1
|
Manoj KM, Gideon DA, Parashar A, Nirusimhan V, Annadurai P, Jacob VD, Manekkathodi A. Validating the predictions of murburn model for oxygenic photosynthesis: Analyses of ligand-binding to protein complexes and cross-system comparisons. J Biomol Struct Dyn 2022; 40:11024-11056. [PMID: 34328391 DOI: 10.1080/07391102.2021.1953607] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this second half of our treatise on oxygenic photosynthesis, we provide support for the murburn model of the light reaction of photosynthesis and ratify key predictions made in the first part. Molecular docking and visualization of various ligands of quinones/quinols (and their derivatives) with PS II/Cytochrome b6f complexes did not support chartered 2e-transport role of quinols. A broad variety of herbicides did not show any affinity/binding-based rationales for inhibition of photosynthesis. We substantiate the proposal that disubstituted phenolics (perceived as protonophores/uncouplers or affinity-based inhibitors in the classical purview) serve as interfacial modulators of diffusible reactive (oxygen) species or DR(O)S. The DRS-based murburn model is evidenced by the identification of multiple ADP-binding sites on the extra-membraneous projection of protein complexes and structure/distribution of the photo/redox catalysts. With a panoramic comparison of the redox metabolic machinery across diverse organellar/cellular systems, we highlight the ubiquitous one-electron murburn facets (cofactors of porphyrin, flavin, FeS, other metal centers and photo/redox active pigments) that enable a facile harnessing of the utility of DRS. In the summative analyses, it is demonstrated that the murburn model of light reaction explains the structures of membrane supercomplexes recently observed in thylakoids and also accounts for several photodynamic experimental observations and evolutionary considerations. In toto, the work provides a new orientation and impetus to photosynthesis research. Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Kelath Murali Manoj
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Daniel Andrew Gideon
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Abhinav Parashar
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Vijay Nirusimhan
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Pushparaj Annadurai
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Vivian David Jacob
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Afsal Manekkathodi
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| |
Collapse
|
2
|
Asfandiarov NL, Galeev RV, Pshenichnyuk SA. Dissociative electron attachment to p-fluoranil and p-chloranil. J Chem Phys 2022; 157:084304. [DOI: 10.1063/5.0102359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The processes of formation and decay of negative molecular ions (NMI) of p-fluoranil (2,3,5,6-tetrafluoro-1,4-benzoquinone, FA) and p-chloranil (2,3,5,6-tetrachloro-1,4-benzoquinone, CA) in the gas phase were investigated. In both cases, long-lived NMIs were found in two resonances, at thermal electron energies and in the region of 0.8-0.9 eV, with lifetimes relative to electron ejection of t a~600 μs. The dissociation of molecular NIs with the formation of fragment ions [M-COF2]ˉ, [M-CO]ˉ and Clˉ proceeds at microsecond times, which is confirmed by the registration of the corresponding metastable ions. It is shown that the dependence of the lifetime of molecular NIs on the electron energy can be explained by the presence of a transition state at an energy of ~0.5 eV.
Collapse
|
3
|
Cinar ME, Lal M, Deiseroth HJ, Schlirf J, Schmittel M. Detection and follow-up reactions of distonic β
, β
-dimesityl enol radical cations containing nitrogen heterocyclic bases. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- M. Emin Cinar
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
| | - Mukul Lal
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
| | | | - Jens Schlirf
- Department Chemie-Biologie; Universität Siegen; Siegen Germany
| | | |
Collapse
|
4
|
Guo C, Wang W, Feng W, Li P. Insights into the one-electron reduction behavior of tetrachloro-o-benzoquinone: a DFT and molecular dynamics study. RSC Adv 2017. [DOI: 10.1039/c7ra00783c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
One-electron reduction behavior of tetrachloro-o-benzoquinone has been studied theoretically and it is a good electron acceptor in various media.
