1
|
Ennist NM, Wang S, Kennedy MA, Curti M, Sutherland GA, Vasilev C, Redler RL, Maffeis V, Shareef S, Sica AV, Hua AS, Deshmukh AP, Moyer AP, Hicks DR, Swartz AZ, Cacho RA, Novy N, Bera AK, Kang A, Sankaran B, Johnson MP, Phadkule A, Reppert M, Ekiert D, Bhabha G, Stewart L, Caram JR, Stoddard BL, Romero E, Hunter CN, Baker D. De novo design of proteins housing excitonically coupled chlorophyll special pairs. Nat Chem Biol 2024; 20:906-915. [PMID: 38831036 PMCID: PMC11213709 DOI: 10.1038/s41589-024-01626-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 04/15/2024] [Indexed: 06/05/2024]
Abstract
Natural photosystems couple light harvesting to charge separation using a 'special pair' of chlorophyll molecules that accepts excitation energy from the antenna and initiates an electron-transfer cascade. To investigate the photophysics of special pairs independently of the complexities of native photosynthetic proteins, and as a first step toward creating synthetic photosystems for new energy conversion technologies, we designed C2-symmetric proteins that hold two chlorophyll molecules in closely juxtaposed arrangements. X-ray crystallography confirmed that one designed protein binds two chlorophylls in the same orientation as native special pairs, whereas a second designed protein positions them in a previously unseen geometry. Spectroscopy revealed that the chlorophylls are excitonically coupled, and fluorescence lifetime imaging demonstrated energy transfer. The cryo-electron microscopy structure of a designed 24-chlorophyll octahedral nanocage with a special pair on each edge closely matched the design model. The results suggest that the de novo design of artificial photosynthetic systems is within reach of current computational methods.
Collapse
Affiliation(s)
- Nathan M Ennist
- Institute for Protein Design, University of Washington, Seattle, WA, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
| | - Shunzhi Wang
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Madison A Kennedy
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Mariano Curti
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Tarragona, Spain
| | | | | | - Rachel L Redler
- Department of Cell Biology and Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
| | - Valentin Maffeis
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Tarragona, Spain
| | - Saeed Shareef
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Tarragona, Spain
- Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Tarragona, Spain
| | - Anthony V Sica
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Ash Sueh Hua
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Arundhati P Deshmukh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Adam P Moyer
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Derrick R Hicks
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Avi Z Swartz
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Ralph A Cacho
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Nathan Novy
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Asim K Bera
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Alex Kang
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Amala Phadkule
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Mike Reppert
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Damian Ekiert
- Department of Cell Biology and Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Gira Bhabha
- Department of Cell Biology and Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
| | - Lance Stewart
- Institute for Protein Design, University of Washington, Seattle, WA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Justin R Caram
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Elisabet Romero
- Institute of Chemical Research of Catalonia (ICIQ-CERCA), Barcelona Institute of Science and Technology (BIST), Tarragona, Spain
| | - C Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - David Baker
- Institute for Protein Design, University of Washington, Seattle, WA, USA.
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
| |
Collapse
|
2
|
Begam K, Aksu H, Dunietz BD. Antioxidative Triplet Excitation Energy Transfer in Bacterial Reaction Center Using a Screened Range Separated Hybrid Functional. J Phys Chem B 2024. [PMID: 38687467 DOI: 10.1021/acs.jpcb.3c08501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Excess energy absorbed by photosystems (PSs) can result in photoinduced oxidative damage. Transfer of such energy within the core pigments of the reaction center in the form of triplet excitation is important in regulating and preserving the functionality of PSs. In the bacterial reaction center (BRC), the special pair (P) is understood to act as the electron donor in a photoinduced charge transfer process, triggering the charge separation process through the photoactive branch A pigments that experience a higher polarizing environment. At this work, triplet excitation energy transfer (TEET) in BRC is studied using a computational perspective to gain insights into the roles of the dielectric environment and interpigment orientations. We find in agreement with experimental observations that TEET proceeds through branch B. The TEET process toward branch B pigment is found to be significantly faster than the hypothetical process proceeding through branch A pigments with ps and ms time scales, respectively. Our calculations find that conformational differences play a major role in this branch asymmetry in TEET, where the dielectric environment asymmetry plays only a secondary role in directing the TEET to proceed through branch B. We also address TEET processes asserting the role of carotenoid as the final triplet energy acceptor and in a mutant form, where the branch pigments adjacent to P are replaced by bacteriopheophytins. The necessary electronic excitation energies and electronic state couplings are calculated by the recently developed polarization-consistent framework combining a screened range-separated hybrid functional and a polarizable continuum mode. The polarization-consistent potential energy surfaces are used to parametrize the quantum mechanical approach, implementing Fermi's golden rule expression of the TEET rate calculations.
