1
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López-Martín I, Veiga-Herrero J, Aparicio F, González-Rodríguez D. A Modular and Convergent Synthetic Route to Supramolecular Cyclic Dimers Based on Amidinium-Carboxylate Interactions. Chemistry 2023; 29:e202302279. [PMID: 37800622 DOI: 10.1002/chem.202302279] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Indexed: 10/07/2023]
Abstract
We describe herein the optimized design and modular synthetic approach towards supramolecularly programmed monomers that can form discrete macrocyclic species of controllable size and shape through amidinium-carboxylate interactions in apolar and polar media.
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Affiliation(s)
- Isabel López-Martín
- Nanostructured Molecular Systems and Materials Group, Organic Chemistry Department, Science Faculty, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Jacobo Veiga-Herrero
- Nanostructured Molecular Systems and Materials Group, Organic Chemistry Department, Science Faculty, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Fátima Aparicio
- Nanostructured Molecular Systems and Materials Group, Organic Chemistry Department, Science Faculty, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - David González-Rodríguez
- Nanostructured Molecular Systems and Materials Group, Organic Chemistry Department, Science Faculty, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049, Madrid, Spain
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2
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Wang C, O'Hagan MP, Willner B, Willner I. Bioinspired Artificial Photosynthetic Systems. Chemistry 2021; 28:e202103595. [PMID: 34854505 DOI: 10.1002/chem.202103595] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Indexed: 12/18/2022]
Abstract
Mimicking photosynthesis using artificial systems, as a means for solar energy conversion and green fuel generation, is one of the holy grails of modern science. This perspective presents recent advances towards developing artificial photosynthetic systems. In one approach, native photosystems are interfaced with electrodes to yield photobioelectrochemical cells that transform light energy into electrical power. This is exemplified by interfacing photosystem I (PSI) and photosystem II (PSII) as an electrically contacted assembly mimicking the native Z-scheme, and by the assembly of an electrically wired PSI/glucose oxidase biocatalytic conjugate on an electrode support. Illumination of the functionalized electrodes led to light-induced generation of electrical power, or to the generation of photocurrents using glucose as the fuel. The second approach introduces supramolecular photosensitizer nucleic acid/electron acceptor complexes as functional modules for effective photoinduced electron transfer stimulating the subsequent biocatalyzed generation of NADPH or the Pt-nanoparticle-catalyzed evolution of molecular hydrogen. Application of the DNA machineries for scaling-up the photosystems is demonstrated. A third approach presents the integration of artificial photosynthetic modules into dynamic nucleic acid networks undergoing reversible reconfiguration or dissipative transient operation in the presence of auxiliary triggers. Control over photoinduced electron transfer reactions and photosynthetic transformations by means of the dynamic networks is demonstrated.
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Affiliation(s)
- Chen Wang
- Institute of Chemistry, The Minerva Centre for Bio-Hybrid Complex Systems, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Michael P O'Hagan
- Institute of Chemistry, The Minerva Centre for Bio-Hybrid Complex Systems, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Bilha Willner
- Institute of Chemistry, The Minerva Centre for Bio-Hybrid Complex Systems, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Itamar Willner
- Institute of Chemistry, The Minerva Centre for Bio-Hybrid Complex Systems, The Hebrew University of Jerusalem, Jerusalem, Israel
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3
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Tyburski R, Liu T, Glover SD, Hammarström L. Proton-Coupled Electron Transfer Guidelines, Fair and Square. J Am Chem Soc 2021; 143:560-576. [PMID: 33405896 PMCID: PMC7880575 DOI: 10.1021/jacs.0c09106] [Citation(s) in RCA: 196] [Impact Index Per Article: 65.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Indexed: 12/23/2022]
Abstract
Proton-coupled electron transfer (PCET) reactions are fundamental to energy transformation reactions in natural and artificial systems and are increasingly recognized in areas such as catalysis and synthetic chemistry. The interdependence of proton and electron transfer brings a mechanistic richness of reactivity, including various sequential and concerted mechanisms. Delineating between different PCET mechanisms and understanding why a particular mechanism dominates are crucial for the design and optimization of reactions that use PCET. This Perspective provides practical guidelines for how to discern between sequential and concerted mechanisms based on interpretations of thermodynamic data with temperature-, pressure-, and isotope-dependent kinetics. We present new PCET-zone diagrams that show how a mechanism can switch or even be eliminated by varying the thermodynamic (ΔGPT° and ΔGET°) and coupling strengths for a PCET system. We discuss the appropriateness of asynchronous concerted PCET to rationalize observations in organic reactions, and the distinction between hydrogen atom transfer and other concerted PCET reactions. Contemporary issues and future prospects in PCET research are discussed.
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Affiliation(s)
- Robin Tyburski
- Ångström
Laboratory, Department of Chemistry, Uppsala
University, Box 523, SE75120 Uppsala, Sweden
| | - Tianfei Liu
- Department
of Chemistry, University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599-3290, United States
| | - Starla D. Glover
- Ångström
Laboratory, Department of Chemistry, Uppsala
University, Box 523, SE75120 Uppsala, Sweden
| | - Leif Hammarström
- Ångström
Laboratory, Department of Chemistry, Uppsala
University, Box 523, SE75120 Uppsala, Sweden
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4
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Bouakil M, Chirot F, Girod M, Dugourd P, MacAleese L. Secondary structure effects on internal proton transfer in poly-peptides. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:024302. [PMID: 32232075 PMCID: PMC7100371 DOI: 10.1063/4.0000003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 02/21/2020] [Indexed: 12/21/2022]
Abstract
A pump-probe approach was designed to determine the internal proton transfer (PT) rate in a series of poly-peptide radical cations containing both histidine and tryptophan. The proton transfer is driven by the gas-phase basicity difference between residues. The fragmentation scheme indicates that the gas-phase basicity of histidine is lower than that of radical tryptophan so that histidine is always pulling the proton away from tryptophan. However, the proton transfer requires the two basic sites to be in close proximity, which is rate limited by the peptide conformational dynamics. PT rate measurements were used to probe and explore the peptide conformational dynamics in several poly-glycines/prolines/alanines. For small and unstructured peptides, the PT rate decreases with the size, as expected from a statistical point of view in a flat conformational space. Conversely, if structured conformations are accessible, the structural flexibility of the peptide is decreased. This slows down the occurrence of conformations favorable to proton transfer. A dramatic decrease in the PT rates was observed for peptides HAnW, when n changes from 5 to 6. This is attributed to the onset of a stable helix for n = 6. No such discontinuity is observed for poly-glycines or poly-prolines. In HAnW, the gas-phase basicity and helix propensity compete for the position of the charge. Interestingly, in this competition between PT and helix formation in HA6W, the energy gain associated with helix formation is large enough to slow down the PT beyond experimental time but does not ultimately prevail over the proton preference for histidine.
