1
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Richardson JO. Nonadiabatic Tunneling in Chemical Reactions. J Phys Chem Lett 2024; 15:7387-7397. [PMID: 38995660 DOI: 10.1021/acs.jpclett.4c01098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
Quantum tunneling can have a dramatic effect on chemical reaction rates. In nonadiabatic reactions such as electron transfers or spin crossovers, nuclear tunneling effects can be even stronger than for adiabatic proton transfers. Ring-polymer instanton theory enables molecular simulations of tunneling in full dimensionality and has been shown to be far more reliable than commonly used separable approximations. First-principles instanton calculations predict significant nonadiabatic tunneling of heavy atoms even at room temperature and give excellent agreement with experimental measurements for the intersystem crossing of two nitrenes in cryogenic matrix isolation, the spin-forbidden relaxation of photoexcited thiophosgene in the gas phase, and singlet oxygen deactivation in water at ambient conditions. Finally, an outlook of further theoretical developments is discussed.
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Affiliation(s)
- Jeremy O Richardson
- Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
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2
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Lu B, Jiang J, Wang L, Jupp AR, Goicoechea JM, Liu S, Li Z, Zhou M, Zeng X. Carbamoylphosphinidene: A Phosphorus Analogue of Carbonyl Nitrene. J Am Chem Soc 2024; 146:18699-18705. [PMID: 38943601 DOI: 10.1021/jacs.4c06016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2024]
Abstract
Carbonyl nitrenes are versatile intermediates that have been extensively characterized; however, their phosphorus analogues remain largely unknown. Herein, we report the observation of a rare example of carbonyl phosphinidene NH2C(O)P, which was generated through the photolytic (193 nm) dehydrogenation of phosphinecarboxamide (NH2C(O)PH2) in a solid N2-matrix at 12 K. The characterization of NH2C(O)P in the triplet ground state with matrix-isolation IR and ultraviolet-visible (UV-vis) spectroscopy is supported by comprehensive isotope labeling experiments (D and 15N) and quantum chemical calculations. Upon visible-light irradiation at 680 nm, NH2C(O)P inserts into dihydrogen by the reformation of NH2C(O)PH2 with concomitant isomerization to the more stable aminophosphaketene (NH2PCO). Additionally, the photoisomerization of NH2C(O)PH2 to NH2C(OH) = PH along with decomposition by yielding hydrogen-bonded complexes HNCO···PH3 and HPCO···NH3 has been observed in the matrix.
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Affiliation(s)
- Bo Lu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Junjie Jiang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Lina Wang
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Andrew R Jupp
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
| | - Jose M Goicoechea
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
- Department of Chemistry, Indiana University, 800 East Kirkwood Ave., Bloomington, Indiana 47405, United States
| | - Shihua Liu
- LIFM, IGCME, School of Chemistry, Sun Yat-Sen University, 510006 Guangzhou, China
| | - Zhongshu Li
- LIFM, IGCME, School of Chemistry, Sun Yat-Sen University, 510006 Guangzhou, China
| | - Mingfei Zhou
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 200433 Shanghai, China
| | - Xiaoqing Zeng
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, 200433 Shanghai, China
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3
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Prado Merini M, Schleif T, Sander W. Heavy-Atom Tunneling in Bicyclo[4.1.0]hepta-2,4,6-trienes. Angew Chem Int Ed Engl 2023; 62:e202309717. [PMID: 37698374 DOI: 10.1002/anie.202309717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/13/2023]
Abstract
Heavy-atom tunneling limits the lifetime and observability of bicyclo[4.1.0]hepta-2,4,6-triene, a key intermediate in the rearrangement of phenylcarbene. Bicyclo[4.1.0]hepta-2,4,6-triene had been proposed as the primary intermediate of the rearrangement of phenylcarbene, but despite many efforts evaded its characterization even in cryogenic matrices. By introducing fluorine substituents into the ortho-positions of the phenyl ring of phenylcarbene, the highly strained cyclopropene 1,5-difluorobicyclo[4.1.0]hepta-2,4,6-triene becomes stable enough to be characterized in argon matrices. However, even at 3 K this cyclopropene is only metastable and rearranges via heavy-atom tunneling to the corresponding cycloheptatetraene. Calculations suggest that fluorination is necessary to slow down the tunneling rearrangement of the bicycloheptatriene. The parent bicycloheptatriene rapidly rearranges via heavy-atom tunneling and therefore cannot be detected under matrix isolation conditions.