Collapse
Affiliation(s)
- Chao Guo
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
| | - Weihua Wang
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
| | - Wenling Feng
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
| | - Ping Li
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
| |
Collapse
|
5
|
Anstöter CS, West CW, Bull JN, Verlet JRR. The Vitamin E Radical Probed by Anion Photoelectron Imaging. J Phys Chem B 2016; 120:7108-13. [DOI: 10.1021/acs.jpcb.6b05271] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Cate S. Anstöter
- Department
of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | | | - James N. Bull
- Department
of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| | - Jan R. R. Verlet
- Department
of Chemistry, Durham University, Durham DH1 3LE, United Kingdom
| |
Collapse
|
6
|
Kerzig C, Goez M. Combining energy and electron transfer in a supramolecular environment for the "green" generation and utilization of hydrated electrons through photoredox catalysis. Chem Sci 2016; 7:3862-3868. [PMID: 30155030 PMCID: PMC6013799 DOI: 10.1039/c5sc04800a] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/26/2016] [Indexed: 01/08/2023] Open
Abstract
We present a new mechanism that sustainably produces hydrated electrons, i.e., extremely strong reductants, yet consumes only green photons (532 nm) and the bioavailable ascorbate as sacrificial donor. The mechanism couples an energy-transfer cycle, in which a light-harvesting ruthenium polypyridine complex absorbs a first photon and passes the excitation energy on to a pyrene-based redox catalyst, with an electron-transfer cycle, in which the resulting triplet is reductively quenched and the energy-rich aryl radical anion is finally ionized by a second photon. Thus separating the roles of primary and secondary absorber permitted choosing a redox catalyst with a nonabsorbing ground state but efficiently ionizable radical anion; the quantum yield of the ionization step in our complex mechanism surpasses that in a simple photoredox cycle featuring only the metal complex by a factor of four. We suppressed undesired cross reactions through the noncovalent interactions of an anionic micelle with the charges of the reactants, intermediates, and products: the cationic light-harvesting complex remains affixed to the micelle surface, which blocks the access of the negatively charged sacrificial donor, aryl radical anion and hydrated electron, but allows the pyrene ground-state almost unhindered entry into the Stern layer despite a carboxylate substituent by virtue of its large dipole moment. We demonstrate the applicability of the mechanism to the reductive detoxification of halogenated organic waste, which hitherto required UV-C for electron generation, by decomposing the typical model compound chloroacetate.
Collapse
Affiliation(s)
- Christoph Kerzig
- Martin-Luther-Universität Halle-Wittenberg , Institut für Chemie , Kurt-Mothes-Str. 2 , D-06120 Halle (Saale) , Germany .
| | - Martin Goez
- Martin-Luther-Universität Halle-Wittenberg , Institut für Chemie , Kurt-Mothes-Str. 2 , D-06120 Halle (Saale) , Germany .
| |
Collapse
|
7
|
West CW, Bull JN, Woods DA, Verlet JR. Photoelectron imaging as a probe of the repulsive Coulomb barrier in the photodetachment of antimony tartrate dianions. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2015.12.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
8
|
Bull JN, West CW, Verlet JRR. Anion resonances and above-threshold dynamics of coenzyme Q0. Phys Chem Chem Phys 2015; 17:16125-35. [PMID: 26030180 DOI: 10.1039/c5cp02145f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Temporary radical anions (resonances) of isolated co enzyme Q0 (CQ0) and their associated above-threshold dynamics have been studied using frequency-, angle-, and time-resolved photoelectron imaging (FAT-PI). Experimental energetics and dynamics are supported with ab initio calculations. All results support that CQ0 exhibits similar resonances and energetics compared with the smaller para-benzoquinone subunit, which is commonly considered as a prototype electrophore for larger biological para-quinone species. However, the above-threshold dynamics in CQ0 relative to para-benzoquinone show significantly enhanced prompt detachment compared with internal conversion, particularly around the photoexcitation energy of 3.10 eV. The change in dynamics can be attributed to a combination of an increase in the shape character of the optically-accessible resonance at this energy, a decrease in the autodetachment lifetime due to the higher density of states in the neutral, and a decrease in the probability that the wavepacket formed in the Franck-Condon window can access the local conical intersection in CQ0 over the timescale of autodetachment. Overall, this study serves as a clear example in understanding the trends in spectroscopy and dynamics in relating a simple prototypical para-quinone electrophore to a more complex biochemical species.