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Affiliation(s)
- M Bouakil
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Lyon, France
| | - F Chirot
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut des Sciences Analytiques, F-69622 Lyon, France
| | - M Girod
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut des Sciences Analytiques, F-69622 Lyon, France
| | - P Dugourd
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Lyon, France
| | - L MacAleese
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Lyon, France
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5
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Liu T, Tyburski R, Wang S, Fernández-Terán R, Ott S, Hammarström L. Elucidating Proton-Coupled Electron Transfer Mechanisms of Metal Hydrides with Free Energy- and Pressure-Dependent Kinetics. J Am Chem Soc 2019; 141:17245-17259. [PMID: 31587555 DOI: 10.1021/jacs.9b08189] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Proton-coupled electron transfer (PCET) was studied in a series of tungsten hydride complexes with pendant pyridyl arms ([(PyCH2Cp)WH(CO)3], PyCH2Cp = pyridylmethylcyclopentadienyl), triggered by laser flash-generated RuIII-tris-bipyridine oxidants, in acetonitrile solution. The free energy dependence of the rate constant and the kinetic isotope effects (KIEs) showed that the PCET mechanism could be switched between concerted and the two stepwise PCET mechanisms (electron-first or proton-first) in a predictable fashion. Straightforward and general guidelines for how the relative rates of the different mechanisms depend on oxidant and base are presented. The rate of the concerted reaction should depend symmetrically on changes in oxidant and base strength, that is on the overall ΔG0PCET, and we argue that an "asynchronous" behavior would not be consistent with a model where the electron and proton tunnel from a common transition state. The observed rate constants and KIEs were examined as a function of hydrostatic pressure (1-2000 bar) and were found to exhibit qualitatively different dependence on pressure for different PCET mechanisms. This is discussed in terms of different volume profiles of the PCET mechanisms as well as enhanced proton tunneling for the concerted mechanism. The results allowed for assignment of the main mechanism operating in the different cases, which is one of the critical questions in PCET research. They also show how the rate of a PCET reaction will be affected very differently by changes of oxidant and base strength, depending on which mechanism dominates. This is of fundamental interest as well as of practical importance for rational design of, for example, catalysts for fuel cells and solar fuel formation, which operate in steps of PCET reactions. The mechanistic richness shown by this system illustrates that the specific mechanism is not intrinsic to a specific synthetic catalyst or enzyme active site but depends on the reaction conditions.
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Affiliation(s)
- Tianfei Liu
- Department of Chemistry, Ångström Laboratory , Uppsala University , Box 532, SE-751 20 Uppsala , Sweden
| | - Robin Tyburski
- Department of Chemistry, Ångström Laboratory , Uppsala University , Box 532, SE-751 20 Uppsala , Sweden
| | - Shihuai Wang
- Department of Chemistry, Ångström Laboratory , Uppsala University , Box 532, SE-751 20 Uppsala , Sweden
| | - Ricardo Fernández-Terán
- Department of Chemistry, Ångström Laboratory , Uppsala University , Box 532, SE-751 20 Uppsala , Sweden
| | - Sascha Ott
- Department of Chemistry, Ångström Laboratory , Uppsala University , Box 532, SE-751 20 Uppsala , Sweden
| | - Leif Hammarström
- Department of Chemistry, Ångström Laboratory , Uppsala University , Box 532, SE-751 20 Uppsala , Sweden
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6
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Küçüköz B, Adinarayana B, Osuka A, Albinsson B. Electron transfer reactions in sub-porphyrin-naphthyldiimide dyads. Phys Chem Chem Phys 2019; 21:16477-16485. [PMID: 31321401 DOI: 10.1039/c9cp03725j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A series of donor-acceptor compounds based on a sub-porphyrin (SubP) as an electron donor and naphthyldiimide (NDI) as an acceptor has been designed, synthesized and investigated by time-resolved emission and transient absorption measurements. The donor and acceptor are separated by a single phenyl spacer substituted by methyl groups in order to systematically vary the electronic coupling. The electron transfer reactions in toluene are found to be quite fast; charge separation is quantitative and occurs within 5-10 ps and charge recombination occurs in 1-10 ns, depending on the substitution pattern. As expected, when steric bulk is introduced on the adjoining phenyl group, electron transfer rates slow down because of smaller electronic coupling. Quantum mechanical modelling of the potential energy for twisting the dihedral angles combined with a simplified model of the electronic coupling semi-quantitatively explains the observed variation of the electron transfer rates. Investigating the temperature variation of the charge separation in 2-methyltetrahydrofuran (2-MTHF) and analyzing using the Marcus model allow experimental estimation of the electronic coupling and reorganization energies. At low temperature, relatively strong phosphorescence is observed from the donor-acceptor compounds with onset at 660 nm signaling that charge recombination occurs, at least partially, through the sub-porphyrin localized triplet excited state. Finally, it is noted that charge separation in all SubP-NDI dyads is efficient even at cryogenic temperatures (85 K) in 2-MTHF glass.
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Affiliation(s)
- Betül Küçüköz
- Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
| | - B Adinarayana
- Department of Chemistry, Kyoto University, Kyoto, Japan
| | | | - Bo Albinsson
- Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden.
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7
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Ghosh R, Mora AK, Nath S. Disentangling Time Scales of Vibrational Cooling, Solvation, and Hydrogen Bond Reorganization Dynamics Using Ultrafast Transient Infrared Spectroscopy of Formylperylene. J Phys Chem B 2019; 123:4408-4414. [DOI: 10.1021/acs.jpcb.9b01920] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Rajib Ghosh
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Aruna K. Mora
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Sukhendu Nath
- Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
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8
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Drolen C, Conklin E, Hetterich SJ, Krishnamurthy A, Andrade GA, Dimeglio JL, Martin MI, Tran LK, Yap GPA, Rosenthal J, Young ER. pH-Driven Mechanistic Switching from Electron Transfer to Energy Transfer between [Ru(bpy) 3] 2+ and Ferrocene Derivatives. J Am Chem Soc 2018; 140:10169-10178. [PMID: 30070469 PMCID: PMC6192533 DOI: 10.1021/jacs.8b03933] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The metal-to-ligand charge transfer excited states of [Ru(bpy)3]2+ (bpy = 2,2'-bipyridine) may be deactivated via energy transfer or electron transfer with ferrocene derivatives in aqueous conditions. Stern-Volmer quenching analysis revealed that the rate constant for [Ru(bpy)3]2+ excited-state quenching depends on solution pH when a ferrocenyl-amidinium derivative (Fc-am) containing a proton-responsive functionality tethered to the ferrocene center was present. By contrast, the rate constant with which the [Ru(bpy)3]2+ excited state is quenched by an analogous ferrocene derivative (ferrocenyl-trimethylammonium, Fc-mam) that lacks a protonic group does not depend on pH. These results show that the presence (or absence) of a readily transferrable proton modulates quenching rate constants in bimolecular events involving [Ru(bpy)3]2+ and ferrocene. More surprisingly, transient absorption spectroscopy reveals that the mechanism by which the [Ru(bpy)3]2+ excited state is quenched by Fc-am appears to be modulated by solution proton availability, switching from energy transfer at low pH when Fc-am is protonated, to electron transfer at high pH when Fc-am is deprotonated. The mechanistic switching that is observed for this system cannot be aptly explained using a simple driving force dependence argument, suggesting that more subtle factors dictate the pathway by which the [Ru(bpy)3]2+ excited state is deactivated by ferrocene in aqueous solutions.