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Affiliation(s)
- Melania Prado Merini
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Universitätsstraße 150, 44801, Bochum, Germany
| | - Tim Schleif
- Department of Chemistry, Yale University, 225 Prospect St., New Haven, CT 06520, USA
| | - Wolfram Sander
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Universitätsstraße 150, 44801, Bochum, Germany
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4
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Fang W, Heller ER, Richardson JO. Competing quantum effects in heavy-atom tunnelling through conical intersections. Chem Sci 2023; 14:10777-10785. [PMID: 37829019 PMCID: PMC10566476 DOI: 10.1039/d3sc03706a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 09/07/2023] [Indexed: 10/14/2023] Open
Abstract
Thermally activated chemical reactions are typically understood in terms of overcoming potential-energy barriers. However, standard rate theories break down in the presence of a conical intersection (CI) because these processes are inherently nonadiabatic, invalidating the Born-Oppenheimer approximation. Moreover, CIs give rise to intricate nuclear quantum effects such as tunnelling and the geometric phase, which are neglected by standard trajectory-based simulations and remain largely unexplored in complex molecular systems. We present new semiclassical transition-state theories based on an extension of golden-rule instanton theory to describe nonadiabatic tunnelling through CIs and thus provide an intuitive picture for the reaction mechanism. We apply the method in conjunction with first-principles electronic-structure calculations to the electron transfer in the bis(methylene)-adamantyl cation. Our study reveals a strong competition between heavy-atom tunnelling and geometric-phase effects.
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Affiliation(s)
- Wei Fang
- Department of Chemistry, Fudan University Shanghai 200438 P. R. China
- Department of Chemistry and Applied Biosciences, ETH Zürich 8093 Zürich Switzerland
| | - Eric R Heller
- Department of Chemistry and Applied Biosciences, ETH Zürich 8093 Zürich Switzerland
| | - Jeremy O Richardson
- Department of Chemistry and Applied Biosciences, ETH Zürich 8093 Zürich Switzerland
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5
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Ma Z, Yan Z, Li X, Chung LW. Quantum Tunneling in Reactions Modulated by External Electric Fields: Reactivity and Selectivity. J Phys Chem Lett 2023; 14:1124-1132. [PMID: 36705472 DOI: 10.1021/acs.jpclett.2c03461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Quantum tunneling and external electric fields (EEFs) can promote some reactions. However, the synergetic effect of an EEF on a tunneling-involving reaction and its temperature-dependence is not very clear. In this study, we extensively investigated how EEFs affect three reactions that involve hydrogen- or (ground- and excited-state) carbon-tunneling using reliable DFT, DLPNO-CCSD(T1), and variational transition-state theory methods. Our study revealed that oriented EEFs can significantly reduce the barrier and corresponding barrier width (and vice versa) through more electrostatic stabilization in transition states. These EEF effects enhance the nontunneling and tunneling-involving rates. Such EEF effects also decrease the crossover temperatures and quantum tunneling contribution, albeit with lower and thinner barriers. Moreover, EEFs can modulate and switch on/off the tunneling-driven 1,2-H migration of hydroxycarbenes under cryogenic conditions. Furthermore, our study predicts for the first time that EEF/tunneling synergy can control the chemo- or site-selectivity of one molecule bearing two similar/same reactive sites.
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Affiliation(s)
- Zhifeng Ma
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen 518055, P. R. China
| | - Zeyin Yan
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen 518055, P. R. China
| | - Xin Li
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen 518055, P. R. China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, 1088 Xueyuan Avenue, Shenzhen 518055, P. R. China
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6
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Tran Q, Sengupta A, Houk KN. Probative Evidence and Quantitative Energetics for the Unimolecular Mechanism of the 1,5-Sigmatropic Hydrogen Shift of Cyclopentadiene. J Org Chem 2022; 87:14995-15000. [PMID: 36318665 DOI: 10.1021/acs.joc.2c02145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
While the 1,5-sigmatropic hydrogen shift in cyclopentadiene is generally thought to be a unimolecular pericyclic reaction, Yamabe proposed a more complex bimolecular mechanism proceeding through the exo dimer of cyclopentadiene. DFT computations by Yamabe were claimed to show that the bimolecular mechanism was kinetically more favorable than the unimolecular mechanism. Reinvestigation of the unimolecular concerted mechanism and Yamabe's bimolecular mechanism with ωB97X-D and DLPNO-CCSD(T) calculations demonstrates a 25 kcal/mol preference for the unimolecular mechanism relative to the bimolecular mechanism. While Yamabe's calculations were performed with the less accurate B3LYP functional, the incorrect conclusion was the result of a different error discovered here. We have also computed corrections for tunneling that result in computed activation barriers within 1.5 kcal/mol of the experimental values.
