structure, stability, and bonding characteristics of 1,1- and 1,2-ethenediol, their radical cations, and their protonated and deprotonated species were investigated using high-level ab initio G4 calculations. The electron density of all the neutral and charged systems investigated was analyzed using the QTAIM, ELF, and NBO approaches. The vertical ionization potential (IP) of the five stable tautomers of 1,2-ethenediol and the two stable tautomers of 1,1-ethenediol go from 11.81 to 12.27 eV, whereas the adiabatic ones go from 11.00 to 11.72 eV. The adiabatic ionization leads to a significant charge delocalization along the O-C-C-O skeleton. The most stable protonated form of (Z)-1,2-ethenediol can be reached by the protonation of both the anti-anti and the syn-anti conformers, whereas the most stable deprotonated form arises only from the syn-anti one. Both charged species are extra-stabilized by the formation of an O-H···O intramolecular hydrogen bond (IHB) which is not found in the neutral system. (Z)-1,2-ethenediol is predicted to be less stable, less basic, and more acidic than its cis-glycolaldehyde isomer. The most stable protonated species of (E)-1,2-ethenediol comes from its syn-syn conformer, although the anti-anti conformer is the most basic one. Contrarily, the three conformers yield a common deprotonated species, so their acidity follows exactly their relative stability. Again, the (E)-1,2-ethenediol is predicted to be less stable, less basic, and more acidic than its trans-glycolaldehyde isomer. Neither the neutral nor the protonated or the deprotonated forms of 1,1-ethenediol show the formation of any O-H···O IHB. The most stable protonated species is formed by the protonation of any of the two tautomers, but the most stable deprotonated form arises exclusively from the syn-anti neutral conformer. The conformers of 1,1-ethenediol are much less stable and significantly less basic than their isomer, acetic acid, and only slightly more acidic.
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Lawzer AL, Ganesan E, Gronowski M, Custer T, Guillemin JC, Kołos R. Free Ethynylarsinidene and Ethynylstibinidene: Heavier Analogues of Nitrenes and Phosphinidenes. Chemistry 2023; 29:e202300887. [PMID: 37278982 DOI: 10.1002/chem.202300887] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/25/2023] [Accepted: 06/06/2023] [Indexed: 06/07/2023]
Abstract
Until now, there has been very little experimental evidence for the existence of free arsinidenes and stibinidenes, apart from the hydrides, AsH and SbH. Here, we report on photogeneration of triplet ethynylarsinidene, HCCAs, and triplet ethynylstibinidene, HCCSb, from ethynylarsine and ethynylstibine, respectively, in solid argon matrices. The products were identified using infrared spectroscopy and the associated UV absorption spectra are interpreted with the aid of theoretical predictions.
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Ayachi H, Gazzeh H, Boubaker T, Guillemin JC. Methylenecyanamide (CH 2═NCN) and ( Z)- and ( E)-Iminoacetonitriles (NC-CH═NH), Dimers of Hydrogen Cyanide. J Org Chem 2023; 88:2570-2574. [PMID: 36709430 DOI: 10.1021/acs.joc.2c02493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
(Z)- and (E)-iminoacetonitriles (NCCH═NH), two hydrogen cyanide dimers, are described as key compounds in prebiotic chemistry. Among the many possible dimers of HCN with covalent bonds, even the second on the scale of thermodynamic stability, methylenecyanamide (CH2═NCN), has been investigated little. We show that this compound can be isolated, is stable enough to give an adduct with a nucleophile or a diene, and can be easily generated under prebiotic conditions, highlighting a possible role in this medium. Comparison between isomers shows significant differences in formation and chemical reactivity.
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Ibrahim M, Guillemin JC, Chaquin P, Markovits A, Krim L. Formation of CO, CH 4, H 2CO and CH 3CHO through the H 2CCO + H surface reaction under interstellar conditions. Phys Chem Chem Phys 2022; 24:23245-23253. [PMID: 36134501 DOI: 10.1039/d2cp02980d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of ketene (H2CCO) with hydrogen atoms has been studied under interstellar conditions through two different experimental methods, occurring on the surface and in the bulk of H2CCO ice. We show that ketene interaction with H-atoms at 10 K leads mainly to four reaction products, carbon monoxide (CO), methane (CH4), formaldehyde (H2CO) and acetaldehyde (CH3CHO). A part of these results shows a chemical link between a simple organic molecule such as H2CCO and a complex one such as CH3CHO, through H-addition reactions taking place in dense molecular clouds. The H-addition processes are very often proposed by astrophysical models as mechanisms for the formation of complex organic molecules based on the abundance of species already detected in the interstellar medium. However, the present study shows that the hydrogenation of ketene under non-energetic conditions may also lead efficiently to fragmentation processes and the formation of small species such as CO, CH4 and H2CO, without supplying external energy such as UV photons or high energy particles. Such fragmentation pathways should be included in the astrophysical modeling of H2CCO + H in the molecular clouds of the interstellar medium. To support these results, theoretical calculations have explicitly showed that, under our experimental conditions, H-atom interactions with the CC bond of ketene lead mainly to CH3CHO, CH4 and CO. By investigating the formation and reactivity of the reaction intermediate H3C-CO radical, our calculations demonstrate that the H3C-CO + H reaction evolves through two barrierless pathways to form either CH3CHO or CH4 and CO fragments.