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Affiliation(s)
- Claire Drolen
- Department of Chemistry, Amherst College, Merrill Science Building, Amherst, Massachusetts 01002, United States
| | - Eric Conklin
- Department of Chemistry, Amherst College, Merrill Science Building, Amherst, Massachusetts 01002, United States
| | - Stephen J. Hetterich
- Department of Chemistry, Amherst College, Merrill Science Building, Amherst, Massachusetts 01002, United States
| | - Aditi Krishnamurthy
- Department of Chemistry, Amherst College, Merrill Science Building, Amherst, Massachusetts 01002, United States
| | - Gabriel A. Andrade
- Department of Chemistry and Biochemistry, Brown Laboratory, University of Delaware, Newark, Delaware 19716, United States
| | - John L. Dimeglio
- Department of Chemistry and Biochemistry, Brown Laboratory, University of Delaware, Newark, Delaware 19716, United States
| | - Maxwell I. Martin
- Department of Chemistry and Biochemistry, Brown Laboratory, University of Delaware, Newark, Delaware 19716, United States
| | - Linh K. Tran
- Department of Chemistry and Biochemistry, Brown Laboratory, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P. A. Yap
- Department of Chemistry and Biochemistry, Brown Laboratory, University of Delaware, Newark, Delaware 19716, United States
| | - Joel Rosenthal
- Department of Chemistry and Biochemistry, Brown Laboratory, University of Delaware, Newark, Delaware 19716, United States
| | - Elizabeth R. Young
- Department of Chemistry, Amherst College, Merrill Science Building, Amherst, Massachusetts 01002, United States
- Department of Chemistry, Lehigh University, Seeley G. Mudd Building, Bethlehem, Pennsylvania, 18015, United States
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9
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Mandal A, Shakib FA, Huo P. Investigating photoinduced proton coupled electron transfer reaction using quasi diabatic dynamics propagation. J Chem Phys 2018; 148:244102. [DOI: 10.1063/1.5030634] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Arkajit Mandal
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14627, USA
| | - Farnaz A. Shakib
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14627, USA
| | - Pengfei Huo
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14627, USA
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10
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Hossen T, Sahu K. New Insights on Hydrogen-Bond-Induced Fluorescence Quenching Mechanism of C102-Phenol Complex via Proton Coupled Electron Transfer. J Phys Chem A 2018; 122:2394-2400. [PMID: 29455531 DOI: 10.1021/acs.jpca.7b12055] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The H-bonded coumarin 102 (C102)-phenol complex has been a model system usually used to understand the influence of H-bonding on photophysical processes. Zhao and Han first showed that significant H-bond strengthening occurs in the excited state and proposed the possibility of fluorescence quenching in the complex via internal conversion from a locally excited (LE) state to a low-lying charge transfer (CT) state. Later, we experimentally confirmed fluorescence quenching of C102-phenol complex in a nonpolar solvent (cyclohexane). However, we also found that the existence of the low-lying CT state is ambiguous. Here, we proposed an alternative mechanism for the fluorescence quenching in the H-bonded complex. For this, we evaluate the excited state potential energy surface considering complete H atom-transfer from phenol to C102 along the H-bonding coordinate. Surprisingly, we observed two distinct minima separated by a low-energy barrier. One minimum corresponds to the complex with shortening of H-bond consistent with that of Zhao and Han. On the other hand, the second minimum, which has even lower energy than the first minimum, is likely to be arising from the proton-coupled electron transfer (PCET) process. The nature of the lowest excited state alters from LE to CT type at the second minimum, which may account for the fluorescence quenching phenomena in the system.
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Affiliation(s)
- Tousif Hossen
- Department of Chemistry , Indian Institute of Technology Guwahati , Guwahati 781039 , Assam India
| | - Kalyanasis Sahu
- Department of Chemistry , Indian Institute of Technology Guwahati , Guwahati 781039 , Assam India
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11
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Dey A, Dana J, Aute S, Maity P, Das A, Ghosh HN. Proton-Coupled Electron-Transfer Processes in Ultrafast Time Domain: Evidence for Effects of Hydrogen-Bond Stabilization on Photoinduced Electron Transfer. Chemistry 2017; 23:3455-3465. [DOI: 10.1002/chem.201605594] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Ananta Dey
- Organic Chemistry Division CSIR; National Chemical Laboratory; Pune, Maharashtra 411008 India
| | - Jayanta Dana
- Radiation and Photochemistry Division; Bhabha Atomic Research Centre; Mumbai 400085 India
| | - Sunil Aute
- Organic Chemistry Division CSIR; National Chemical Laboratory; Pune, Maharashtra 411008 India
| | - Partha Maity
- Radiation and Photochemistry Division; Bhabha Atomic Research Centre; Mumbai 400085 India
| | - Amitava Das
- Organic Chemistry Division CSIR; National Chemical Laboratory; Pune, Maharashtra 411008 India
- CSIR-Central Salt and Marine Chemicals Research Institute; Bhavnagar 364002 Gujarat India
| | - Hirendra N. Ghosh
- Radiation and Photochemistry Division; Bhabha Atomic Research Centre; Mumbai 400085 India
- Institute of Nano Science and Technology; Mohali Punjab 160062 India
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12
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Ghosh R, Mora AK, Nath S, Palit DK. Ultrafast Dynamics of Hydrogen Bond Breaking and Making in the Excited State of Fluoren-9-one: Time-Resolved Visible Pump–IR Probe Spectroscopic Study. J Phys Chem B 2017; 121:1068-1080. [DOI: 10.1021/acs.jpcb.6b11293] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rajib Ghosh
- Radiation and Photochemistry
Division, Bhabha Atomic Research Centre, Mumbai-400094, India
| | - Aruna K. Mora
- Radiation and Photochemistry
Division, Bhabha Atomic Research Centre, Mumbai-400094, India
| | - Sukhendu Nath
- Radiation and Photochemistry
Division, Bhabha Atomic Research Centre, Mumbai-400094, India
| | - Dipak K. Palit
- Radiation and Photochemistry
Division, Bhabha Atomic Research Centre, Mumbai-400094, India
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13
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Glover SD, Parada GA, Markle TF, Ott S, Hammarström L. Isolating the Effects of the Proton Tunneling Distance on Proton-Coupled Electron Transfer in a Series of Homologous Tyrosine-Base Model Compounds. J Am Chem Soc 2017; 139:2090-2101. [DOI: 10.1021/jacs.6b12531] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Starla D. Glover
- Department of Chemistry−Ångström, Uppsala University, Box
532, SE-751 20, Uppsala, Sweden
| | - Giovanny A. Parada
- Department of Chemistry−Ångström, Uppsala University, Box
532, SE-751 20, Uppsala, Sweden
| | - Todd F. Markle
- Department of Chemistry−Ångström, Uppsala University, Box
532, SE-751 20, Uppsala, Sweden
| | - Sascha Ott
- Department of Chemistry−Ångström, Uppsala University, Box
532, SE-751 20, Uppsala, Sweden
| | - Leif Hammarström
- Department of Chemistry−Ångström, Uppsala University, Box
532, SE-751 20, Uppsala, Sweden
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14
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Manbeck GF, Fujita E, Concepcion JJ. Proton-Coupled Electron Transfer in a Strongly Coupled Photosystem II-Inspired Chromophore–Imidazole–Phenol Complex: Stepwise Oxidation and Concerted Reduction. J Am Chem Soc 2016; 138:11536-49. [DOI: 10.1021/jacs.6b03506] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gerald F. Manbeck
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Etsuko Fujita
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Javier J. Concepcion
- Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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15
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Miller DC, Tarantino KT, Knowles RR. Proton-Coupled Electron Transfer in Organic Synthesis: Fundamentals, Applications, and Opportunities. Top Curr Chem (Cham) 2016; 374:30. [PMID: 27573270 PMCID: PMC5107260 DOI: 10.1007/s41061-016-0030-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/21/2016] [Indexed: 10/21/2022]
Abstract
Proton-coupled electron transfers (PCETs) are unconventional redox processes in which both protons and electrons are exchanged, often in a concerted elementary step. While PCET is now recognized to play a central a role in biological redox catalysis and inorganic energy conversion technologies, its applications in organic synthesis are only beginning to be explored. In this chapter, we aim to highlight the origins, development, and evolution of the PCET processes most relevant to applications in organic synthesis. Particular emphasis is given to the ability of PCET to serve as a non-classical mechanism for homolytic bond activation that is complimentary to more traditional hydrogen atom transfer processes, enabling the direct generation of valuable organic radical intermediates directly from their native functional group precursors under comparatively mild catalytic conditions. The synthetically advantageous features of PCET reactivity are described in detail, along with examples from the literature describing the PCET activation of common organic functional groups.