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Affiliation(s)
- Quan Tran
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Arkajyoti Sengupta
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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7
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Schleif T. Transformations of Strained Three-Membered Rings a Common, Yet Overlooked, Motif in Heavy-Atom Tunneling Reactions. Chemistry 2022; 28:e202201775. [PMID: 35762788 PMCID: PMC9804509 DOI: 10.1002/chem.202201775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Indexed: 01/05/2023]
Abstract
Quantum mechanical tunneling has long been recognized as an important phenomenon when considering transformations dominated by a lightweight hydrogen atom. Tunneling of heavier atoms like carbon, initially dismissed as negligible, has seen a quickly increasing number of computationally predicted and/or experimentally confirmed examples over the last decade, thus highlighting its importance for a wide variety of reactions. However, no common structural motif has been pointed out within these seemingly unconnected examples, strongly limiting the predictability of the impact of heavy-atom tunneling on a given reaction. This Concept article will provide this perspective and showcase how the recognition of the formation and cleavage of three-membered rings as common motif can inform the prediction of and research into heavy-atom tunneling reactions.
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Affiliation(s)
- Tim Schleif
- Lehrstuhl für Organische Chemie IIRuhr-Universität Bochum44780BochumGermany,Present address: Sterling Chemistry LaboratoryYale UniversityNew HavenCT 06520USA
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8
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Heller ER, Richardson JO. Heavy‐Atom Quantum Tunnelling in Spin Crossovers of Nitrenes**. Angew Chem Int Ed Engl 2022; 61:e202206314. [PMID: 35698730 PMCID: PMC9540336 DOI: 10.1002/anie.202206314] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Indexed: 01/01/2023]
Abstract
We simulate two recent matrix‐isolation experiments at cryogenic temperatures, in which a nitrene undergoes spin crossover from its triplet state to a singlet state via quantum tunnelling. We detail the failure of the commonly applied weak‐coupling method (based on a linear approximation of the potentials) in describing these deep‐tunnelling reactions. The more rigorous approach of semiclassical golden‐rule instanton theory in conjunction with double‐hybrid density‐functional theory and multireference perturbation theory does, however, provide rate constants and kinetic isotope effects in good agreement with experiment. In addition, these calculations locate the optimal tunnelling pathways, which provide a molecular picture of the reaction mechanism. The reactions involve substantial heavy‐atom quantum tunnelling of carbon, nitrogen and oxygen atoms, which unexpectedly even continues to play a role at room temperature.
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Affiliation(s)
- Eric R. Heller
- Laboratory of Physical Chemistry ETH Zürich 8093 Zürich Switzerland
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9
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Wu Z, Zeng X. Curtius-Type Rearrangement of Sulfinyl Azides: A Matrix Isolation and Computational Study. J Phys Chem A 2022; 126:4367-4375. [PMID: 35771242 DOI: 10.1021/acs.jpca.2c02469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The highly unstable methyl sulfinyl azide, CH3S(O)N3, has been synthesized and characterized for the first time. In the gas phase, CH3S(O)N3 decomposes quickly at room temperature (300 K) with an estimated half-life (t1/2) of 7 min. Upon irradiation at 266 nm in cryogenic Ar (10 K) and Ne (3 K) matrices, the azide extrudes molecular nitrogen by yielding the novel sulfinyl nitrene intermediate CH3S(O)N in the closed-shell singlet ground state, which has been characterized with matrix-isolation IR and UV-vis spectroscopy. Prolonged irradiation at 266 nm causes Curtius rearrangement of the nitrene to form N-sulfinylamine CH3NSO and S-nitrosothiol CH3SNO. By high-vacuum flash pyrolysis (HVFP) at 800 K, CH3S(O)N3 also decomposes and furnishes CH3S(O)N with minor fragmentation products HNSO and CH2 in the gas phase. A similar photo-induced Curtius-type rearrangement of trifluoromethyl sulfinyl azide CF3S(O)N3 to CF3NSO and CF3SNO has also been observed in matrices. According to the theoretical calculations at the CCSD(T)/aug-cc-pVTZ//B3LYP/6-311++G (3df,3pd) level of theory, the rearrangement of CH3S(O)N3 prefers a stepwise pathway by initial formation of the nitrene intermediate CH3S(O)N. In line with the thermal persistence of CH3S(O)N in the gas phase, the barriers for its subsequent rearrangement are higher than 30 kcal mol-1.
