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Caracciolo A, Vanuzzo G, Balucani N, Stranges D, Tanteri S, Cavallotti C, Casavecchia P. Crossed molecular beams and theoretical studies of the O(3P)+ 1,2-butadiene reaction: Dominant formation of propene+CO and ethylidene+ketene molecular channels. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1812281] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Caracciolo A, Lu D, Balucani N, Vanuzzo G, Stranges D, Wang X, Li J, Guo H, Casavecchia P. Combined Experimental-Theoretical Study of the OH + CO → H + CO 2 Reaction Dynamics. J Phys Chem Lett 2018; 9:1229-1236. [PMID: 29470075 DOI: 10.1021/acs.jpclett.7b03439] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A combined experimental-theoretical study is performed to advance our understanding of the dynamics of the prototypical tetra-atom, complex-forming reaction OH + CO → H + CO2, which is also of great practical relevance in combustion, Earth's atmosphere, and, potentially, Mars's atmosphere and interstellar chemistry. New crossed molecular beam experiments with mass spectrometric detection are analyzed together with the results from previous experiments and compared with quasi-classical trajectory (QCT) calculations on a new, full-dimensional potential energy surface (PES). Comparisons between experiment and theory are carried out both in the center-of-mass and laboratory frames. Good agreement is found between experiment and theory, both for product angular and translational energy distributions, leading to the conclusion that the new PES is the most accurate at present in elucidating the dynamics of this fundamental reaction. Yet, small deviations between experiment and theory remain and are presumably attributable to the QCT treatment of the scattering dynamics.
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Rosi M, Mancini L, Skouteris D, Ceccarelli C, Faginas Lago N, Podio L, Codella C, Lefloch B, Balucani N. Possible scenarios for SiS formation in the interstellar medium: Electronic structure calculations of the potential energy surfaces for the reactions of the SiH radical with atomic sulphur and S2. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.01.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Sleiman C, El Dib G, Rosi M, Skouteris D, Balucani N, Canosa A. Low temperature kinetics and theoretical studies of the reaction CN + CH 3NH 2: a potential source of cyanamide and methyl cyanamide in the interstellar medium. Phys Chem Chem Phys 2018; 20:5478-5489. [PMID: 29082409 DOI: 10.1039/c7cp05746f] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction between cyano radicals (which are ubiquitous in interstellar clouds) and methylamine (a molecule detected in various interstellar sources) has been investigated in a synergistic experimental and theoretical study. The reaction has been found to be very fast in the entire range of temperatures investigated (23-297 K) by using a CRESU apparatus coupled to pulsed laser photolysis - laser induced fluorescence. The global experimental rate coefficient is given by In addition, dedicated electronic structure calculations of the underlying potential energy surface have been performed, together with capture theory and RRKM calculations. The experimental data have been interpreted in the light of the theoretical calculations and the product branching ratio has been established. According to the present study, in the range of temperatures investigated the title reaction is an efficient interstellar route of formation of cyanamide, NH2CN, another interstellar species. The second most important channel is the one leading to methyl cyanamide, CH3NHCN (an isomer of aminoacetonitrile), via a CN/H exchange mechanism with a yield of 12% of the global reaction in the entire range of temperatures explored. For a possible inclusion in future astrochemical models we suggest, by referring to the usual expression the following values: α = 3.68 × 10-12 cm3 molec-1 s-1, β = -1.80, γ = 7.79 K for the channel leading to NH2CN + CH3; α = 5.05 × 10-13 cm3 molec-1 s-1, β = -1.82, γ = 7.93 K for the channel leading to CH3NHCN + H.