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Ganesan E, Custer T, Lawzer AL, Guillemin JC, Kołos R. Unusual Quartet‐Doublet Phosphorescence from the Phosphaethynyl Radical, CP. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202210521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Melli A, Melosso M, Bizzocchi L, Alessandrini S, Jiang N, Tonolo F, Boi S, Castellan G, Sapienza C, Guillemin JC, Dore L, Puzzarini C. Rotational Spectra of Unsaturated Carbon Chains Produced by Pyrolysis: The Case of Propadienone, Cyanovinylacetylene, and Allenylacetylene. J Phys Chem A 2022; 126:6210-6220. [PMID: 36044202 PMCID: PMC9483987 DOI: 10.1021/acs.jpca.2c05018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Several interstellar molecules are highly reactive unsaturated
carbon chains, which are unstable under terrestrial conditions. Laboratory
studies in support of their detection in space thus face the issue
of how to produce these species and how to correctly model their rotational
energy levels. In this work, we introduce a general approach for producing
and investigating unsaturated carbon chains by means of selected test
cases. We report a comprehensive theoretical/experimental spectroscopic
characterization of three species, namely, propadienone, cyanovinylacetylene,
and allenylacetylene, all of them being produced by means of flash
vacuum pyrolysis of a suitable precursor. For each species, quantum-chemical
calculations have been carried out with the aim of obtaining accurate
predictions of the missing spectroscopic information required to guide
spectral analysis and assignment. Rotational spectra of the title
molecules have been investigated up to 400 GHz by using a frequency-modulation
millimeter-/submillimeter-wave spectrometer, thus significantly extending
spectral predictions over a wide range of frequency and quantum numbers.
A comparison between our results and those available in the literature
points out the clear need of the reported laboratory measurements
at higher frequencies for setting up accurate line catalogs for astronomical
searches.
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Jiang N, Melosso M, Bizzocchi L, Alessandrini S, Guillemin JC, Dore L, Puzzarini C. Spectroscopic and Computational Characterization of 2-Aza-1,3-butadiene, a Molecule of Astrochemical Significance. J Phys Chem A 2022; 126:1881-1888. [PMID: 35275628 PMCID: PMC8958585 DOI: 10.1021/acs.jpca.2c00831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Being N-substituted
unsaturated species, azabutadienes are molecules
of potential relevance in astrochemistry, ranging from the interstellar
medium to Titan’s atmosphere. 2-Azabutadiene and butadiene
share a similar conjugated π system, thus allowing investigation
of the effects of heteroatom substitution. More interestingly, 2-azabutadiene
can be used to proxy the abundance of interstellar butadiene. To enable
future astronomical searches, the rotational spectrum of 2-azabutadiene
has been investigated up to 330 GHz. The experimental work has been
supported and guided by accurate computational characterization of
the molecular structure, energetics, and spectroscopic properties
of the two possible forms, trans and gauche. The trans species, more stable by about 7 kJ/mol
than gauche-2-azabutadiene, has been experimentally
observed, and its rotational and centrifugal distortion constants
have been obtained with remarkable accuracy, while theoretical estimates
of the spectroscopic parameters are reported for gauche-2-azabutadiene.
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Melosso M, Bizzocchi L, Gazzeh H, Tonolo F, Guillemin JC, Alessandrini S, Rivilla VM, Dore L, Barone V, Puzzarini C. Gas-phase identification of ( Z)-1,2-ethenediol, a key prebiotic intermediate in the formose reaction. Chem Commun (Camb) 2022; 58:2750-2753. [PMID: 35119446 DOI: 10.1039/d1cc06919e] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Prebiotic sugars are thought to be formed on primitive Earth by the formose reaction. However, their formation is not fully understood and it is plausible that key intermediates could have formed in extraterrestrial environments and subsequently delivered on early Earth by cometary bodies. 1,2-Ethenediol, the enol form of glycolaldehyde, represents a highly reactive intermediate of the formose reaction and is likely detectable in the interstellar medium. Here, we report the identification and first characterization of (Z)-1,2-ethenediol by means of rotational spectroscopy. The title compound has been produced in the gas phase by flash vacuum pyrolysis of bis-exo-5-norbornene-2,3-diol at 750 °C, through a retro-Diels-Alder reaction. The spectral analysis was guided by high-level quantum-chemical calculations, which predicted spectroscopic parameters in very good agreement with the experiment. Our study provides accurate spectral data to be used for searches of (Z)-1,2-ethenediol in the interstellar space.