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Affiliation(s)
- Zhuang Wu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai 200437, China
| | - Xiaoqing Zeng
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai 200437, China
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10
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Heller ER, Richardson JO. Heavy‐Atom Quantum Tunnelling in Spin Crossovers of Nitrenes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Eric R Heller
- Eidgenossische Technische Hochschule Zurich Lab. Physical Chemistry SWITZERLAND
| | - Jeremy O Richardson
- Eidgenössische Technische Hochschule Zürich Lab. Physical Chemistry Vladimir-Prelog-Weg 2 8093 Zurich SWITZERLAND
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11
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Synthesis and macrocyclization-induced emission enhancement of benzothiadiazole-based macrocycle. Nat Commun 2022; 13:2850. [PMID: 35606365 PMCID: PMC9126912 DOI: 10.1038/s41467-022-30121-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 04/18/2022] [Indexed: 12/29/2022] Open
Abstract
We presented an effective and universal strategy for the improvement of luminophore’s solid-state emission, i.e., macrocyclization-induced emission enhancement (MIEE), by linking luminophores through C(sp3) bridges to give a macrocycle. Benzothiadiazole-based macrocycle (BT-LC) has been synthesized by a one-step condensation of the monomer 4,7-bis(2,4-dimethoxyphenyl)−2,1,3-benzothiadiazole (BT-M) with paraformaldehyde, catalyzed by Lewis acid. In comparison with the monomer, macrocycle BT-LC produces much more intense fluorescence in the solid state (ΦPL = 99%) and exhibits better device performance in the application of OLEDs. Single-crystal analysis and theoretical simulations reveal that the monomer can return to the ground state through a minimum energy crossing point (MECPS1/S0), resulting in the decrease of fluorescence efficiency. For the macrocycle, its inherent structural rigidity prohibits this non-radiative relaxation process and promotes the radiative relaxation, therefore emitting intense fluorescence. More significantly, MIEE strategy has good universality that several macrocycles with different luminophores also display emission improvement. Organic luminescent materials attract attention due to their wide application range, but many organic luminogens suffer from severe quenching effect in the aggregate state. Here, the authors demonstrate a macrocyclization induced emission enhancement by linking luminophores through methylene bridges to give a macrocycle.
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12
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Heller ER, Richardson JO. Spin Crossover of Thiophosgene via Multidimensional Heavy-Atom Quantum Tunneling. J Am Chem Soc 2021; 143:20952-20961. [PMID: 34846871 DOI: 10.1021/jacs.1c10088] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The spin-crossover reaction of thiophosgene has drawn broad attention from both experimenters and theoreticians as a prime example of radiationless intramolecular decay via intersystem crossing. Despite multiple attempts over 20 years, theoretical predictions have typically been orders of magnitude in error relative to the experimentally measured triplet lifetime. We address the T1 → S0 transition by the first application of semiclassical golden-rule instanton theory in conjunction with on-the-fly electronic-structure calculations based on multireference perturbation theory. Our first-principles approach provides excellent agreement with the experimental rates. This was only possible because instanton theory goes beyond previous methods by locating the optimal tunneling pathway in full dimensionality and thus captures "corner cutting" effects. Since the reaction is situated in the Marcus inverted regime, the tunneling mechanism can be interpreted in terms of two classical trajectories, one traveling forward and one backward in imaginary time, which are connected by particle-antiparticle creation and annihilation events. The calculated mechanism indicates that the spin crossover is sped up by many orders of magnitude due to multidimensional quantum tunneling of the carbon atom even at room temperature.
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Affiliation(s)
- Eric R Heller
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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13
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Schleif T, Sander W. Photolysis and thermolysis of (iodomethyl)cyclopropane: Rapid ring opening of cyclopropylcarbinyl via heavy‐atom tunneling? J PHYS ORG CHEM 2021. [DOI: 10.1002/poc.4295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Tim Schleif
- Lehrstuhl für Organische Chemie II Ruhr‐Universität Bochum Bochum Germany
| | - Wolfram Sander
- Lehrstuhl für Organische Chemie II Ruhr‐Universität Bochum Bochum Germany
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14
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Kobayashi Y, Masakado S, Murai T, Hamada S, Furuta T, Takemoto Y. A bench-stable N-trifluoroacetyl nitrene equivalent for a simple synthesis of 2-trifluoromethyl oxazoles. Org Biomol Chem 2021; 19:6628-6632. [PMID: 34282812 DOI: 10.1039/d1ob00947h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
ortho-Nitro-substituted N-trifluoroacetyl imino-λ3-iodane is a bench-stable trifluoroacetyl nitrene precursor, in which intra- and intermolecular halogen bonding (XB) plays an important role. Potential synthetic applications of this novel precursor were explored.