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Affiliation(s)
- David C Miller
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Kyle T Tarantino
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA
| | - Robert R Knowles
- Department of Chemistry, Princeton University, Princeton, NJ, 08544, USA.
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16
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MacAleese L, Hermelin S, Hage KE, Chouzenoux P, Kulesza A, Antoine R, Bonacina L, Meuwly M, Wolf JP, Dugourd P. Sequential Proton Coupled Electron Transfer (PCET): Dynamics Observed over 8 Orders of Magnitude in Time. J Am Chem Soc 2016; 138:4401-7. [DOI: 10.1021/jacs.5b12587] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Luke MacAleese
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon 69622 Villeurbanne
cedex, France
| | - Sylvain Hermelin
- Group
of Applied Physics (GAP) Biophotonics, Université de Genève, Chemin
de Pinchat 22, CH-1211 Geneva, Switzerland
| | - Krystel El Hage
- Department
of Chemistry, University of Basel, Klingelbergstr 80, CH-4056 Basel, Switzerland
| | - Pierre Chouzenoux
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon 69622 Villeurbanne
cedex, France
| | - Alexander Kulesza
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon 69622 Villeurbanne
cedex, France
| | - Rodolphe Antoine
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon 69622 Villeurbanne
cedex, France
| | - Luigi Bonacina
- Group
of Applied Physics (GAP) Biophotonics, Université de Genève, Chemin
de Pinchat 22, CH-1211 Geneva, Switzerland
| | - Markus Meuwly
- Department
of Chemistry, University of Basel, Klingelbergstr 80, CH-4056 Basel, Switzerland
| | - Jean-Pierre Wolf
- Group
of Applied Physics (GAP) Biophotonics, Université de Genève, Chemin
de Pinchat 22, CH-1211 Geneva, Switzerland
| | - Philippe Dugourd
- Institut
Lumière Matière, UMR5306 Université Claude Bernard
Lyon1-CNRS, Université de Lyon 69622 Villeurbanne
cedex, France
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17
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Affiliation(s)
- Susanta K. Sen Gupta
- Department of Chemistry, Faculty of Science; Banaras Hindu University; Varanasi 221005 India
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18
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Rosenthal J. Progress Toward the Electrocatalytic Production of Liquid Fuels from Carbon Dioxide. PROGRESS IN INORGANIC CHEMISTRY: VOLUME 59 2014. [DOI: 10.1002/9781118869994.ch04] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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19
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Ferrocenyl-amidinium compound as building block for aqueous proton-coupled electron transfer studies. INORG CHEM COMMUN 2014. [DOI: 10.1016/j.inoche.2014.02.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Samanta SK, Bhattacharya S. Wide-Range Light-Harvesting Donor-Acceptor Assemblies through Specific Intergelator Interactions via Self-Assembly. Chemistry 2012; 18:15875-85. [DOI: 10.1002/chem.201103855] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 07/13/2012] [Indexed: 11/10/2022]
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21
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Weinberg DR, Gagliardi CJ, Hull JF, Murphy CF, Kent CA, Westlake BC, Paul A, Ess DH, McCafferty DG, Meyer TJ. Proton-Coupled Electron Transfer. Chem Rev 2012; 112:4016-93. [DOI: 10.1021/cr200177j] [Citation(s) in RCA: 1125] [Impact Index Per Article: 93.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- David R. Weinberg
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
- Department of Physical and Environmental
Sciences, Colorado Mesa University, 1100 North Avenue, Grand Junction,
Colorado 81501-3122, United States
| | - Christopher J. Gagliardi
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Jonathan F. Hull
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Christine Fecenko Murphy
- Department
of Chemistry, B219
Levine Science Research Center, Box 90354, Duke University, Durham,
North Carolina 27708-0354, United States
| | - Caleb A. Kent
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Brittany C. Westlake
- The American Chemical Society,
1155 Sixteenth Street NW, Washington, District of Columbia 20036,
United States
| | - Amit Paul
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Daniel H. Ess
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Dewey Granville McCafferty
- Department
of Chemistry, B219
Levine Science Research Center, Box 90354, Duke University, Durham,
North Carolina 27708-0354, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
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22
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Ghosh HN, Adamczyk K, Verma S, Dreyer J, Nibbering ETJ. On the role of hydrogen bonds in photoinduced electron-transfer dynamics between 9-fluorenone and amine solvents. Chemistry 2012; 18:4930-7. [PMID: 22389093 DOI: 10.1002/chem.201102994] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 12/23/2011] [Indexed: 11/09/2022]
Abstract
Using ultrafast fluorescence upconversion and mid-infrared spectroscopy, we explore the role of hydrogen bonds in the photoinduced electron transfer (ET) between 9-fluorenone (FLU) and the solvents trimethylamine (TEA) and dimethylamine (DEA). FLU shows hydrogen-bond dynamics in the methanol solvent upon photoexcitation, and similar effects may be anticipated when using DEA, whereas no hydrogen bonds can occur in TEA. Photoexcitation of the electron-acceptor dye molecule FLU with a 400 nm pump pulse induces ultrafast ET from the amine solvents, which is followed by 100 fs IR probe pulses as well as fluorescence upconversion, monitoring the time evolution of marker bands of the FLU S(1) state and the FLU radical anion, and an overtone band of the amine solvent, marking the transient generation of the amine radical cation. A comparison of the experimentally determined forward charge-separation and backward charge-recombination rates for the FLU-TEA and FLU-DEA reaction systems with the driving-force dependencies calculated for the forward and backward ET rates reveals that additional degrees of freedom determine the ET reaction dynamics for the FLU-DEA system. We suggest that hydrogen bonding between the DEA molecules plays a key role in this behaviour.
