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Jayasekara GK, Antolini C, Smith MA, Jacoby DJ, Escolastico J, Girard N, Young BT, Hayes D. Mechanisms of the Cu(I)-Catalyzed Intermolecular Photocycloaddition Reaction Revealed by Optical and X-ray Transient Absorption Spectroscopies. J Am Chem Soc 2021; 143:19356-19364. [PMID: 34752703 DOI: 10.1021/jacs.1c07282] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The [2 + 2] photocycloaddition provides a simple, single-step route to cyclobutane moieties that would otherwise be disfavored or impossible due to ring strain and/or steric interactions. We have used a combination of optical and X-ray transient absorption spectroscopies to elucidate the mechanism of the Cu(I)-catalyzed intermolecular photocycloaddition reaction using norbornene and cyclohexene as model substrates. We find that for norbornene the reaction proceeds through an initial metal-to-ligand charge transfer (MLCT) state that persists for 18 ns before the metal returns to the monovalent oxidation state. The Cu K-edge spectrum continues to evolve until ∼5 μs and then remains unchanged for the 50 μs duration of the measurement, reflecting product formation and ligand dissociation. We hypothesize that the MLCT transition and reverse electron transfer serve to sensitize the triplet excited state of one of the norbornene ligands, which then dimerizes with the other to give the product. For the case of cyclohexene, however, we do not observe a charge transfer state following photoexcitation and instead find evidence for an increase in the metal-ligand bond strength that persists for several ns before product formation occurs. This is consistent with a mechanism in which ligand photoisomerization is the initial step, which was first proposed by Salomon and Kochi in 1974 to explain the stereoselectivity of the reaction. Our investigation reveals how this photocatalytic reaction may be directed along strikingly disparate trajectories by only very minor changes to the structure of the substrate.
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Affiliation(s)
- Gethmini K Jayasekara
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Cali Antolini
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Melissa A Smith
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Danielle J Jacoby
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
| | - Jacqueline Escolastico
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Nathan Girard
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Benjamin T Young
- Department of Physical Sciences, Rhode Island College, 600 Mt Pleasant Avenue, Providence, Rhode Island 02908, United States
| | - Dugan Hayes
- Department of Chemistry, University of Rhode Island, 45 Upper College Road, Kingston, Rhode Island 02881, United States
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Šipr O, Vackář J, Kuzmin A. Effect of atomic vibrations in XANES: polarization-dependent damping of the fine structure at the Cu K-edge of (creat) 2CuCl 4. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:1433-1439. [PMID: 27787249 DOI: 10.1107/s1600577516014570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 09/13/2016] [Indexed: 06/06/2023]
Abstract
Polarization-dependent damping of the fine structure in the Cu K-edge spectrum of creatinium tetrachlorocuprate [(creat)2CuCl4] in the X-ray absorption near-edge structure (XANES) region is shown to be due to atomic vibrations. These vibrations can be separated into two groups, depending on whether the respective atoms belong to the same molecular block; individual molecular blocks can be treated as semi-rigid entities while the mutual positions of these blocks are subject to large mean relative displacements. The effect of vibrations can be efficiently included in XANES calculations by using the same formula as for static systems but with a modified free-electron propagator which accounts for fluctuations in interatomic distances.
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Affiliation(s)
- Ondřej Šipr
- Institute of Physics of the ASCR v.v.i., Cukrovarnicka 10, CZ-162 53 Prague, Czech Republic
| | - Jiří Vackář
- Institute of Physics of the ASCR v.v.i., Na Slovance 2, CZ-182 21 Prague, Czech Republic
| | - Alexei Kuzmin
- Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, LV-1063 Riga, Latvia
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Polarized X-Ray Absorption Spectroscopic Study on Mercuric Bromide Intercalated Bi2Sr2CaCu2Oy Single Crystal. J SOLID STATE CHEM 2001. [DOI: 10.1006/jssc.2000.9180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Ryzhkov MV, Finkelshtein LD, Kurmaev ÉZ, Gubanov VA. Electronic structure and properties of the ground state of copper in semiconducting cuprates. J STRUCT CHEM+ 1995. [DOI: 10.1007/bf02578648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Choy JH, Kim DK, Hwang SH, Demazeau G. Cu K-edge x-ray-absorption spectroscopic study on the octahedrally coordinated trivalent copper in the perovskite-related compounds La2Li0.5Cu0.5O4 and LaCuO3. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 50:16631-16639. [PMID: 9976051 DOI: 10.1103/physrevb.50.16631] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Soldatov AV, Ivanchenko TS, Bianconi A. Two-electron excitations and one-electron multiple-scattering resonances in the x-ray absorption of solid neon. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:16155-16161. [PMID: 10006036 DOI: 10.1103/physrevb.47.16155] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Liang G, Sahiner A, Croft M, Xu W, Xiang X, Badresingh D, Li W, Chen J, Peng J, Zettl A, Lu F. X-ray-absorption near-edge structure study of IBi2Sr2CaCu2Oy. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:1029-1035. [PMID: 10005582 DOI: 10.1103/physrevb.47.1029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Borg A, King PL, Pianetta P, Lindau I, Mitzi DB, Kapitulnik A, Soldatov AV, Bianconi A. Ca 3d unoccupied states in Bi2Sr2CaCu2O8 investigated by Ca L2,3 x-ray-absorption near-edge structure. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:8487-8495. [PMID: 10002613 DOI: 10.1103/physrevb.46.8487] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bianconi A, Li C, Longa SD, Pompa M. Electronic structure of Bi2CaSr2Cu2O8 determined by a combined analysis of various polarized x-ray-absorption spectra. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 45:4989-5000. [PMID: 10002142 DOI: 10.1103/physrevb.45.4989] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bianconi A, Li C, Pompa M, Congiu-Castellano A, Udron D, Flank AM, Lagarde P. Linearly polarized Cu L3-edge x-ray-absorption near-edge structure of Bi2CaSr2Cu2O8. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:10126-10138. [PMID: 9999017 DOI: 10.1103/physrevb.44.10126] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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