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Mancini L, Vanuzzo G, Recio P, Caracciolo A, Faginas-Lago N, Rosi M, Casavecchia P, Balucani N. Unveiling the Reaction Mechanism of the N( 2D) + Pyridine Reaction: Ring-Contraction versus 7-Membered-Ring Formation Channels. J Phys Chem A 2024; 128:7177-7194. [PMID: 39141013 DOI: 10.1021/acs.jpca.4c02924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
Despite the relevance of the reactions of the prototypical nitrogen-containing six-membered aromatic molecule (N-heterocyclic) of pyridine (C6H5N) in environmental science, astrochemistry, planetary science, prebiotic chemistry, and materials science, few experimental/theoretical studies exist on the bimolecular reactions involving pyridine and neutral atomic/molecular radicals. We report a combined experimental and theoretical study on the elementary reaction of pyridine with excited nitrogen atoms, N(2D), aimed at providing information about the primary reaction products and their branching fractions (BFs). From previous crossed molecular beam (CMB) experiments with mass-spectrometric detection and present synergistic calculations of the reactive potential energy surface (PES) and product BFs we have unveiled the reaction mechanism. It is found that the reaction proceeds via N(2D) barrierless addition to pyridine that, via bridged intermediates followed by N atom "sliding" into the ring, leads to 7-membered-ring structures. They further evolve, mainly via ring-contraction mechanisms toward 5-membered-ring radical products and, to a smaller extent, via H-displacement mechanisms toward 7-membered-ring isomeric products and their isomers. Using the theoretical statistical estimates, an improved fit of the experimental data previously reported has been obtained, leading to the following results for the dominant product channels: C4H4N (pyrrolyl) + HCN (BF = 0.61 ± 0.20), C3H3N2 (1H-imidazolyl/1H-pyrazolyl) + C2H2 (BF = 0.11 ± 0.06), and C5H4N2 (7-membered-ring molecules or pyrrole carbonitriles) + H (BF = 0.28 ± 0.10). The ring-contraction product channels C4H4N (pyrrolyl) + HCN, C3H3N2 (1H-imidazolyl) + C2H2, C3H3N2 (1H-pyrazolyl) + C2H2, and C5H5 (cyclopentadienyl) + N2 have statistical BFs of 0.54, 0.09, 0.11, and 0.07, respectively. Among the H-displacement channels, the cyclic-CHCHCHCHNCN + H channel and cyclic-CHCHCHCHCN2 + H are theoretically predicted to have a comparable BF (0.07 and 0.06, respectively), while the other isomeric 7-membered-ring molecule + H channel has a BF of 0.03. Pyrrole-carbonitriles and 1H-ethynyl-1H-imidazole (+ H) isomeric channels have an overall BF of 0.03. Implications for the chemistry of Saturn's moon Titan and prebiotic chemistry, as well as for understanding the N-doping of graphene or carbon nanotubes, are noted.