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Cabezas C, Chang CH, Guillemin JC, Endo Y. Gas-phase spectroscopic identification of the chlorovinyl radical. Phys Chem Chem Phys 2022; 24:25099-25105. [DOI: 10.1039/d2cp03578b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fourier transform microwave spectra for two isomers of the chlorine substituted vinyl radical have been observed in the 4-52 GHz frequency region. The observed radicals (2A´) have been generated using...
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Lawzer AL, Custer T, Guillemin JC, Kołos R. An Efficient Photochemical Route Towards Triplet Ethynylphosphinidene, HCCP. Angew Chem Int Ed Engl 2021; 60:6400-6402. [PMID: 33320979 DOI: 10.1002/anie.202016052] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Indexed: 11/09/2022]
Abstract
While the archetypal free phosphinidene, H-P, has been studied for over a century, reports on uncomplexed, univalent phosphorus compounds are very sparse. Here we demonstrate production of HCCP in solid argon through the UV-induced rearrangement and subsequent dehydrogenation of phosphapropyne, CH3 CP. Migration of H atoms along the CCP backbone of CH3 CP resulted in production of the previously unobserved species 1-phosphapropadiene, CH2 =C=PH, followed by ethynylphosphine, HCCPH2 .
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Szczepaniak U, Gutiérrez-Quintanilla A, Crépin C, Guillemin JC, Turowski M, Custer T, Kołos R. Spectroscopy of methylcyanodiacetylene revisited. Solid parahydrogen and solid neon matrix studies. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Derbali I, Hrodmarsson HR, Schwell M, Bénilan Y, Poisson L, Hochlaf M, Alikhani ME, Guillemin JC, Zins EL. Unimolecular decomposition of methyl ketene and its dimer in the gas phase: theory and experiment. Phys Chem Chem Phys 2020; 22:20394-20408. [PMID: 32914152 DOI: 10.1039/d0cp03921g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a combined theoretical and experimental investigation on the single photoionization and dissociative photoionization of gas-phase methyl ketene (MKE) and its neutral dimer (MKE2). The performed experiments entail the recording of photoelectron photoion coincidence (PEPICO) spectra and slow photoelectron spectra (SPES) in the energy regime 8.7-15.5 eV using linearly polarized synchrotron radiation. We observe both dimerization and trimerization of the monomer which brings about significantly complex and abstruse dissociative ionization patterns. These require the implementation of theoretical calculations to explore the potential energy surfaces of the monomer and dimer's neutral and ionized geometries. To this end, explicitly correlated quantum chemical methodologies involving the coupled cluster with single, double and perturbative triple excitations (R)CCSD(T)-F12 method, are utilized. An improvement in the adiabatic ionization energy of MKE is presented (AIE = 8.937 ± 0.020 eV) as well as appearance energies for multiple fragments formed through dissociative ionization of either the MKE monomer or dimer. In this regard, the synergy of experiment and theory is crucial to interpreting the obtained results. We discuss the potential astrochemical implications of this work in the context of recent advances in the field of astrochemistry and speculate on the potential presence and eventual fate of interstellar MKE molecules.
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Harper OJ, Coudert LH, Loison JC, Gans B, Douin S, Garcia GA, Guillemin JC, Boyé-Péronne S. Quasi-symmetry effects in the threshold photoelectron spectrum of methyl isocyanate. J Chem Phys 2020; 153:074308. [DOI: 10.1063/5.0017753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Szczepaniak U, Ozaki K, Tanaka K, Ohnishi Y, Wada Y, Guillemin JC, Crépin C, Kołos R, Morisawa Y, Suzuki H, Wakabayashi T. Phosphorescence excitation mapping and vibrational spectroscopy of HC9N and HC11N cyanopolyynes in organic solvents. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gans B, Hartweg S, Garcia GA, Boyé-Péronne S, Harper OJ, Guillemin JC, Loison JC. VUV photoionization of the CH2NC radical: adiabatic ionization energy and cationic vibrational mode wavenumber determinations. Phys Chem Chem Phys 2020; 22:12496-12501. [DOI: 10.1039/d0cp01901a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photoelectron spectroscopy of CH2NC (isocyanomethyl) radical species is investigated for the first time between 9.3 and 11.2 eV in the vicinity of the first photoionizing transition X+1A1 ← X 2B1.