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Affiliation(s)
- Hirendra N Ghosh
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
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23
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Young ER, Rosenthal J, Nocera DG. Energy transfer mediated by asymmetric hydrogen-bonded interfaces. Chem Sci 2012; 3:10.1039/C1SC00596K. [PMID: 24363889 PMCID: PMC3868475 DOI: 10.1039/c1sc00596k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Amidine-appended ferrocene derivatives form a supramolecular assembly with Ru(ii)(bpy-COOH) (L)22+ complexes (bpy-COOH is 4-CO2H-4'-CH3-bpy and L = bpy, 2,2'-bipyridine or btfmbpy, 4,4'-bis (trifluoromethyl)-2,2'-bipyridine). Steady-state, time-resolved spectroscopy and kinetic isotope effects establish that the metal-to-ligand charge transfer excited states of the Ru(ii) complexes are quenched by proton-coupled energy transfer (PCEnT). These results show that proton motion can be effective in mediating not only electron transfer (ET) but energy transfer (EnT) as well.
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Affiliation(s)
- Elizabeth R Young
- Department of Chemistry, Amherst College, P.O. Box 5000, Amherst, MA, 01002-5000, USA
| | - Joel Rosenthal
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA
| | - Daniel G Nocera
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139-4307, USA. ; Tel: +1 617 253 5537
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24
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Otsuki J. Energy transfer in non-covalent porphyrin assemblies: through-space or through-bond? J PORPHYR PHTHALOCYA 2012. [DOI: 10.1142/s1088424609001376] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Photosynthetic antenna arrays found in nature funnel photoexcited energy into the reaction center. Attempts have been made to mimic the antenna function by using artificial chromophores, porphyrins in particular, not only to better understand the energy-transfer processes but also to create light-harvesting devices. This review covers non-covalent porphyrin assemblies, for which intra-ensemble energy-transfer processes were characterized. The essence of the mechanisms of energy transfer is summarized and specific examples are reviewed with an emphasis put on the rate and mechanism of singlet-singlet energy transfer. As these examples demonstrate, non-covalent intra-ensemble energy-transfer processes have been ascribed to the Förster-type through-space mechanism in almost all cases. The exception is porphyrin dyad and pentad from our group based on amidinium-carboxylate salt bridges. Through-bond superexchange mechanism is proposed to account for the fast excited energy-transfer processes for these unique assemblies. The importance of intermolecular interactions not only in terms of the structural aspects but also in terms of the electronic aspects is highlighted for the design of supramolecular systems in which efficient energy transfer is desired.
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Affiliation(s)
- Joe Otsuki
- College of Science and Technology, Nihon University, 1-8-14 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308, Japan
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25
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Wang KR, Guo DS, Jiang BP, Liu Y. Excitonic coupling interactions in the self-assembly of perylene-bridged bis(β-cyclodextrin)s and porphyrin. Chem Commun (Camb) 2012; 48:3644-6. [DOI: 10.1039/c2cc17786b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Bai X, Ning M, Brown RE. Electron and Hydrogen Transfer in Small Hydrogen Fluoride Anion Clusters. J Phys Chem A 2011; 115:10596-9. [DOI: 10.1021/jp202968n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Xin Bai
- Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Ming Ning
- Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
| | - Richard E. Brown
- Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States
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27
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Theory of proton coupled electron transfer reactions: Assessing the Born–Oppenheimer approximation for the proton motion using an analytically solvable model. Chem Phys 2011. [DOI: 10.1016/j.chemphys.2010.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Du B, Stern C, Harvey PD. Singlet and triplet energy transfer rate acceleration by additions of clusters in supramolecular pigment-organometallic cluster assemblies. Chem Commun (Camb) 2011; 47:6072-4. [DOI: 10.1039/c1cc11174d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Ghosh HN, Verma S, Nibbering ETJ. Ultrafast Forward and Backward Electron Transfer Dynamics of Coumarin 337 in Hydrogen-Bonded Anilines As Studied with Femtosecond UV-Pump/IR-Probe Spectroscopy. J Phys Chem A 2010; 115:664-70. [DOI: 10.1021/jp108090b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Hirendra N. Ghosh
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai −400085, India
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max Born Strasse 2A, D-12489, Berlin, Germany
| | - Sandeep Verma
- Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Trombay Mumbai −400085, India
| | - Erik T. J. Nibbering
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max Born Strasse 2A, D-12489, Berlin, Germany
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30
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Costentin C, Robert M, Savéant JM. Update 1 of: Electrochemical Approach to the Mechanistic Study of Proton-Coupled Electron Transfer. Chem Rev 2010; 110:PR1-40. [DOI: 10.1021/cr100038y] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Cyrille Costentin
- Laboratoire d’Electrochimie Moléculaire, Unité Mixte de Recherche Université, CNRS No. 7591, Université Paris Diderot, 15 rue Jean de Baïf, 75013 Paris, France
- This is a Chemical Reviews Perennial Review. The root paper of this title was published in Chem. Rev. 2008, 108 (7), 2145−2179, DOI: 10.1021/cr068065t; Published (Web) July 11, 2008. Updates to the text appear in red type
| | - Marc Robert
- Laboratoire d’Electrochimie Moléculaire, Unité Mixte de Recherche Université, CNRS No. 7591, Université Paris Diderot, 15 rue Jean de Baïf, 75013 Paris, France
- This is a Chemical Reviews Perennial Review. The root paper of this title was published in Chem. Rev. 2008, 108 (7), 2145−2179, DOI: 10.1021/cr068065t; Published (Web) July 11, 2008. Updates to the text appear in red type
| | - Jean-Michel Savéant
- Laboratoire d’Electrochimie Moléculaire, Unité Mixte de Recherche Université, CNRS No. 7591, Université Paris Diderot, 15 rue Jean de Baïf, 75013 Paris, France
- This is a Chemical Reviews Perennial Review. The root paper of this title was published in Chem. Rev. 2008, 108 (7), 2145−2179, DOI: 10.1021/cr068065t; Published (Web) July 11, 2008. Updates to the text appear in red type
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31
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Chen X, Xing D, Zhang L, Cukier RI, Bu Y. Effect of metal ions on radical type and proton-coupled electron transfer channel: σ-Radical vs π-radical and σ-channel vs π-channel in the imide units. J Comput Chem 2009; 30:2694-705. [DOI: 10.1002/jcc.21284] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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32
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Johannissen LO, Irebo T, Sjödin M, Johansson O, Hammarström L. The Kinetic Effect of Internal Hydrogen Bonds on Proton-Coupled Electron Transfer from Phenols: A Theoretical Analysis with Modeling of Experimental Data. J Phys Chem B 2009; 113:16214-25. [DOI: 10.1021/jp9048633] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Linus O. Johannissen
- Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Tania Irebo
- Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Martin Sjödin
- Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Olof Johansson
- Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Leif Hammarström
- Department of Photochemistry and Molecular Science, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
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33
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Abstract
Personalized energy (PE) is a transformative idea that provides a new modality for the planet's energy future. By providing solar energy to the individual, an energy supply becomes secure and available to people of both legacy and nonlegacy worlds and minimally contributes to an increase in the anthropogenic level of carbon dioxide. Because PE will be possible only if solar energy is available 24 h a day, 7 days a week, the key enabler for solar PE is an inexpensive storage mechanism. HY (Y = halide or OH(-)) splitting is a fuel-forming reaction of sufficient energy density for large-scale solar storage, but the reaction relies on chemical transformations that are not understood at the most basic science level. Critical among these are multielectron transfers that are proton-coupled and involve the activation of bonds in energy-poor substrates. The chemistry of these three italicized areas is developed, and from this platform, discovery paths leading to new hydrohalic acid- and water-splitting catalysts are delineated. The latter water-splitting catalyst captures many of the functional elements of photosynthesis. In doing so, a highly manufacturable and inexpensive method for solar PE storage has been discovered.