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Affiliation(s)
- Luca Mancini
- Dipartimento di Chimica Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Gianmarco Vanuzzo
- Dipartimento di Chimica Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Pedro Recio
- Dipartimento di Chimica Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Adriana Caracciolo
- Dipartimento di Chimica Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Noelia Faginas-Lago
- Dipartimento di Chimica Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
- Master-Tec Srl, 06128 Perugia, Italy
| | - Marzio Rosi
- Dipartimento di Ingegneria Civile e Ambientale, Università degli Studi di Perugia, 06125 Perugia, Italy
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), 06123 Perugia, Italy
| | - Piergiorgio Casavecchia
- Dipartimento di Chimica Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta" (CNR-SCITEC), 06123 Perugia, Italy
| | - Nadia Balucani
- Dipartimento di Chimica Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
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Vanuzzo G, Caracciolo A, Minton TK, Balucani N, Casavecchia P, de Falco C, Baggioli A, Cavallotti C. Crossed-Beam and Theoretical Studies of the O( 3P, 1D) + Benzene Reactions: Primary Products, Branching Fractions, and Role of Intersystem Crossing. J Phys Chem A 2021; 125:8434-8453. [PMID: 34533308 PMCID: PMC8488941 DOI: 10.1021/acs.jpca.1c06913] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Reliable modeling
of hydrocarbon oxidation relies critically on
knowledge of the branching fractions (BFs) as a function of temperature
(T) and pressure (p) for the products
of the reaction of the hydrocarbon with atomic oxygen in its ground
state, O(3P). During the past decade, we have performed
in-depth investigations of the reactions of O(3P) with
a variety of small unsaturated hydrocarbons using the crossed molecular
beam (CMB) technique with universal mass spectrometric
(MS) detection and time-of-flight (TOF) analysis, combined with synergistic
theoretical calculations of the relevant potential energy surfaces
(PESs) and statistical computations of product BFs, including intersystem
crossing (ISC). This has allowed us to determine the primary products,
their BFs, and extent of ISC to ultimately provide theoretical channel-specific
rate constants as a function of T and p. In this work, we have extended this approach to the oxidation of
one of the most important species involved in the combustion of aromatics:
the benzene (C6H6) molecule. Despite extensive
experimental and theoretical studies on the kinetics and dynamics
of the O(3P) + C6H6 reaction, the
relative importance of the C6H5O (phenoxy) +
H open-shell products and of the spin-forbidden C5H6 (cyclopentadiene) + CO and phenol adduct closed-shell products
are still open issues, which have hampered the development of reliable
benzene combustion models. With the CMB technique, we have investigated
the reaction dynamics of O(3P) + benzene at a collision
energy (Ec) of 8.2 kcal/mol, focusing
on the occurrence of the phenoxy + H and spin-forbidden C5H6 + CO and phenol channels in order to shed further light
on the dynamics of this complex and important reaction, including
the role of ISC. Concurrently, we have also investigated the reaction
dynamics of O(1D) + benzene at the same Ec. Synergistic high-level electronic structure calculations
of the underlying triplet/singlet PESs, including nonadiabatic couplings,
have been performed to complement and assist the interpretation of
the experimental results. Statistical (RRKM)/master equation (ME)
computations of the product distribution and BFs on these PESs, with
inclusion of ISC, have been performed and compared to experiment.
In light of the reasonable agreement between the CMB experiment, literature
kinetic experimental results, and theoretical predictions for the
O(3P) + benzene reaction, the so-validated computational
methodology has been used to predict (i) the BF between the C6H5O + H and C5H6 + CO channels
as a function of collision energy and temperature (at 0.1 and 1 bar),
showing that their increase progressively favors radical (phenoxy
+ H)-forming over molecule (C5H6 + CO and phenol
stabilization)-forming channels, and (ii) channel-specific rate constants
as a function of T and p, which
are expected to be useful for improved combustion models.
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Affiliation(s)
- Gianmarco Vanuzzo
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Adriana Caracciolo
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Timothy K Minton
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Nadia Balucani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Piergiorgio Casavecchia
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, 06123 Perugia, Italy
| | - Carlo de Falco
- MOX - Modellistica e Calcolo Scientifico, Dipartimento di Matematica, Politecnico di Milano, 20133 Milano, Italy
| | - Alberto Baggioli
- Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, 20131 Milano, Italy
| | - Carlo Cavallotti
- Dipartimento di Chimica, Materiali e Ingegneria Chimica, Politecnico di Milano, 20131 Milano, Italy
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Cavallotti C, De Falco C, Pratali Maffei L, Caracciolo A, Vanuzzo G, Balucani N, Casavecchia P. Theoretical Study of the Extent of Intersystem Crossing in the O( 3P) + C 6H 6 Reaction with Experimental Validation. J Phys Chem Lett 2020; 11:9621-9628. [PMID: 33125250 PMCID: PMC8016199 DOI: 10.1021/acs.jpclett.0c02866] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 10/22/2020] [Indexed: 05/30/2023]
Abstract
The extent of intersystem crossing in the O(3P) + C6H6 reaction, a prototypical system for spin-forbidden reactions in oxygenated aromatic molecules, is theoretically evaluated for the first time. Calculations are performed using nonadiabatic transition-state theory coupled with stochastic master equation simulations and Landau-Zener theory. It is found that the dominant intersystem crossing pathways connect the T2 and S0 potential energy surfaces through at least two distinct minimum-energy crossing points. The calculated channel-specific rate constants and intersystem crossing branching fractions differ from previous literature estimates and provide valuable kinetic data for the investigation of benzene and polycyclic aromatic hydrocarbons oxidation in interstellar, atmospheric, and combustion conditions. The theoretical results are supported by crossed molecular beam experiments with electron ionization mass-spectrometric detection and time-of-flight analysis at 8.2 kcal/mol collision energy. This system is a suitable benchmark for theoretical and experimental studies of intersystem crossing in aromatic species.