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Ja'o AM, Masters SL, Wann DA, Rankine CD, Nunes JPF, Guillemin JC. Direct Experimental Observation of in situ Dehydrogenation of an Amine-Borane System Using Gas Electron Diffraction. J Phys Chem A 2019; 123:7104-7112. [PMID: 31314528 DOI: 10.1021/acs.jpca.9b05522] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In situ dehydrogenation of azetidine-BH3, which is a candidate for hydrogen storage, was observed with the parent and dehydrogenated analogue subjected to rigorous structural and thermochemical investigations. The structural analyses utilized gas electron diffraction supported by high-level quantum calculations, while the pathway for the unimolecular hydrogen release reaction in the absence and presence of BH3 as a bifunctional catalyst was predicted at the CBS-QB3 level. The catalyzed dehydrogenation pathway has a barrier lower than the predicted B-N bond dissociation energy, hence favoring the dehydrogenation process over the dissociation of the complex. The predicted enthalpy of dehydrogenation at the CCSD(T)/CBS level indicates that mild reaction conditions would be required for hydrogen release and that the compound is closer to thermoneutral than linear amine boranes. The entropy and free energy change for the dehydrogenation process show that the reaction is exergonic, energetically feasible, and will proceed spontaneously toward hydrogen release, all of which are important factors for hydrogen storage.
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Cabezas C, Barrientos C, Largo A, Guillemin JC, Cernicharo J, Alonso JL. Alkaline and Alkaline-earth Cyanoacetylides: A Combined Theoretical and Rotational Spectroscopic Investigation. J Chem Phys 2019; 151:054312. [PMID: 31511749 PMCID: PMC6739221 DOI: 10.1063/1.5110670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The metallic cyanoacetylides LiC3N, NaC3N, MgC3N and CaC3N have been investigated by combined spectroscopy measurements and theoretical calculations. The theoretical calculations predict for the four species that the linear isomer with formula MCCCN (M= Li, Na, Mg and Ca) is the most stable one. We used the laser ablation molecular beam Fourier transform microwave spectroscopy to synthesize these species by the reaction of metal vapors, produced by laser ablation, and the 3-bromo-2-propynenitrile (BrCCCN). The pure rotational spectra were observed by Fourier transform microwave spectroscopy in the 2-18 GHz frequency region only for LiCCCN and NaCCCN, while no spectral signatures for MgCCCN and CaCCCN could be detected. Finally, we have searched for LiCCCN and NaCCCN species towards the carbon-rich evolved star IRC + 10216 but only upper limits to their abundances have been obtained.
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Escalona JT, Guillemin JC, Darrigan C, Chrostowska A. Spectroscopic Studies on Hydrazine-Boranes, Key Compounds for Chemical Hydrogen Storage. J Phys Chem A 2019; 123:6003-6015. [PMID: 31283226 DOI: 10.1021/acs.jpca.9b04266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrazine-boranes (H2NNH2·BH3 and H3B·NH2NH2·BH3) have been proposed for the storage of hydrogen, but these compounds have not created scope for extensive research works as ammonia- and methylamine-boranes have made these last decades. In the exciting research devoted to energy storage with environmentally friendly processes, hydrazine-borane, hydrazine-bisborane, and their simply substituted derivatives could provide a satisfactory response for hydrogen production and recyclability of the formed products. To date, knowledge of the physical and chemical properties of these compounds is still scarce. In this paper, the electronic structure of various hydrazine-boranes complexes is studied by ultraviolet-photoelectron spectroscopy (UV-PES), which is the experimental technique giving direct access to the energy of occupied molecular orbitals. Thus, UV-PE spectra were registered and first ionization energies were determined. Understanding of different types of interactions between nitrogen lone pairs and their variations by complexation has been our essential goal in these studies. In particular, clear stabilization of all molecular orbital energies is noted when complexation with borane takes place. Evolution of the σBN bond during the hydrogen release process upon thermal activation has also been studied experimentally by UV-PES and supported by quantum chemical calculations.