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Affiliation(s)
- Daniel G Nocera
- Department of Chemistry, 6-335, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA.
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34
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Wang YF, Yang G, Liu CB. Electron transfers in proteins: investigations with a modified through-bond coupling model. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:021927. [PMID: 19792171 DOI: 10.1103/physreve.80.021927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 07/15/2009] [Indexed: 05/28/2023]
Abstract
By integrating the merits of previous models, a modified through-bond coupling (MTBC) model is proposed in this work and shows obvious improvement compared with previous models. With the MTBC model, the dominant electron coupling pathways in the polypeptide chains were identified, where the N-H bonds were found to be essential to the electron couplings. The local structures of peptides and proteins were finely characterized by the electron couplings and decay factors since they are structure sensitive. The neighboring carbonyl O-O distances are qualitatively correlated with the decay factors, and the deviations from the transconfigurations will weaken the coupling interactions. When the two amino acids being studied are not close in sequence, the couplings through hydrogen bonds are probably the main pathway because the electron transfers in this way save many steps, albeit the decay factor is less than that of per bond, consistent with the classical electron-tunneling model developed by Beratan [Science 252, 1285 (1991)]. It was found that the MTBC model can be effectively extended to study the electron transfers in complex biological systems with the combination of the fragment approach, which takes into account the contributions of key hydrogen bonds.
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Affiliation(s)
- Ye-Fei Wang
- Institute of Theoretical Chemistry, Shandong University, Jinan, 250100 Shandong, People's Republic of China
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35
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Reece SY, Nocera DG. Proton-coupled electron transfer in biology: results from synergistic studies in natural and model systems. Annu Rev Biochem 2009; 78:673-99. [PMID: 19344235 DOI: 10.1146/annurev.biochem.78.080207.092132] [Citation(s) in RCA: 361] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Proton-coupled electron transfer (PCET) underpins energy conversion in biology. PCET may occur with the unidirectional or bidirectional transfer of a proton and electron and may proceed synchronously or asynchronously. To illustrate the role of PCET in biology, this review presents complementary biological and model systems that explore PCET in electron transfer (ET) through hydrogen bonds [azurin as compared to donor-acceptor (D-A) hydrogen-bonded networks], the activation of C-H bonds [alcohol dehydrogenase and soybean lipoxygenase (SLO) as compared to Fe(III) metal complexes], and the generation and transport of amino acid radicals [photosystem II (PSII) and ribonucleotide reductase (RNR) as compared to tyrosine-modified photoactive Re(I) and Ru(II) complexes]. In providing these comparisons, the fundamental principles of PCET in biology are illustrated in a tangible way.
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Affiliation(s)
- Steven Y Reece
- Department of Chemistry, Massachusetts Institutes of Technology, Cambridge, MA 02139-4307, USA
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36
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Young ER, Rosenthal J, Hodgkiss JM, Nocera DG. Comparative PCET study of a donor-acceptor pair linked by ionized and nonionized asymmetric hydrogen-bonded interfaces. J Am Chem Soc 2009; 131:7678-84. [PMID: 19489645 DOI: 10.1021/ja809777j] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A Zn(II) amidinium porphyrin is the excited-state electron donor (D) to a naphthalene diimide acceptor (A) appended with either a carboxylate or sulfonate functionality. The two-point hydrogen bond (...[H(+)]...) formed between the amidinium and carboxylate or sulfonate functionalities establishes a proton-coupled electron transfer (PCET) pathway for charge transfer. The two D...[H(+)]...A assemblies differ only by the proton configuration within the hydrogen-bonding interface. Specifically, the amidinium ion transfers a proton to the carboxylate to form a nonionized amidine-carboxylic acid two-point hydrogen network, whereas the amidinium retains both protons when bound to the sulfonate functionality, forming an ionized amidinium-sulfonate two-point hydrogen bond network. These two interface configurations within the dyads thus allow for a direct comparison of the PCET kinetics for the same donor and acceptor juxtaposed by ionized and nonionized hydrogen-bonded interfaces. Analysis of the PCET kinetics ascertained from transient absorption and transient emission spectroscopy reveals that the ionized interface is more strongly impacted by the local solvent environment, thus establishing that the initial static configuration of the proton interface is a critical determinant in the kinetics of PCET.
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Affiliation(s)
- Elizabeth R Young
- Department of Chemistry, 6-335, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA
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37
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Chakrabarti S, Parker MFL, Morgan CW, Schafmeister CE, Waldeck DH. Experimental evidence for water mediated electron transfer through bis-amino acid donor-bridge-acceptor oligomers. J Am Chem Soc 2009; 131:2044-5. [PMID: 19173584 DOI: 10.1021/ja8079324] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This work compares the photoinduced unimolecular electron transfer rate constants for two different solute molecules (D-SSS-A and D-SRR-A) in water and DMSO solvents. The D-SSS-A solute has a cleft between the electron donor and acceptor units, which is able to contain a water molecule but is too small for DMSO. The rate constant for D-SSS-A in water is significantly higher than that for D-SRR-A, which lacks a cleft, and significantly higher for either solute in DMSO. The enhancement of the rate constant is explained by an electron tunneling pathway that involves water molecule(s).