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Kaiser RI, Balucani N. Exploring the Gas Phase Synthesis of the Elusive Class of Boronyls and the Mechanism of Boronyl Radical Reactions under Single Collision Conditions. Acc Chem Res 2017; 50:1154-1162. [PMID: 27991767 DOI: 10.1021/ar300308u] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Until recently, the chemistry of boronyl (BO), a diatomic radical isolectronic with the cyano (CN) species, has remained unknown. The boronyl group is characterized by a boron-oxygen multiple bond, and because of the inherent electron deficiency of the boron atom, boronyls (RBO) are highly reactive and typically only exist in their cyclotrimeric form (RBO)3. Due to their invaluable role as reactants, the isolation of the monomers in gas phase experiments has been extensively sought after by the organic synthesis and physical organic chemistry communities but never achieved. Besides the interests from a physical organic and synthetic point of view, boronyls also play a role as reaction intermediates in boron-assisted rocket propulsion systems. In this Account, we review recent experimental work in which gas phase organo boronyl monomers (RBO) are formed via bimolecular reactions of the boronyl radical (BO) with C2-C6 unsaturated hydrocarbons. The investigated hydrocarbons are widely exploited as fuels, and their reactions with boronyl radicals under single collision conditions lead to the formation of organo boronyls. Our studies also elucidate the mechanisms of their formation reactions thus furnishing a comprehension at the molecular level of this reaction class. The variety of the employed hydrocarbon substrates has allowed us to systematically classify the chemical behavior of the boronyl radicals. With the exception of the case of the dimethylacetylene reaction, the boron monoxide radical versus atomic hydrogen exchange mechanisms were always open leading to the formation of highly unsaturated organo boronyl monomers (RBO), which could be easily identified because they cannot trimerize under single collision conditions. Besides the hydrogen displacement pathway, methylacetylene, dimethylacetylene, and propylene, carrying one or two methyl groups, were also found to eliminate a methyl group. In all systems, the reactions were barrierless, indirect, and initiated by addition of the boron monoxide radical to the π electron density of the hydrocarbon molecule, with the radical center located at the boron atom of the BO radical, thus leading to doublet radical intermediates. These intermediates either decompose via hydrogen or methyl loss or isomerize prior to their decomposition via atomic hydrogen or migration of the BO moiety. A consistent trend suggests that all exit transition states are rather tight with those involved in the hydrogen atom loss depicting exit barriers of typically 25 to 35 kJ mol-1, whereas the methyl loss pathways are associated with tighter exit transition states located about 30-50 kJ mol-1 above the separated products. Further, the overall energetics suggest that those bimolecular reactions are exoergic by 40-90 kJ mol-1. These findings confirm that this reaction class leads to the formation of highly unsaturated organo boronyl molecules.
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Skouteris D, Vazart F, Ceccarelli C, Balucani N, Puzzarini C, Barone V. New quantum chemical computations of formamide deuteration support a gas-phase formation of this prebiotic molecule. ACTA ACUST UNITED AC 2017. [DOI: 10.1093/mnrasl/slx012] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Balucani N, Bowman JM, Connor JNL, Lee YT. Tribute to Piergiorgio Casavecchia and Antonio Laganà. J Phys Chem A 2016; 120:4565-7. [DOI: 10.1021/acs.jpca.6b05527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gimondi I, Cavallotti C, Vanuzzo G, Balucani N, Casavecchia P. Reaction Dynamics of O(3P) + Propyne: II. Primary Products, Branching Ratios, and Role of Intersystem Crossing from Ab Initio Coupled Triplet/Singlet Potential Energy Surfaces and Statistical Calculations. J Phys Chem A 2016; 120:4619-33. [DOI: 10.1021/acs.jpca.6b01564] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Vanuzzo G, Balucani N, Leonori F, Stranges D, Nevrly V, Falcinelli S, Bergeat A, Casavecchia P, Cavallotti C. Reaction Dynamics of O(3P) + Propyne: I. Primary Products, Branching Ratios, and Role of Intersystem Crossing from Crossed Molecular Beam Experiments. J Phys Chem A 2016; 120:4603-18. [DOI: 10.1021/acs.jpca.6b01563] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Vanuzzo G, Balucani N, Leonori F, Stranges D, Falcinelli S, Bergeat A, Casavecchia P, Gimondi I, Cavallotti C. Isomer-Specific Chemistry in the Propyne and Allene Reactions with Oxygen Atoms: CH3CH + CO versus CH2CH2 + CO Products. J Phys Chem Lett 2016; 7:1010-1015. [PMID: 26930465 DOI: 10.1021/acs.jpclett.6b00262] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report direct experimental and theoretical evidence that, under single-collision conditions, the dominant product channels of the O((3)P) + propyne and O((3)P) + allene isomeric reactions lead in both cases to CO formation, but the coproducts are singlet ethylidene ((1)CH3CH) and singlet ethylene (CH2CH2), respectively. These data, which settle a long-standing issue on whether ethylidene is actually formed in the O((3)P) + propyne reaction, suggest that formation of CO + alkylidene biradicals may be a common mechanism in O((3)P) + alkyne reactions, in contrast to formation of CO + alkene molecular products in the corresponding isomeric O((3)P) + diene reactions, either in combustion or other gaseous environments. These findings are of fundamental relevance and may have implications for improved combustion models. Moreover, we predict that the so far neglected (1)CH3CH + CO channel is among the main reaction routes also when the C3H4O singlet potential energy surface is accessed from the OH + C3H3 (propargyl) entrance channel, which are radical species playing a key role in many combustion systems.