Collapse
Affiliation(s)
- James N Bull
- Department of Chemistry, Durham University, South Road, DH1 3LE, UK.
| | | | | |
Collapse
|
9
|
Bull JN, West CW, Verlet JRR. On the formation of anions: frequency-, angle-, and time-resolved photoelectron imaging of the menadione radical anion. Chem Sci 2015; 6:1578-1589. [PMID: 29560245 PMCID: PMC5811081 DOI: 10.1039/c4sc03491k] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 12/17/2014] [Indexed: 11/24/2022] Open
Abstract
Frequency-, angle-, and time-resolved photoelectron imaging of gas-phase menadione (vitamin K3) radical anions was used to show that quasi-bound resonances of the anion can act as efficient doorway states to produce metastable ground electronic state anions on a sub-picosecond timescale. Several anion resonances have been experimentally observed and identified with the assistance of ab initio calculations, and ground state anion recovery was observed across the first 3 eV above threshold. Time-resolved measurements revealed the mechanism of electronic ground state anion formation, which first involves a cascade of very fast internal conversion processes to a bound electronic state that, in turn, decays by slower internal conversion to the ground state. Autodetachment processes from populated resonances are inefficient compared with electronic relaxation through internal conversion. The mechanistic understanding gained provides insight into the formation of radical anions in biological and astrochemical systems.
Collapse
Affiliation(s)
- James N Bull
- Department of Chemistry , Durham University , South Road , DH1 3LE , UK .
| | - Christopher W West
- Department of Chemistry , Durham University , South Road , DH1 3LE , UK .
| | - Jan R R Verlet
- Department of Chemistry , Durham University , South Road , DH1 3LE , UK .
| |
Collapse
|
10
|
Horke DA, Chatterley AS, Bull JN, Verlet JRR. Time-Resolved Photodetachment Anisotropy: Gas-Phase Rotational and Vibrational Dynamics of the Fluorescein Anion. J Phys Chem Lett 2015; 6:189-94. [PMID: 26263111 DOI: 10.1021/jz5022526] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The photoelectron signal of the singly deprotonated fluorescein anion is found to be highly dependent on the relative polarization between pump and probe pulses, and time-resolved photodetachment anisotropy (TR-PA) is developed as a probe of the rotational dynamics of the chromophore. The total photoelectron signal shows both rotational and vibrational wavepacket dynamics, and we demonstrate how TR-PA can readily disentangle these dynamical processes. TR-PA in fluorescein presents specific opportunities for its development as a probe for rotational dynamics in large biomolecules as fluorescein derivatives are commonly incorporated in complex biomolecules and have been used extensively in time-resolved fluorescence anisotropy measurements, to which TR-PA is a gas-phase analogue.
Collapse
Affiliation(s)
- Daniel A Horke
- †Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Adam S Chatterley
- ‡Ultrafast X-ray Science Laboratory, Cyclotron Road, Berkeley, California 94720, United States
| | - James N Bull
- §Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, United Kingdom
| | - Jan R R Verlet
- §Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, United Kingdom
| |
Collapse
|
11
|
West CW, Bull JN, Antonkov E, Verlet JRR. Anion resonances of para-benzoquinone probed by frequency-resolved photoelectron imaging. J Phys Chem A 2014; 118:11346-54. [PMID: 25301059 DOI: 10.1021/jp509102p] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The resonant attachment of a free electron to a closed shell neutral molecule and the interplay between the following electron detachment and electronic relaxation channels represents a fundamental but common process throughout chemical and biochemical systems. The new methodology of anion frequency-resolved photoelectron imaging is detailed and used to map out molecular excited state dynamics of gas-phase para-benzoquinone, which is the electron accepting moiety in many biological electron-transfer chains. Three-dimensional spectra of excitation energy, electron kinetic energy, and electron ejection anisotropy reveal clear fingerprints of excited and intermediate state dynamics. The results show that many of the excited states are strongly coupled, providing a route to forming the ground state radical anion, despite the fact that the electron is formally unbound in the excited states. The relation of our method to electron impact attachment studies and the key advantages, including the extension to time-resolved dynamics and to larger molecular systems, are discussed.
Collapse
Affiliation(s)
- Christopher W West
- Department of Chemistry, Durham University , Durham, DH1 3LE, United Kingdom
| | | | | | | |
Collapse
|
12
|
Chatterley AS, West CW, Roberts GM, Stavros VG, Verlet JRR. Mapping the Ultrafast Dynamics of Adenine onto Its Nucleotide and Oligonucleotides by Time-Resolved Photoelectron Imaging. J Phys Chem Lett 2014; 5:843-848. [PMID: 26274076 DOI: 10.1021/jz500264c] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The intrinsic photophysics of nucleobases and nucleotides following UV absorption presents a key reductionist step toward understanding the complex photodamage mechanisms occurring in DNA. The decay mechanism of adenine in particular has been the focus of intense investigation, as has how these correlate to those of its more biologically relevant nucleotide and oligonucleotides in aqueous solution. Here, we report on time-resolved photoelectron imaging of the deprotonated 3'-deoxy-adenosine-5'-monophosphate nucleotide and the adenosine di- and trinucleotides. Through a comparison of gas- and solution-phase experiments and available theoretical studies, the dynamics of the base are shown to be relatively insensitive to the surrounding environment. The decay mechanism primarily involves internal conversion from the initially populated (1)ππ* states to the ground state. The relaxation dynamics of the adenosine oligonucleotides are similar to those of the nucleobase, in contrast to the aqueous oligonucleotides, where a fraction of the ensemble forms long-lived excimer states.
