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Wang J, Kleimeier NF, Johnson RN, Gozem S, Abplanalp MJ, Turner AM, Marks JH, Kaiser RI. Photochemically triggered cheletropic formation of cyclopropenone (c-C 3H 2O) from carbon monoxide and electronically excited acetylene. Phys Chem Chem Phys 2022; 24:17449-17461. [PMID: 35713004 DOI: 10.1039/d2cp01978g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
For more than half a century, pericyclic reactions have played an important role in advancing our fundamental understanding of cycloadditions, sigmatropic shifts, group transfer reactions, and electrocyclization reactions. However, the fundamental mechanisms of photochemically activated cheletropic reactions have remained contentious. Here we report on the simplest cheletropic reaction: the [2+1] addition of ground state 18O-carbon monoxide (C18O, X1Σ+) to D2-acetylene (C2D2) photochemically excited to the first excited triplet (T1), second excited triplet (T2), and first excited singlet state (S1) at 5 K, leading to the formation of D2-18O-cyclopropenone (c-C3D218O). Supported by quantum-chemical calculations, our investigation provides persuasive testimony on stepwise cheletropic reaction pathways to cyclopropenone via excited state dynamics involving the T2 (non-adiabatic) and S1 state (adiabatic) of acetylene at 5 K, while the T1 state energetically favors an intermediate structure that directly dissociates after relaxing to the ground state. The agreement between experiments in low temperature ices and the excited state calculations signifies how photolysis experiments coupled with theoretical calculations can untangle polyatomic reactions with relevance to fundamental physical organic chemistry at the molecular level, thus affording a versatile strategy to unravel exotic non-equilibrium chemistries in cyclic, aromatic organics. Distinct from traditional radical-radical pathways leading to organic molecules on ice-coated interstellar nanoparticles (interstellar grains) in cold molecular clouds and star-forming regions, the photolytic formation of cyclopropenone as presented changes the perception of how we explain the formation of complex organics in the interstellar medium eventually leading to the molecular precursors of biorelevant molecules.
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Affiliation(s)
- Jia Wang
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - N Fabian Kleimeier
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Rebecca N Johnson
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA.
| | - Samer Gozem
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA.
| | - Matthew J Abplanalp
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Andrew M Turner
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Joshua H Marks
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA. .,W. M. Keck Research Laboratory in Astrochemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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Logdi R, Bag A, Tiwari AK. Competitive Reactivity of SO 2 and NO 2 with N-Heterocyclic Carbene: A Mechanistic Study. J Phys Chem A 2021; 125:5718-5725. [PMID: 34170129 DOI: 10.1021/acs.jpca.1c02466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent DFT based molecular engineering to obtain stable oxathiirane S-oxide derivatives evokes the recommencement of the use of carbenes for the sequestering of SO2, which has been kept separate so far. Carbene is one of the key chemicals for the sequestering of various premier greenhouse gases like CO2, CO, N2O, etc. In this respect, a comparative study of the reactivity of carbenes with variant greenhouse gases is highly demanding. The present investigation is engrossed in the comparative reactivity of SO2 and NO2 with carbenes. All three selected carbenes are highly susceptible to SO2 and NO2. Through an immaculate mechanistic study, we are able to corroborate that the end product of the carbene-SO2 reaction is an adduct which has a preferable structure having a six-membered ring with hydrogen bonding instead of ketone and SO with higher thermodynamic stability than the corresponding oxathiirane S-oxide derivative. Carbene reacts with NO2 to form a stable carbene N, N-dioxide derivative which forms vibrationally excited oxaziridine N-oxide which rapidly dissociates to form a ketone derivative. The formation of carbene S, S-dioxide and carbene N, N-dioxide is a barrierless process. The dissociation of oxaziridene N-oxide is also a barrierless process.
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Affiliation(s)
- Ratan Logdi
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, 741246 West-Bengal, India
| | - Arijit Bag
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, 741246 West-Bengal, India
| | - Ashwani K Tiwari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, 741246 West-Bengal, India
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