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Enrique-Romero J, Rimola A, Ceccarelli C, Balucani N. The (impossible?) formation of acetaldehyde on the grain surfaces: insights from quantum chemical calculations. ACTA ACUST UNITED AC 2016. [DOI: 10.1093/mnrasl/slw031] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Balucani N, Leonori F, Casavecchia P, Fu B, Bowman JM. Crossed Molecular Beams and Quasiclassical Trajectory Surface Hopping Studies of the Multichannel Nonadiabatic O(3P) + Ethylene Reaction at High Collision Energy. J Phys Chem A 2015; 119:12498-511. [DOI: 10.1021/acs.jpca.5b07979] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Vazart F, Latouche C, Skouteris D, Balucani N, Barone V. CYANOMETHANIMINE ISOMERS IN COLD INTERSTELLAR CLOUDS: INSIGHTS FROM ELECTRONIC STRUCTURE AND KINETIC CALCULATIONS. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/810/2/111] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Barone V, Latouche C, Skouteris D, Vazart F, Balucani N, Ceccarelli C, Lefloch B. Gas-phase formation of the prebiotic molecule formamide: insights from new quantum computations. ACTA ACUST UNITED AC 2015. [DOI: 10.1093/mnrasl/slv094] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Casavecchia P, Leonori F, Balucani N. Reaction dynamics of oxygen atoms with unsaturated hydrocarbons from crossed molecular beam studies: primary products, branching ratios and role of intersystem crossing. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1039293] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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41
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Balucani N, Cartechini L, Casavecchia P, Homayoon Z, Bowman JM. A combined crossed molecular beam and quasiclassical trajectory study of the Titan-relevant N( 2D) + D 2O reaction. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1028499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Balucani N, Ceccarelli C, Taquet V. Formation of complex organic molecules in cold objects: the role of gas-phase reactions. ACTA ACUST UNITED AC 2015. [DOI: 10.1093/mnrasl/slv009] [Citation(s) in RCA: 186] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Cavallotti C, Leonori F, Balucani N, Nevrly V, Bergeat A, Falcinelli S, Vanuzzo G, Casavecchia P. Relevance of the Channel Leading to Formaldehyde + Triplet Ethylidene in the O((3)P) + Propene Reaction under Combustion Conditions. J Phys Chem Lett 2014; 5:4213-4218. [PMID: 26278956 DOI: 10.1021/jz502236y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Comprehension of the detailed mechanism of O((3)P) + unsaturated hydrocarbon reactions is complicated by the existence of many possible channels and intersystem crossing (ISC) between triplet and singlet potential energy surfaces (PESs). We report synergic experimental/theoretical studies of the O((3)P) + propene reaction by combining crossed molecular beams experiments using mass spectrometric detection at 9.3 kcal/mol collision energy (Ec) with high-level ab initio electronic structure calculations of the triplet PES and RRKM/master equation computations of branching ratios (BRs) including ISC. At high Ec's and temperatures higher than 1000 K, main products are found to be formaldehyde (H2CO) and triplet ethylidene ((3)CH3CH) formed in a reaction channel that has never been identified or considered significant in previous kinetics studies at 300 K and that, as such, is not included in combustion kinetics models. Global and channel-specific rate constants were computed and are reported as a function of temperature and pressure. This study shows that BRs of multichannel reactions useful for combustion modeling cannot be extrapolated from room-temperature kinetics studies.
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Homayoon Z, Bowman JM, Balucani N, Casavecchia P. Quasiclassical Trajectory Calculations of the N((2)D) + H2O Reaction Elucidating the Formation Mechanism of HNO and HON Seen in Molecular Beam Experiments. J Phys Chem Lett 2014; 5:3508-3513. [PMID: 26278601 DOI: 10.1021/jz501757s] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The N((2)D) + H2O is a reaction with competitive product channels, passing through several intermediates. Dynamics of this reaction had been investigated by two of the present authors at two collision energies, Ec, using the crossed molecular beams mass spectrometric method ( Faraday Discuss. 2001 , 119 , 27 - 49 ). The complicated mechanism of this reaction and puzzling results encouraged us to investigate the reaction in a joint experimental/theoretical study. Quasiclassical trajectory (QCT) calculations on an ab initio potential energy surface describing all channels of the title reaction are done with a focus on the N/H exchange channels. Interesting results of QCT calculations, in very good agreement with experimental data, reveal subtle details of the reaction dynamics of the title reaction to HNO/HON + H exit channels by disentangling the different routes to formation of the two possible HNO/HON isomers and therefore assisting in a critical manner the derivation of the reaction mechanism. Results of the present study show that the nonstatistical HNOH intermediate governs exit channels; therefore, the HON channel is as important as that of HNO. The study also confirms that the H2 + NO molecular channel is negligible even though the barrier to its formation is calculated to be well below the reactant asymptote.