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Derbali I, Hrodmarsson HR, Gouid Z, Schwell M, Gazeau MC, Guillemin JC, Hochlaf M, Alikhani ME, Zins EL. Photoionization and dissociative photoionization of propynal in the gas phase: theory and experiment. Phys Chem Chem Phys 2019; 21:14053-14062. [PMID: 30652173 DOI: 10.1039/c8cp06751a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Propynal (HCCCHO) is a complex organic compound (COM) of astrochemical and astrobiological interest. We present a combined theoretical and experimental investigation on the single photon ionization of gas-phase propynal, in the 10 to 15.75 eV energy range. Fragmentation pathways of the resulting cation were investigated both theoretically and experimentally. The adiabatic ionization energy (AIE) has been measured to be AIEexp = 10.715 ± 0.005 eV using tunable VUV synchrotron radiation coupled with a double imaging photoelectron photoion coincidence (i2PEPICO) spectrometer. In the energy range under study, three fragments formed by dissociative photoionization were identified experimentally: HC3O+, HCO+ and C2H2+, and their respective appearance energies (AE) were found to be AE = 11.26 ± 0.03, 13.4 ± 0.3 and 11.15 ± 0.03 eV, respectively. Using explicitly correlated coupled cluster calculations and after inclusion of the zero point vibrational energy, core-valence and scalar relativistic effects, the AIE is calculated to be AIEcalc = 10.717 eV, in excellent agreement with the experimental finding. The appearance energies of the fragments were calculated using a similar methodological approach. To further interpret the observed vibrational structure, anharmonic frequencies were calculated for the fundamental electronic state of the propynal cation. Moreover, MRCI calculations were carried out to understand the population of excited states of the cationic species. This combined experimental and theoretical study will help to understand the presence and chemical evolution of propynal in the external parts of interstellar clouds where it has been observed.
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Gans B, Lamarre N, Guillemin JC, Douin S, Alcaraz C, Romanzin C, Garcia GA, Liévin J, Boyé-Péronne S. Vibronic structure of the cyanobutadiyne cation. I. VUV photoionization study of HC 5N. J Chem Phys 2019; 150:244304. [DOI: 10.1063/1.5097688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Custer T, Szczepaniak U, Gronowski M, Piétri N, Couturier-Tamburelli I, Guillemin JC, Turowski M, Kołos R. Isomerization of cyanopropyne in solid argon. Phys Chem Chem Phys 2019; 21:13668-13678. [PMID: 31190036 DOI: 10.1039/c8cp06739b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyanopropyne, CH3-C[triple bond, length as m-dash]C-CN, is a simple molecule whose photochemistry is still unexplored. Here we investigate the UV photolysis of this astrophysically significant nitrile trapped in solid argon. The FTIR study was assisted with 15N-isotopic substitution data and with DFT-level computations including the analyses of ground- and excited-state potential energy surfaces. Cyanopropyne was found to decay mainly via a two-step isomerization process. Infrared absorption spectra evolved to show signals from allenyl cyanide, CH2[double bond, length as m-dash]C[double bond, length as m-dash]CH-CN, which then further convert into propargyl cyanide, H-C[triple bond, length as m-dash]C-CH2-CN. Some evidence for the presence of allenyl isocyanide, propargyl isocyanide, 3-cyanocyclopropene, and 1,2,3-butatrien-1-imine under particular experimental conditions was also observed. Although cyano/isocyano interconversion has been observed during photolysis of other closely related species in solid argon matrices, including H-C[triple bond, length as m-dash]C-CN, no evidence could be found for production of 1-isocyano-1-propyne, CH3-C[triple bond, length as m-dash]C-NC for these experiments.
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Zapała J, Custer T, Guillemin JC, Gronowski M. Photochemistry of XCH 2CN (X = -Cl, -SH) in Argon Matrices. J Phys Chem A 2019; 123:3818-3830. [PMID: 30974940 DOI: 10.1021/acs.jpca.9b01983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report infrared spectra and photochemical behavior of the potentially astrochemically significant species, mercaptoacetonitrile (HS-CH2C≡N) and, for comparison purposes, chloroacetonitrile (Cl-CH2C≡N), both suspended in an argon matrix at 6 K. Photolytic formation of the isocyano products HS-CH2-NC and Cl-CH2-NC were observed as well as CH3NSC and CH3SCN (in HS-CH2CN photolysis). While no dissociation products were observed for Cl-CH2-CN, photolysis of HS-CH2-CN produced compounds necessitating the loss of the CN group to form CH2═S, the SH group to form H2C-CN and HC-CN, or both CN and SH to form CH3 and CH4. Observation of emission spectra upon annealing indicates the presence of free sulfur atom in matrices of photolyzed HS-CH2-CN.
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Cabezas C, Guillemin JC, Endo Y. Fourier transform microwave spectroscopy of Criegee intermediates: The conformational behaviour of butyraldehyde oxide. J Chem Phys 2019; 150:104301. [DOI: 10.1063/1.5088566] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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