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Affiliation(s)
- Subhasis Chakrabarti
- University of Pittsburgh, Department of Chemistry, Pittsburgh, Pennsylvania 15260, USA
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38
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Wu A, Mayer JM. Hydrogen atom transfer reactions of a ruthenium imidazole complex: hydrogen tunneling and the applicability of the Marcus cross relation. J Am Chem Soc 2008; 130:14745-54. [PMID: 18841973 PMCID: PMC2633126 DOI: 10.1021/ja805067h] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction of Ru(II)(acac)2(py-imH) (Ru(II)imH) with TEMPO(*) (2,2,6,6-tetramethylpiperidine-1-oxyl radical) in MeCN quantitatively gives Ru(III)(acac)2(py-im) (Ru(III)im) and the hydroxylamine TEMPO-H by transfer of H(*) (H(+) + e(-)) (acac = 2,4-pentanedionato, py-imH = 2-(2'-pyridyl)imidazole). Kinetic measurements of this reaction by UV-vis stopped-flow techniques indicate a bimolecular rate constant k(3H) = 1400 +/- 100 M(-1) s(-1) at 298 K. The reaction proceeds via a concerted hydrogen atom transfer (HAT) mechanism, as shown by ruling out the stepwise pathways of initial proton or electron transfer due to their very unfavorable thermochemistry (Delta G(o)). Deuterium transfer from Ru(II)(acac)2(py-imD) (Ru(II)imD) to TEMPO(*) is surprisingly much slower at k(3D) = 60 +/- 7 M(-1) s(-1), with k(3H)/k(3D) = 23 +/- 3 at 298 K. Temperature-dependent measurements of this deuterium kinetic isotope effect (KIE) show a large difference between the apparent activation energies, E(a3D) - E(a3H) = 1.9 +/- 0.8 kcal mol(-1). The large k(3H)/k(3D) and DeltaE(a) values appear to be greater than the semiclassical limits and thus suggest a tunneling mechanism. The self-exchange HAT reaction between Ru(II)imH and Ru(III)im, measured by (1)H NMR line broadening, occurs with k(4H) = (3.2 +/- 0.3) x 10(5) M(-1) s(-1) at 298 K and k(4H)/k(4D) = 1.5 +/- 0.2. Despite the small KIE, tunneling is suggested by the ratio of Arrhenius pre-exponential factors, log(A(4H)/A(4D)) = -0.5 +/- 0.3. These data provide a test of the applicability of the Marcus cross relation for H and D transfers, over a range of temperatures, for a reaction that involves substantial tunneling. The cross relation calculates rate constants for Ru(II)imH(D) + TEMPO(*) that are greater than those observed: k(3H,calc)/k(3H) = 31 +/- 4 and k(3D,calc)/k(3D) = 140 +/- 20 at 298 K. In these rate constants and in the activation parameters, there is a better agreement with the Marcus cross relation for H than for D transfer, despite the greater prevalence of tunneling for H. The cross relation does not explicitly include tunneling, so close agreement should not be expected. In light of these results, the strengths and weaknesses of applying the cross relation to HAT reactions are discussed.
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Affiliation(s)
- Adam Wu
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, WA, 98195-1700, USA
| | - James M. Mayer
- Department of Chemistry, University of Washington, Campus Box 351700, Seattle, WA, 98195-1700, USA
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39
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Hay S, Scrutton NS. H-transfers in Photosystem II: what can we learn from recent lessons in the enzyme community? PHOTOSYNTHESIS RESEARCH 2008; 98:169-177. [PMID: 18766465 DOI: 10.1007/s11120-008-9326-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 06/28/2008] [Indexed: 05/26/2023]
Abstract
Over the last 10 years, studies of enzyme systems have demonstrated that, in many cases, H-transfers occur by a quantum mechanical tunneling mechanism analogous to long-range electron transfer. H-transfer reactions can be described by an extension of Marcus theory and, by substituting hydrogen with deuterium (or even tritium), it is possible to explore this theory in new ways by employing kinetic isotope effects. Because hydrogen has a relatively short deBroglie wavelength, H-transfers are controlled by the width of the reaction barrier. By coupling protein dynamics to the reaction coordinate, enzymes have the potential ability to facilitate more efficient H-tunneling by modulating barrier properties. In this review, we describe recent advances in both experimental and theoretical studies of enzymatic H-transfer, in particular the role of protein dynamics or promoting motions. We then discuss possible consequences with regard to tyrosine oxidation/reduction kinetics in Photosystem II.
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Affiliation(s)
- Sam Hay
- Manchester Interdisciplinary Biocentre and Faculty of Life Sciences, University of Manchester, Manchester, UK.
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40
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Petersen PB, Roberts ST, Ramasesha K, Nocera DG, Tokmakoff A. Ultrafast N-H vibrational dynamics of cyclic doubly hydrogen-bonded homo- and heterodimers. J Phys Chem B 2008; 112:13167-71. [PMID: 18821789 DOI: 10.1021/jp805338h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hydrogen-bonded interfaces are essential structural elements in biology. Furthermore, they can mediate electron transport by coupling the electron to proton transfer within the interface. The specific hydrogen-bonding configuration and strength have a large impact on the proton transfer, which exchanges the hydrogen-bonded donor and acceptor species (i.e., NH...O --> N...HO). Modulations of the hydrogen-bonding environment, such as the hydrogen-bond stretch and twist modes, affect the proton-transfer dynamics. Here, we present transient grating and echo peak shift measurements of the NH stretch vibrations of four doubly hydrogen-bonded cyclic dimers in their electronic ground state. The equilibrium vibrational dynamics exhibit strong coherent modulations that we attribute to coupling of the high-frequency NH vibration to the low-frequency interdimer stretch and twist modes and not to interference between multiple Fermi resonances that dominate the substructure of the linear spectra.
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MacLean PD, Chapman EE, Dobrowolski SL, Thompson A, Barclay LRC. Pyrroles As Antioxidants: Solvent Effects and the Nature of the Attacking Radical on Antioxidant Activities and Mechanisms of Pyrroles, Dipyrrinones, and Bile Pigments. J Org Chem 2008; 73:6623-35. [DOI: 10.1021/jo8005073] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Patricia D. MacLean
- Department of Chemistry, Mount Allison University, Sackville, New Brunswick, Canada E4L 1G8, and Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J3
| | - Erin E. Chapman
- Department of Chemistry, Mount Allison University, Sackville, New Brunswick, Canada E4L 1G8, and Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J3
| | - Sarah L. Dobrowolski
- Department of Chemistry, Mount Allison University, Sackville, New Brunswick, Canada E4L 1G8, and Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J3
| | - Alison Thompson
- Department of Chemistry, Mount Allison University, Sackville, New Brunswick, Canada E4L 1G8, and Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J3
| | - L. Ross C. Barclay
- Department of Chemistry, Mount Allison University, Sackville, New Brunswick, Canada E4L 1G8, and Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J3
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42
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Costentin C. Electrochemical Approach to the Mechanistic Study of Proton-Coupled Electron Transfer. Chem Rev 2008; 108:2145-79. [DOI: 10.1021/cr068065t] [Citation(s) in RCA: 328] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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43
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Irebo T, Johansson O, Hammarström L. The Rate Ladder of Proton-Coupled Tyrosine Oxidation in Water: A Systematic Dependence on Hydrogen Bonds and Protonation State. J Am Chem Soc 2008; 130:9194-5. [DOI: 10.1021/ja802076v] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Tania Irebo
- Department of Photochemistry and Molecular Science, Uppsala University Box 523, SE-751 20 Uppsala, Sweden
| | - Olof Johansson
- Department of Photochemistry and Molecular Science, Uppsala University Box 523, SE-751 20 Uppsala, Sweden
| | - Leif Hammarström
- Department of Photochemistry and Molecular Science, Uppsala University Box 523, SE-751 20 Uppsala, Sweden
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44
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Betley TA, Wu Q, Van Voorhis T, Nocera DG. Electronic design criteria for O-O bond formation via metal-oxo complexes. Inorg Chem 2008; 47:1849-61. [PMID: 18330975 DOI: 10.1021/ic701972n] [Citation(s) in RCA: 296] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Metal-oxos are critical intermediates for the management of oxygen and its activation. The reactivity of the metal-oxo is central to the formation of O-O bonds, which is the essential step for oxygen generation. Two basic strategies for the formation of O-O bonds at metal-oxo active sites are presented. The acid-base (AB) strategy involves the attack of a nucleophilic oxygen species (e.g., hydroxide) on an electrophilic metal-oxo. Here, active-site designs must incorporate the assembly of a hydroxide (or water) proximate to a high-valent metal-oxo of even d electron count. For the radical coupling (RC) strategy, two high-valent metal-oxos of an odd d electron count are needed to drive O-O coupling. This Forum Article focuses on the different electronic structures of terminal metal-oxos that support AB and RC strategies and the design of ligand scaffolds that engender these electronic structures.