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Leonori F, Balucani N, Capozza G, Segoloni E, Volpi GG, Casavecchia P. Dynamics of the O(3P) + C2H2 reaction from crossed molecular beam experiments with soft electron ionization detection. Phys Chem Chem Phys 2014; 16:10008-22. [DOI: 10.1039/c3cp54729a] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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46
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Shannon RJ, Cossou C, Loison JC, Caubet P, Balucani N, Seakins PW, Wakelam V, Hickson KM. The fast C(3P) + CH3OH reaction as an efficient loss process for gas-phase interstellar methanol. RSC Adv 2014. [DOI: 10.1039/c4ra03036b] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The reaction between ground state atomic carbon and methanol is shown to be an efficient destruction mechanism for interstellar methanol.
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Parker DSN, Dangi BB, Balucani N, Stranges D, Mebel AM, Kaiser RI. Gas-phase synthesis of phenyl oxoborane (C6H5BO) via the reaction of boron monoxide with benzene. J Org Chem 2013; 78:11896-900. [PMID: 24191702 DOI: 10.1021/jo401942z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Organyl oxoboranes (RBO) are valuable reagents in organic synthesis due to their role in Suzuki coupling reactions. However, organyl oxoboranes (RBO) are only found in trimeric forms (RBO3) commonly known as boronic acids or boroxins; obtaining their monomers has proved a complex endeavor. Here, we demonstrate an oligomerization-free formation of organyl oxoborane (RBO) monomers in the gas phase by a radical substitution reaction under single-collision conditions in the gas phase. Using the cross molecular beams technique, phenyl oxoborane (C6H5BO) is formed through the reaction of boronyl radicals (BO) with benzene (C6H6). The reaction is indirect, initially forming a van der Waals complex that isomerizes below the energy of the reactants and eventually forming phenyl oxoborane by hydrogen emission in an overall exoergic radical-hydrogen atom exchange mechanism.
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Alagia M, Aquilanti V, Ascenzi D, Balucani N, Cappelletti D, Cartechini L, Casavecchia P, Pirani F, Sanchini G, Volpi GG. Magnetic Analysis of Supersonic Beams of Atomic Oxygen, Nitrogen, and Chlorine Generated from a Radio-Frequency Discharge. Isr J Chem 2013. [DOI: 10.1002/ijch.199700038] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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49
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Parker DSN, Balucani N, Stranges D, Kaiser RI, Mebel A. A crossed beam and ab initio investigation on the formation of boronyldiacetylene (HCCCC11BO; X1Σ+) via the reaction of the boron monoxide radical (11BO; X2Σ+) with diacetylene (C4H2; X1Σg(+)). J Phys Chem A 2013; 117:8189-98. [PMID: 23879375 DOI: 10.1021/jp405228f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction dynamics of the boron monoxide radical ((11)BO; X(2)Σ(+)) with diacetylene (C4H2; X(1)Σg(+)) were investigated at a nominal collision energy of 17.5 kJ mol(-1) employing the crossed molecular beam technique and supported by ab initio and statistical (RRKM) calculations. The reaction is governed by indirect (complex forming) scattering dynamics with the boron monoxide radical adding with its boron atom to the carbon-carbon triple bond of the diacetylene molecule at one of the terminal carbon atoms without entrance barrier. This leads to a doublet radical intermediate (C4H2(11)BO), which undergoes unimolecular decomposition through hydrogen atom emission from the C1 carbon atom via a tight exit transition state located about 18 kJ mol(-1) above the separated products. This process forms the hitherto elusive boronyldiacetylene molecule (HCCCC(11)BO; X(1)Σ(+)) in a bimolecular gas phase reaction under single collision conditions. The overall reaction was determined to be exoergic by 62 kJ mol(-1). The reaction dynamics are compared to the isoelectronic diacetylene (C4H2; X(1)Σg(+))-cyano radical (CN; X(2)Σ(+)) system studied previously in our group. The characteristics of boronyl-diacetylene and the boronyldiacetylene molecule (HCCCC(11)BO; X(1)Σ(+)) as well as numerous intermediates are reported for the first time.
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Leonori F, Skouteris D, Petrucci R, Casavecchia P, Rosi M, Balucani N. Combined crossed beam and theoretical studies of the C(1D) + CH4 reaction. J Chem Phys 2013; 138:024311. [DOI: 10.1063/1.4773579] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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