Collapse
Affiliation(s)
- Adam S Chatterley
- †Department of Chemistry, University of Durham, Durham DH1 3LE, United Kingdom
- ‡Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Christopher W West
- †Department of Chemistry, University of Durham, Durham DH1 3LE, United Kingdom
| | - Gareth M Roberts
- ‡Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Vasilios G Stavros
- ‡Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Jan R R Verlet
- †Department of Chemistry, University of Durham, Durham DH1 3LE, United Kingdom
| |
Collapse
|
13
|
Chatterley AS, West CW, Stavros VG, Verlet JRR. Time-resolved photoelectron imaging of the isolated deprotonated nucleotides. Chem Sci 2014. [DOI: 10.1039/c4sc01493f] [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
Time-resolved photoelectron spectroscopy of deprotonated nucleotides provides new insights into their relaxation dynamics.
Collapse
Affiliation(s)
- Adam S. Chatterley
- Department
- of Chemistry
- University of Durham
- Durham DH1 3LE, United Kingdom
- Department of Chemistry
| | | | - Vasilios G. Stavros
- Department of Chemistry
- University of Warwick
- Coventry CV4 7AL, United Kingdom
| | - Jan R. R. Verlet
- Department
- of Chemistry
- University of Durham
- Durham DH1 3LE, United Kingdom
| |
Collapse
|
14
|
Verlet JRR, Horke DA, Chatterley AS. Excited states of multiply-charged anions probed by photoelectron imaging: riding the repulsive Coulomb barrier. Phys Chem Chem Phys 2014; 16:15043-52. [DOI: 10.1039/c4cp01667j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent progress towards understanding the repulsive Coulomb barrier in multiply-charged anion using photoelectron spectroscopy is discussed.
Collapse
Affiliation(s)
| | - Daniel A. Horke
- Center for Free-Electron Laser Science
- DESY
- 22607 Hamburg, Germany
| | | |
Collapse
|
15
|
Chatterley AS, Horke DA, Verlet JRR. Effects of resonant excitation, pulse duration and intensity on photoelectron imaging of a dianion. Phys Chem Chem Phys 2014; 16:489-96. [DOI: 10.1039/c3cp53235f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
16
|
Horke DA, Chatterley AS, Verlet JRR. Influence of the repulsive Coulomb barrier on photoelectron spectra and angular distributions in a resonantly excited dianion. J Chem Phys 2013; 139:084302. [DOI: 10.1063/1.4818597] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
|
17
|
West CW, Hudson AS, Cobb SL, Verlet JRR. Communication: Autodetachment versus internal conversion from the S1 state of the isolated GFP chromophore anion. J Chem Phys 2013; 139:071104. [DOI: 10.1063/1.4819078] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
|
18
|
Li P, Wang W, Sun Q, Li Z, Du A, Bi S, Zhao Y. Insights into the Mechanism of the Reaction between Tetrachloro‐
p‐
Benzoquinone and Hydrogen Peroxide and their Implications in the Catalytic Role of Water Molecules in Producing the Hydroxyl Radial. Chemphyschem 2013; 14:2737-43. [PMID: 23893963 DOI: 10.1002/cphc.201300395] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 05/07/2013] [Indexed: 11/06/2022]
Affiliation(s)
- Ping Li
- Key Laboratory of Life‐Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, 273165 (P. R. China)
| | - Weihua Wang
- Key Laboratory of Life‐Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, 273165 (P. R. China)
| | - Qiao Sun
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, QLD 4072 (Australia)
| | - Zhen Li
- Institute of Superconducting and Electronic Materials, University of Wollongong, NSW 2500 (Australia)
| | - Aijun Du
- School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4001 (Australia)
| | - Siwei Bi
- Key Laboratory of Life‐Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, 273165 (P. R. China)
| | - Yan Zhao
- Key Laboratory of Life‐Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, 273165 (P. R. China)
| |
Collapse
|
19
|
Horke DA, Li Q, Blancafort L, Verlet JRR. Ultrafast above-threshold dynamics of the radical anion of a prototypical quinone electron-acceptor. Nat Chem 2013; 5:711-7. [PMID: 23881504 DOI: 10.1038/nchem.1705] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 06/04/2013] [Indexed: 12/30/2022]
Abstract
Quinones feature prominently as electron acceptors in nature. Their electron-transfer reactions are often highly exergonic, for which Marcus theory predicts reduced electron-transfer rates because of a free-energy barrier that occurs in the inverted region. However, the electron-transfer kinetics that involve quinones can appear barrierless. Here, we consider the intrinsic properties of the para-benzoquinone radical anion, which serves as the prototypical electron-transfer reaction product involving a quinone-based acceptor. Using time-resolved photoelectron spectroscopy and ab initio calculations, we show that excitation at 400 and 480 nm yields excited states that are unbound with respect to electron loss. These excited states are shown to decay on a sub-40 fs timescale through a series of conical intersections with lower-lying excited states, ultimately to form the ground anionic state and avoid autodetachment. From an isolated electron-acceptor perspective, this ultrafast stabilization mechanism accounts for the ability of para-benzoquinone to capture and retain electrons.