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Affiliation(s)
- Yusuke Kobayashi
- Department of Pharmaceutical Chemistry, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto 607-8414, Japan.
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15
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Viegas LP, M. Nunes C, Fausto R. Spin-forbidden heavy-atom tunneling in the ring-closure of triplet cyclopentane-1,3-diyl. Phys Chem Chem Phys 2021; 23:5797-5803. [DOI: 10.1039/d1cp00076d] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The putative spin-forbidden heavy-atom tunneling process for the ring closure of cyclopentane-1,3-diyl at cryogenic temperatures is confirmed with calculations employing the weak-coupling formulation of nonadiabatic transition state theory.
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Affiliation(s)
- Luís P. Viegas
- University of Coimbra
- CQC
- Department of Chemistry
- 3004-535 Coimbra
- Portugal
| | - Cláudio M. Nunes
- University of Coimbra
- CQC
- Department of Chemistry
- 3004-535 Coimbra
- Portugal
| | - Rui Fausto
- University of Coimbra
- CQC
- Department of Chemistry
- 3004-535 Coimbra
- Portugal
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16
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17
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Nunes CM, Viegas LP, Wood SA, Roque JPL, McMahon RJ, Fausto R. Heavy‐Atom Tunneling Through Crossing Potential Energy Surfaces: Cyclization of a Triplet 2‐Formylarylnitrene to a Singlet 2,1‐Benzisoxazole. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Cláudio M. Nunes
- University of Coimbra CQC Department of Chemistry 3004-535 Coimbra Portugal
| | - Luís P. Viegas
- University of Coimbra CQC Department of Chemistry 3004-535 Coimbra Portugal
| | - Samuel A. Wood
- Department of Chemistry University of Wisconsin-Madison Madison WI 53706-1322 USA
| | - José P. L. Roque
- University of Coimbra CQC Department of Chemistry 3004-535 Coimbra Portugal
| | - Robert J. McMahon
- Department of Chemistry University of Wisconsin-Madison Madison WI 53706-1322 USA
| | - Rui Fausto
- University of Coimbra CQC Department of Chemistry 3004-535 Coimbra Portugal
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18
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Comment on “Computational evidence for sulfur atom tunneling in the ring flipping reaction of S4N4”. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137678] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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19
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Schleif T, Tatchen J, Rowen JF, Beyer F, Sanchez‐Garcia E, Sander W. Heavy-Atom Tunneling in Semibullvalenes: How Driving Force, Substituents, and Environment Influence the Tunneling Rates. Chemistry 2020; 26:10452-10458. [PMID: 32293763 PMCID: PMC7496793 DOI: 10.1002/chem.202001202] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Indexed: 12/21/2022]
Abstract
The Cope rearrangement of selectively deuterated isotopomers of 1,5-dimethylsemibullvalene 2 a and 3,7-dicyano-1,5-dimethylsemibullvalene 2 b were studied in cryogenic matrices. In both semibullvalenes the Cope rearrangement is governed by heavy-atom tunneling. The driving force for the rearrangements is the small difference in the zero-point vibrational energies of the isotopomers. To evaluate the effect of the driving force on the tunneling probability in 2 a and 2 b, two different pairs of isotopomers were studied for each of the semibullvalenes. The reaction rates for the rearrangement of 2 b in cryogenic matrices were found to be smaller than the ones of 2 a under similar conditions, whereas differences in the driving force do not influence the rates. Small curvature tunneling (SCT) calculations suggest that the reduced tunneling rate of 2 b compared to that of 2 a results from a change in the shape of the potential energy barrier. The tunneling probability of the semibullvalenes strongly depends on the matrix environment; however, for 2 a in a qualitatively different way than for 2 b.