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Affiliation(s)
- Theodore A Betley
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA
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Otsuki J, Kanazawa Y, Kaito A, Shafiqul Islam DM, Araki Y, Ito O. Through-Bond Excited Energy Transfer Mediated by an Amidinium–Carboxylate Salt Bridge in Zn–Porphyrin Free-Base Porphyrin Dyads. Chemistry 2008; 14:3776-84. [DOI: 10.1002/chem.200701486] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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46
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Young ER, Rosenthal J, Nocera DG. Spectral observation of conversion between ionized vs. non-ionized proton-coupled electron transfer interfaces. Chem Commun (Camb) 2008:2322-4. [PMID: 18473057 DOI: 10.1039/b717747j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-point hydrogen bonding between acid and base functionalities provides a convenient method for the modular assembly of proton-coupled electron transfer (PCET) networks, especially when that interface comprises an amidinium and two-point anionic partner; a system is presented that permits the proton configuration within the interface to be determined when pK(a) values of the conjugate acids are known.
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Affiliation(s)
- Elizabeth R Young
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA
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47
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Yuasa J, Yamada S, Fukuzumi S. One-step versus stepwise mechanism in protonated amino acid-promoted electron-transfer reduction of a quinone by electron donors and two-electron reduction by a dihydronicotinamide adenine dinucleotide analogue. Interplay between electron transfer and hydrogen bonding. J Am Chem Soc 2008; 130:5808-20. [PMID: 18386924 DOI: 10.1021/ja8001452] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Semiquinone radical anion of 1-(p-tolylsulfinyl)-2,5-benzoquinone (TolSQ(*-)) forms a strong hydrogen bond with protonated histidine (TolSQ(*-)/His x 2 H(+)), which was successfully detected by electron spin resonance. Strong hydrogen bonding between TolSQ(*-) and His x 2 H(+) results in acceleration of electron transfer (ET) from ferrocenes [R2Fc, R = C5H5, C5H4(n-Bu), C5H4Me] to TolSQ, when the one-electron reduction potential of TolSQ is largely shifted to the positive direction in the presence of His x 2 H(+). The rates of His x 2 H(+)-promoted ET from R2Fc to TolSQ exhibit deuterium kinetic isotope effects due to partial dissociation of the N-H bond in His x 2 H(+) at the transition state, when His x 2 H(+) is replaced by the deuterated compound (His x 2 D(+)-d6). The observed deuterium kinetic isotope effect (kH/kD) decreases continuously with increasing the driving force of ET to approach kH/kD = 1.0. On the other hand, His x 2 H(+) also promotes a hydride reduction of TolSQ by an NADH analogue, 9,10-dihydro-10-methylacridine (AcrH2). The hydride reduction proceeds via the one-step hydride-transfer pathway. In such a case, a large deuterium kinetic isotope effect is observed in the rate of the hydride transfer, when AcrH2 is replaced by the dideuterated compound (AcrD2). In sharp contrast to this, no deuterium kinetic isotope effect is observed, when His x 2 H(+) is replaced by His x 2 D(+)-d6. On the other hand, direct protonation of TolSQ and 9,10-phenanthrenequinone (PQ) also results in efficient reductions of TolSQH(+) and PQH(+) by AcrH2, respectively. In this case, however, the hydride-transfer reactions occur via the ET pathway, that is, ET from AcrH2 to TolSQH(+) and PQH(+) occurs in preference to direct hydride transfer from AcrH2 to TolSQH(+) and PQH(+), respectively. The AcrH2(*+) produced by the ET oxidation of AcrH2 by TolSQH(+) and PQH(+) was directly detected by using a stopped-flow technique.
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Affiliation(s)
- Junpei Yuasa
- Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency, Suita, Osaka 565-0871, Japan
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Betley TA, Surendranath Y, Childress MV, Alliger GE, Fu R, Cummins CC, Nocera DG. A ligand field chemistry of oxygen generation by the oxygen-evolving complex and synthetic active sites. Philos Trans R Soc Lond B Biol Sci 2008; 363:1293-303; discussion 1303. [PMID: 17971328 PMCID: PMC2614088 DOI: 10.1098/rstb.2007.2226] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Oxygen-oxygen bond formation and O2 generation occur from the S4 state of the oxygen-evolving complex (OEC). Several mechanistic possibilities have been proposed for water oxidation, depending on the formal oxidation state of the Mn atoms. All fall under two general classifications: the AB mechanism in which nucleophilic oxygen (base, B) attacks electrophilic oxygen (acid, A) of the Mn4Ca cluster or the RC mechanism in which radical-like oxygen species couple within OEC. The critical intermediate in either mechanism involves a metal oxo, though the nature of this oxo for AB and RC mechanisms is disparate. In the case of the AB mechanism, assembly of an even-electron count, high-valent metal-oxo proximate to a hydroxide is needed whereas, in an RC mechanism, two odd-electron count, high-valent metal oxos are required. Thus the two mechanisms give rise to very different design criteria for functional models of the OEC active site. This discussion presents the electron counts and ligand geometries that support metal oxos for AB and RC O-O bond-forming reactions. The construction of architectures that bring two oxygen functionalities together under the purview of the AB and RC scenarios are described.
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Affiliation(s)
| | | | | | | | | | | | - Daniel G Nocera
- Department of Chemistry, Massachusetts Institute of Technology77 Massachusetts Avenue, 6-335, Cambridge, MA 02139-4307, USA
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Abstract
Energy is the most important issue of the 21st century. About 85% of our energy comes from fossil fuels, a finite resource unevenly distributed beneath the Earth's surface. Reserves of fossil fuels are progressively decreasing, and their continued use produces harmful effects such as pollution that threatens human health and greenhouse gases associated with global warming. Prompt global action to solve the energy crisis is therefore needed. To pursue such an action, we are urged to save energy and to use energy in more efficient ways, but we are also forced to find alternative energy sources, the most convenient of which is solar energy for several reasons. The sun continuously provides the Earth with a huge amount of energy, fairly distributed all over the world. Its enormous potential as a clean, abundant, and economical energy source, however, cannot be exploited unless it is converted into useful forms of energy. This Review starts with a brief description of the mechanism at the basis of the natural photosynthesis and, then, reports the results obtained so far in the field of photochemical conversion of solar energy. The "grand challenge" for chemists is to find a convenient means for artificial conversion of solar energy into fuels. If chemists succeed to create an artificial photosynthetic process, "... life and civilization will continue as long as the sun shines!", as the Italian scientist Giacomo Ciamician forecast almost one hundred years ago.
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Affiliation(s)
- Vincenzo Balzani
- Dipartimento di Chimica "G. Ciamician", Università di Bologna, Via Selmi 2 40126 Bologna, Italy.
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Affiliation(s)
- My Hang V Huynh
- DE-1: High Explosive Science and Technology Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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