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Affiliation(s)
- Carlo Cavallotti
- Dipartimento
di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, 20131 Milano, Italy
| | - Carlo De Falco
- Dipartimento
di Matematica, Politecnico di Milano, 20131 Milano, Italy
| | - Luna Pratali Maffei
- Dipartimento
di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, 20131 Milano, Italy
| | - Adriana Caracciolo
- Laboratory
of Molecular Processes in Combustion, Department of Chemistry, Biology
and Biotechnologies, University of Perugia, 06123 Perugia, Italy
| | - Gianmarco Vanuzzo
- Laboratory
of Molecular Processes in Combustion, Department of Chemistry, Biology
and Biotechnologies, University of Perugia, 06123 Perugia, Italy
| | - Nadia Balucani
- Laboratory
of Molecular Processes in Combustion, Department of Chemistry, Biology
and Biotechnologies, University of Perugia, 06123 Perugia, Italy
| | - Piergiorgio Casavecchia
- Laboratory
of Molecular Processes in Combustion, Department of Chemistry, Biology
and Biotechnologies, University of Perugia, 06123 Perugia, Italy
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Badran I, Nassar NN, Marei NN, Hassan A. Theoretical and thermogravimetric study on the thermo-oxidative decomposition of Quinolin-65 as an asphaltene model molecule. RSC Adv 2016. [DOI: 10.1039/c6ra07761g] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this study, the thermal oxidation of an asphaltene model molecule, Quinolin-65, was investigated using the density functional theory (DFT) and the second-order Møller–Plesset (MP2) perturbation theory.
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Affiliation(s)
- Ismail Badran
- Department of Chemistry
- An-Najah National University
- Nablus
- Palestine
| | - Nashaat N. Nassar
- Department of Chemical and Petroleum Engineering
- University of Calgary
- 2500 University Street NW
- Calgary
- Canada T2N 1N4
| | - Nedal N. Marei
- Department of Chemical and Petroleum Engineering
- University of Calgary
- 2500 University Street NW
- Calgary
- Canada T2N 1N4
| | - Azfar Hassan
- Department of Chemical and Petroleum Engineering
- University of Calgary
- 2500 University Street NW
- Calgary
- Canada T2N 1N4
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Scapinello M, Martini LM, Tosi P, Maranzana A, Tonachini G. Molecular growth of PAH-like systems induced by oxygen species: experimental and theoretical study of the reaction of naphthalene with HO (2Π3/2), O (3P), and O2 (3Σ−g). RSC Adv 2015. [DOI: 10.1039/c5ra05129k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
To assess if reactions with oxygen species can induce a mass increase of polycyclic aromatic hydrocarbons, we exposed naphthalene molecules to an oxidative gas flow containing the radicals H and HO (2Π3/2) and the diradicals O (3P) and O2 (3Σ−g).
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Affiliation(s)
| | | | - Paolo Tosi
- Dipartimento di Fisica
- Università di Trento
- Trento
- Italy
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Huang YH, Chen JD, Hsu KH, Chu LK, Lee YP. Transient Infrared Absorption Spectra of Reaction Intermediates Detected with a Step-scan Fourier-transform Infrared Spectrometer. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.201300415] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Tsuji M, Kawahara T, Kamo N, Miyano M. Photochemical Removal of Benzene Using 172 nm Xe2Excimer Lamp in N2/O2Mixtures at Atmospheric Pressure. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2010. [DOI: 10.1246/bcsj.20090335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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