Collapse
Affiliation(s)
- Daniel A Horke
- Department of Chemistry, University of Durham, Durham DH1 3LE, UK
| | | | | | | |
Collapse
|
20
|
Chatterley AS, Johns AS, Stavros VG, Verlet JRR. Base-specific ionization of deprotonated nucleotides by resonance enhanced two-photon detachment. J Phys Chem A 2013; 117:5299-305. [PMID: 23642262 DOI: 10.1021/jp4041315] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The intrinsic ionization energy of a base in DNA plays a critical role in determining the energies at which damage mechanisms may emerge. Here, a two-photon resonance-enhanced ionization scheme is presented that utilizes the (1)ππ* transition, localized on the DNA base, to elucidate the base-specific ionization in a deprotonated nucleotide. In contrast to previous reports, the scheme is insensitive to competing ionization channels arising from the sugar-phosphate backbone. Using this approach, we demonstrate that for all bases except guanine, the lowest electron detachment energy corresponds to detachment from the sugar-phosphate backbone and allows us to determine the lowest adiabatic ionization energy for the other three bases for the first time in an isolated nucleotide.
Collapse
Affiliation(s)
- Adam S Chatterley
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | | | | | | |
Collapse
|
21
|
Li P, Wang WH, Sun HT, Bi SW. A DFT study on the electron affinity of tetrachloro-p-benzoquinone: Toward to understanding its electron-accepting ability in solution. COMPUT THEOR CHEM 2013. [DOI: 10.1016/j.comptc.2012.11.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
22
|
Ómarsson B, Ingólfsson O. Stabilization, fragmentation and rearrangement reactions in low-energy electron interaction with tetrafluoro-para-benzoquinone: a combined theoretical and experimental study. Phys Chem Chem Phys 2013; 15:16758-67. [DOI: 10.1039/c3cp52397g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
23
|
Abstract
In this chapter, most of the reported work deals with the photochemistry of carbonyl compounds; however, the photoreactions of other functions, such as the photo-Claisen rearrangement or the photocleavage of cyclic ethers, are also included. In the present volume, time coverage is 2010–2011, and only original research articles are quoted. In general, reviews or purely theoretical calculations are not systematically included. As usually, the material is organized according to established types of reactions (e.g., Norrish I/II, hydrogen abstraction, Paternò-Büchi, photoelimination, photo-Fries/photo-Claisen, etc.). After presenting the basic photochemical aspects, more specific findings are reported. They include synthetic applications, stereoselectivity, and biological or technological implications. Next, the attention is focused on photochemical reactions in anisotropic media, including (micro)heterogeneous or supramolecular systems, solid matrixes or fully organized crystals. Finally, mechanistic studies based on direct experimental evidence are highlighted, especially when transient absorption spectroscopy or related ultrafast detection are employed.