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Affiliation(s)
- Tim Schleif
- Lehrstuhl für Organische Chemie IIRuhr-Universität Bochum47780BochumGermany
| | - Jörg Tatchen
- Computational BiochemistryUniversität Duisburg-Essen45117EssenGermany
| | - Julien F. Rowen
- Lehrstuhl für Organische Chemie IIRuhr-Universität Bochum47780BochumGermany
| | - Frederike Beyer
- Lehrstuhl für Organische Chemie IIRuhr-Universität Bochum47780BochumGermany
| | | | - Wolfram Sander
- Lehrstuhl für Organische Chemie IIRuhr-Universität Bochum47780BochumGermany
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20
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Nunes CM, Viegas LP, Wood SA, Roque JPL, McMahon RJ, Fausto R. Heavy‐Atom Tunneling Through Crossing Potential Energy Surfaces: Cyclization of a Triplet 2‐Formylarylnitrene to a Singlet 2,1‐Benzisoxazole. Angew Chem Int Ed Engl 2020; 59:17622-17627. [PMID: 32558100 DOI: 10.1002/anie.202006640] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Indexed: 11/05/2022]
Affiliation(s)
- Cláudio M. Nunes
- University of Coimbra CQC Department of Chemistry 3004-535 Coimbra Portugal
| | - Luís P. Viegas
- University of Coimbra CQC Department of Chemistry 3004-535 Coimbra Portugal
| | - Samuel A. Wood
- Department of Chemistry University of Wisconsin-Madison Madison WI 53706-1322 USA
| | - José P. L. Roque
- University of Coimbra CQC Department of Chemistry 3004-535 Coimbra Portugal
| | - Robert J. McMahon
- Department of Chemistry University of Wisconsin-Madison Madison WI 53706-1322 USA
| | - Rui Fausto
- University of Coimbra CQC Department of Chemistry 3004-535 Coimbra Portugal
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21
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Lu B, Qin Y, Lu Y, Liu Q, Zeng X. Acryloylnitrenes: Spectroscopic Characterization, Spin Multiplicities, and Rearrangement to Vinyl Isocyanates. J Phys Chem A 2020; 124:6319-6329. [PMID: 32660245 DOI: 10.1021/acs.jpca.0c04204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The simplest acryloylnitrene, CH2═CHC(O)N (1b), and two halogenated derivatives, CH2═CFC(O)N (2b) and CH2═CBrC(O)N (3b), were generated through the 266 nm laser photolysis of the corresponding azide precursors in solid N2-matrices at 15 K. The IR spectroscopic characterization of these new acylnitrenes is supported by 15N-labeling and quantum chemical calculations at the B3LYP/6-311++G(3df,3pd) level of theory. For the three nitrenes 1b, 2b, and 3b, two conformers exhibiting syn and anti configurations between the C═C and C═O bonds with respect to the C-C bonds have been identified. Consistent with the CBS-QB3 calculated singlet-triplet energy gaps (ΔEST < 0 kcal mol-1), the IR spectral analysis suggests that all these acryloylnitrenes adopt oxazirine-like structures with closed-shell singlet spin multiplicity. Upon subsequent green light (532 nm) irradiation, these acryloylnitrenes rearrange to form vinyl isocyanates CH2═CXNCO (X = H, F, Br), for which the IR spectra have also been obtained. According to the calculations on the α,β-fluorinated acryloylnitrenes at the CBS-QB3 level, their spin multiplicities can be switched from singlet CH2═CFC(O)N (ΔEST = -0.86 kcal mol-1) to triplet CF2═CFC(O)N (ΔEST = +0.61 kcal mol-1), whereas CFH═CFC(O)N is magnetically bistable due to a rather small ΔEST (+0.09 kcal mol-1).