Collapse
Affiliation(s)
- M. Consuelo Jiménez
- Departamento de Química, Instituto de Tecnología Química UPV-CSIC Universidad Politécnica de Valencia camino de Vera s/n, E-46022 Valencia Spain
| | - Miguel A. Miranda
- Departamento de Química, Instituto de Tecnología Química UPV-CSIC Universidad Politécnica de Valencia camino de Vera s/n, E-46022 Valencia Spain
| |
Collapse
|
24
|
Theoretical studies on the interaction mechanisms between tetrachloro-p-benzoquinone and hydrogen peroxide. Struct Chem 2012. [DOI: 10.1007/s11224-012-0155-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
25
|
Grilj J, Buchgraber P, Vauthey E. Excited-State Dynamics of Wurster’s Salts. J Phys Chem A 2012; 116:7516-22. [DOI: 10.1021/jp3045548] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Jakob Grilj
- Department
of Physical Chemistry and ‡Department of Organic Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211
Geneva 4
| | - Philipp Buchgraber
- Department
of Physical Chemistry and ‡Department of Organic Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211
Geneva 4
| | - Eric Vauthey
- Department
of Physical Chemistry and ‡Department of Organic Chemistry, University of Geneva, 30 quai Ernest-Ansermet, CH-1211
Geneva 4
| |
Collapse
|
26
|
Horke DA, Roberts GM, Lecointre J, Verlet JRR. Velocity-map imaging at low extraction fields. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:063101. [PMID: 22755609 DOI: 10.1063/1.4724311] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present a velocity-map imaging (VMI) setup for photoelectron imaging that utilizes low electric extraction fields. This avoids any complications that could arise from electrostatic interactions between the extraction field and the molecular properties that are probed and has a minimal effect on the trajectory of ions in ion beam experiments. By using an attractive potential supplied to the detector, and keeping the electrodes at ground (zero) potential, we show that fringe fields between the VMI arrangement and the vacuum chamber can be eliminated, which is important in experiments on ions.
Collapse
Affiliation(s)
- Daniel A Horke
- Department of Chemistry, University of Durham, South Road, DH1 3LE Durham, United Kingdom
| | | | | | | |
Collapse
|
27
|
Horke DA, Chatterley AS, Verlet JRR. Femtosecond Photoelectron Imaging of Aligned Polyanions: Probing Molecular Dynamics through the Electron-Anion Coulomb Repulsion. J Phys Chem Lett 2012; 3:834-8. [PMID: 26286406 DOI: 10.1021/jz3000933] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The first time-resolved photoelectron imaging study of a polyanion is presented. Using the alignment induced through resonance excitation, the photoelectron angular distributions can be qualitatively understood in terms of the position of localized excess charges on the molecular skeleton, which influence the photoemission dynamics. Pump-probe experiments are used to demonstrate that the photoelectron angular distribution is also sensitive to molecular dynamics. This is shown here for the rotational dynamics of a polyanion, in which the photoelectron anisotropy tracks the rotational coherence as it dephases. The methodology can in principle be applied to general molecular dynamics in large polyanions, providing a new route to studying ultrafast structural dynamics in complex gas-phase systems.
Collapse
Affiliation(s)
- Daniel A Horke
- Department of Chemistry, University of Durham, DH1 3LE Durham, United Kingdom
| | - Adam S Chatterley
- Department of Chemistry, University of Durham, DH1 3LE Durham, United Kingdom
| | - Jan R R Verlet
- Department of Chemistry, University of Durham, DH1 3LE Durham, United Kingdom
| |
Collapse
|
28
|
Horke DA, Chatterley AS, Verlet JRR. Effect of internal energy on the repulsive Coulomb barrier of polyanions. PHYSICAL REVIEW LETTERS 2012; 108:083003. [PMID: 22463527 DOI: 10.1103/physrevlett.108.083003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Indexed: 05/28/2023]
Abstract
The nature of the repulsive Coulomb barrier in isolated molecular polyanions is studied by means of the photodetachment dynamics of the S(1) excited state of the fluorescein dianion which is bound solely by the repulsive Coulomb barrier. Photoelectron spectra reveal a feature at a constant electron kinetic energy, regardless of the excitation energy. This is explained by using an adiabatic tunneling picture for electron loss through successive repulsive Coulomb barriers correlating to vibrationally excited states. This physical picture is supported by time-resolved photoelectron spectra, showing that the tunneling lifetime is also invariant with excitation energy.
Collapse
Affiliation(s)
- Daniel A Horke
- Department of Chemistry, University of Durham, Durham, United Kingdom
| | | | | |
Collapse
|
29
|
Horke DA, Verlet JRR. Photoelectron spectroscopy of the model GFP chromophore anion. Phys Chem Chem Phys 2012; 14:8511-5. [DOI: 10.1039/c2cp40880e] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|