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Affiliation(s)
- Bo Lu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China
| | - Yuanyuan Qin
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China
| | - Yan Lu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China
| | - Qian Liu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China
| | - Xiaoqing Zeng
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China.,Department of Chemistry, Fudan University, Shanghai 200433, China
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22
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Heavy-Atom Tunneling Processes during Denitrogenation of 2,3-Diazabicyclo[2.2.1]hept-2-ene and Ring Closure of Cyclopentane-1,3-diyl Diradical. Stereoselectivity in Tunneling and Matrix Effect. J Org Chem 2020; 85:8881-8892. [DOI: 10.1021/acs.joc.0c00763] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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23
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Castro C, Karney WL. Heavy‐Atom Tunneling in Organic Reactions. Angew Chem Int Ed Engl 2020; 59:8355-8366. [DOI: 10.1002/anie.201914943] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/03/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Claire Castro
- Department of Chemistry University of San Francisco 2130 Fulton St. San Francisco CA 94117 USA
| | - William L. Karney
- Department of Chemistry University of San Francisco 2130 Fulton St. San Francisco CA 94117 USA
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24
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Affiliation(s)
- Claire Castro
- Department of Chemistry University of San Francisco 2130 Fulton St. San Francisco CA 94117 USA
| | - William L. Karney
- Department of Chemistry University of San Francisco 2130 Fulton St. San Francisco CA 94117 USA
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25
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Takemoto Y, Masakado S, Kobayashi Y. Photo-Irradiation-Promoted Aminoetherification of Glycals with N-Acyliminoiodinane and Alcohols. HETEROCYCLES 2020. [DOI: 10.3987/com-19-s(f)25] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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26
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Nunes CM, Eckhardt AK, Reva I, Fausto R, Schreiner PR. Competitive Nitrogen versus Carbon Tunneling. J Am Chem Soc 2019; 141:14340-14348. [DOI: 10.1021/jacs.9b06869] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Cláudio M. Nunes
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - André K. Eckhardt
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Igor Reva
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Rui Fausto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Peter R. Schreiner
- Institute of Organic Chemistry, Justus Liebig University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
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27
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Liu Q, Qin Y, Lu Y, Wentrup C, Zeng X. Spectroscopic Characterization of Nicotinoyl and Isonicotinoyl Nitrenes and the Photointerconversion of 4-Pyridylnitrene with Diazacycloheptatetraene. J Phys Chem A 2019; 123:3793-3801. [PMID: 30978289 DOI: 10.1021/acs.jpca.9b01680] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recently, nicotinoyl nitrene (2) has been generated from the photodecomposition of nicotinoyl azide (1) and used as the key intermediate in probing nucleobase solvent accessibility inside cells. Following the 266 nm laser photolysis of nicotinoyl azide (1) and isonicotinoyl azide (5) in solid N2 matrices at 15 K, nicotinoyl nitrene (2) and isonicotinoyl nitrene (6) have now been identified by matrix-isolation infrared (IR) spectroscopy. Both aroyl nitrenes 2 and 6 adopt closed-shell singlet ground states stabilized by significant Nnitrene···O interactions, which is consistent with the spectroscopic analysis and calculations at the CBS-QB3 level of theory. Upon subsequent visible light irradiations, 2 (400 ± 20 nm) and 6 (532 nm) undergo rearrangement to pyridyl isocyanates 3 and 7. Further dissociation of 3 and 7 under 193 nm laser irradiation results in CO elimination and formation of ketenimines 12 and 13 via the ring opening of elusive pyridyl nitrenes 4 and 8, respectively. In addition to the IR spectroscopic identification of 8 in the triplet ground state, its reversible photointerconversion with ring expansion to diazacycloheptatetraene 9 has been observed directly. The spectroscopic identification of the nitrene intermediates was aided by calculations at the B3LYP/6-311++G(3df,3pd) level, and the mechanism for their generation in stepwise decompositions of the azides is discussed in the light of CBS-QB3 calculations.
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Affiliation(s)
- Qian Liu
- College of Chemistry, Chemical Engineering and Materials Science , Soochow University , 215123 Suzhou , China
| | - Yuanyuan Qin
- College of Chemistry, Chemical Engineering and Materials Science , Soochow University , 215123 Suzhou , China
| | - Yan Lu
- College of Chemistry, Chemical Engineering and Materials Science , Soochow University , 215123 Suzhou , China
| | - Curt Wentrup
- School of Chemistry and Molecular Biosciences , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Xiaoqing Zeng
- College of Chemistry, Chemical Engineering and Materials Science , Soochow University , 215123 Suzhou , China
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28
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Liu Q, Wan H, Lu Y, Lu B, Zeng X. Photodecomposition of 1H
-Pyrrole Carbonyl Azides: Direct Observation of Singlet 1H
-Pyrrole Carbonyl Nitrenes and Triplet 1H
-3-Pyrrylnitrene. European J Org Chem 2018. [DOI: 10.1002/ejoc.201800830] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Qian Liu
- College of Chemistry; Chemical Engineering and Materials Science; Soochow University; 215123 Suzhou China
| | - Huabin Wan
- College of Chemistry; Chemical Engineering and Materials Science; Soochow University; 215123 Suzhou China
| | - Yan Lu
- College of Chemistry; Chemical Engineering and Materials Science; Soochow University; 215123 Suzhou China
| | - Bo Lu
- College of Chemistry; Chemical Engineering and Materials Science; Soochow University; 215123 Suzhou China
| | - Xiaoqing Zeng
- College of Chemistry; Chemical Engineering and Materials Science; Soochow University; 215123 Suzhou China
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29
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Wentrup C. Carbenes and Nitrenes: Recent Developments in Fundamental Chemistry. Angew Chem Int Ed Engl 2018; 57:11508-11521. [DOI: 10.1002/anie.201804863] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Curt Wentrup
- School of Chemistry and Molecular BiosciencesThe University of Queensland Brisbane Qld 4072 Australia
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30
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Wentrup C. Carbene und Nitrene: Aktuelle Entwicklungen in der Grundlagenchemie. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201804863] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Curt Wentrup
- School of Chemistry and Molecular Biosciences; The University of Queensland; Brisbane Qld 4072 Australien
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31
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Abe M, Bégué D, Santos-Silva H, Dargelos A, Wentrup C. Direct Observation of an Imidoylnitrene: Photochemical Formation of PhC(=NMe)−N and Me−N from 1-Methyl-5-phenyltetrazole. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201712689] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Manabu Abe
- Department of Chemistry; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama, Higashi-Hiroshima Hiroshima 739-8526 Japan
| | - Didier Bégué
- Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux; Université de Pau et des Pays de l'Adour; 64000 Pau France
| | - Hugo Santos-Silva
- Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux; Université de Pau et des Pays de l'Adour; 64000 Pau France
| | - Alain Dargelos
- Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux; Université de Pau et des Pays de l'Adour; 64000 Pau France
| | - Curt Wentrup
- School of Chemistry and Molecular Biosciences; The University of Queensland; Brisbane Queensland 4072 Australia
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32
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Abe M, Bégué D, Santos-Silva H, Dargelos A, Wentrup C. Direct Observation of an Imidoylnitrene: Photochemical Formation of PhC(=NMe)−N and Me−N from 1-Methyl-5-phenyltetrazole. Angew Chem Int Ed Engl 2018; 57:3212-3216. [DOI: 10.1002/anie.201712689] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 01/17/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Manabu Abe
- Department of Chemistry; Graduate School of Science; Hiroshima University; 1-3-1 Kagamiyama, Higashi-Hiroshima Hiroshima 739-8526 Japan
| | - Didier Bégué
- Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux; Université de Pau et des Pays de l'Adour; 64000 Pau France
| | - Hugo Santos-Silva
- Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux; Université de Pau et des Pays de l'Adour; 64000 Pau France
| | - Alain Dargelos
- Institut Pluridisciplinaire de Recherche sur l'Environnement et les Matériaux; Université de Pau et des Pays de l'Adour; 64000 Pau France
| | - Curt Wentrup
- School of Chemistry and Molecular Biosciences; The University of Queensland; Brisbane Queensland 4072 Australia
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33
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Eckhardt AK, Gerbig D, Schreiner PR. Heavy Atom Secondary Kinetic Isotope Effect on H-Tunneling. J Phys Chem A 2018; 122:1488-1495. [DOI: 10.1021/acs.jpca.7b12118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- André K. Eckhardt
- Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring
17, 35392 Giessen, Germany
| | - Dennis Gerbig
- Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring
17, 35392 Giessen, Germany
| | - Peter R. Schreiner
- Institute of Organic Chemistry, Justus-Liebig University, Heinrich-Buff-Ring
17, 35392 Giessen, Germany
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34
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Lu Y, Li H, Abe M, Bégué D, Wan H, Deng G, Xu J, Liu K, Zeng X. Sulfamoyl nitrenes: singlet or triplet ground state? Chem Commun (Camb) 2018; 54:6136-6139. [DOI: 10.1039/c8cc03278e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two prototypical sulfamoyl nitrenes R2NS(O)2–N (R = H and Me) in the triplet state were generated via the closed-shell singlet state by passing a low-energy minimum energy crossing point (MECP).
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Affiliation(s)
- Yan Lu
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
- China
| | - Hongmin Li
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
- China
| | - Manabu Abe
- Department of Chemistry
- Graduate School of Science
- Hiroshima University
- Higashi-Hiroshima Hiroshima 739-8526
- Japan
| | - Didier Bégué
- Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux
- Universitéde Pau et des Pays de l’Adour
- Pau 64000
- France
| | - Huabin Wan
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
- China
| | - Guohai Deng
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
- China
| | - Jian Xu
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
- China
| | - Kun Liu
- College of Chemistry
- Tianjin Normal University
- Tianjin
- China
| | - Xiaoqing Zeng
- College of Chemistry
- Chemical Engineering and Materials Science
- Soochow University
- Suzhou 215123
- China
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