Collapse
Affiliation(s)
- Khadiza Begam
- Department of Physics, Kent State University, Kent, Ohio 44242, United States
| | - Huseyin Aksu
- Department of Physics, Faculty of Science at Canakkale Onsekiz Mart University, Canakkale 17100, Turkey
| | - Barry D Dunietz
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| |
Collapse
|
3
|
Charge transfer as a mechanism for chlorophyll fluorescence concentration quenching. Proc Natl Acad Sci U S A 2023; 120:e2210811120. [PMID: 36689657 PMCID: PMC9945999 DOI: 10.1073/pnas.2210811120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Highly concentrated solutions of chlorophyll display rapid fluorescence quenching. The same devastating energy loss is not seen in photosynthetic light-harvesting antenna complexes, despite the need for chromophores to be in close proximity to facilitate energy transfer. A promising, though unconfirmed mechanism for the observed quenching is energy transfer from an excited chlorophyll monomer to a closely associated chlorophyll pair that subsequently undergoes rapid nonradiative decay to the ground state via a short-lived intermediate charge-transfer state. In this work, we make use of newly emerging fast methods in quantum chemistry to assess the feasibility of this proposed mechanism. We calculate rate constants for the initial charge separation, based on Marcus free-energy surfaces extracted from molecular dynamics simulations of solvated chlorophyll pairs, demonstrating that this pathway will compete with fluorescence (i.e., drive quenching) at experimentally measured quenching concentrations. We show that the rate of charge separation is highly sensitive to interchlorophyll distance and the relative orientations of chromophores within a quenching pair. We discuss possible solvent effects on the rate of charge separation (and consequently the degree of quenching), using the light-harvesting complex II (LH2) protein from rps. acidophila as a specific example of how this process might be controlled in a protein environment. Crucially, we reveal that the LH2 antenna protein prevents quenching, even at the high chlorophyll concentrations required for efficient energy transfer, by restricting the range of orientations that neighboring chlorophyll pairs can adopt.
Collapse
|
4
|
Jing H, Liu S, Jiang J, Tran VP, Rong J, Wang P, Lindsey JS. Meso bromination and derivatization of synthetic bacteriochlorins. NEW J CHEM 2022. [DOI: 10.1039/d1nj05853c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Twelve bacteriochlorin building blocks featuring meso-substitution have been prepared including a set with finely tuned long-wavelength absorption (725–757 nm) for studies in photonics.
Collapse
Affiliation(s)
- Haoyu Jing
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Sijia Liu
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Jianbing Jiang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Vy-Phuong Tran
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Jie Rong
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Pengzhi Wang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Jonathan S. Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| |
Collapse
|
5
|
Yu Z, Uthe B, Gelfand R, Pelton M, Ptaszek M. Weakly conjugated bacteriochlorin-bacteriochlorin dyad: Synthesis and photophysical properties. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s1088424621500711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Dyads containing two near-infrared absorbing and emitting bacteriochlorins with distinct spectral properties have been prepared and characterized by absorption, emission, and transient-absorption spectroscopies. The dyads exhibit ultrafast ([Formula: see text]3 ps) energy transfer from the bacteriochlorin with the higher-energy S1 state to the bacteriochlorin emitting at the longer wavelength. The dyads exhibit strong fluorescence and relatively long excited state lifetimes ([Formula: see text]4 ns) in both non-polar and polar solvents, which indicates negligible photoinduced electron transfer between the two bacteriochlorins in the dyads. These dyads are thus attractive for the development of light-harvesting arrays and fluorophores for in vivo bioimaging.
Collapse
Affiliation(s)
- Zhanqian Yu
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Brian Uthe
- Department of Physics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Rachel Gelfand
- Department of Physics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Matthew Pelton
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
- Department of Physics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Marcin Ptaszek
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| |
Collapse
|
6
|
Aksu H, Maiti B, Ptaszek M, Dunietz BD. Photoinduced charge transfer in Zn(II) and Au(III)-ligated symmetric and asymmetric bacteriochlorin dyads: A computational study. J Chem Phys 2021; 153:134111. [PMID: 33032416 DOI: 10.1063/5.0023609] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The excited-state properties and photoinduced charge-transfer (CT) kinetics in a series of symmetrical and asymmetrical Zn- and Au-ligated meso-meso-connected bacteriochlorin (BChl) complexes are studied computationally. BChl derivatives, which are excellent near-IR absorbing chromophores, are found to play a central role in bacterial photosynthetic reaction centers but are rarely used in artificial solar energy harvesting systems. The optical properties of chemically linked BChl complexes can be tuned by varying the linking group and involving different ligated metal ions. We investigate charge transfer in BChl dyads that are either directly linked or through a phenylene ring (1,4-phenylene) and which are ligating Zn or Au ions. The directly linked dyads with a nearly perpendicular arrangement of the BChl units bear markedly different properties than phenylene linked dyads. In addition, we find that the dielectric dependence of the intramolecular CT rate is very strong in neutral Zn-ligated dyads, whereas cationic Au-ligated dyads show negligible dielectric dependence of the CT rate. Rate constants of the photo induced CT process are calculated at the semiclassical Marcus level and are compared to fully quantum mechanical Fermi's golden rule based values. The rates are calculated using a screened range separated hybrid functional that offers a consistent framework for addressing environment polarization. We study solvated systems in two solvents of a low and a high scalar dielectric constant.
Collapse
Affiliation(s)
- Huseyin Aksu
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, USA
| | - Buddhadev Maiti
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, USA
| | - Marcin Ptaszek
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore, Maryland 21250-1000, USA
| | - Barry D Dunietz
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, USA
| |
Collapse
|
7
|
Peymani S, Izadyar M, Arkan F. Photovoltaic and spectroscopic properties of bacteriochlorin-based photosensitizer: molecular approach. RESEARCH ON CHEMICAL INTERMEDIATES 2020. [DOI: 10.1007/s11164-020-04317-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
8
|
Aksu H, Schubert A, Bhandari S, Yamada A, Geva E, Dunietz BD. On the Role of the Special Pair in Photosystems as a Charge Transfer Rectifier. J Phys Chem B 2020; 124:1987-1994. [PMID: 32109062 DOI: 10.1021/acs.jpcb.9b11431] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The special pair, a bacteriochlorophyll a (BChl) dimer found at the core of bacterial reaction centers, is known to play a key role in the functionality of photosystems as a precursor to the photosynthesis process. In this paper, we analyze the inherent affinity of the special pair to rectify the intrapair photo-induced charge transfer (CT). In particular, we show that the molecular environment affects the nuclear geometry, resulting in symmetry breaking between the two possible intrapair CT processes. To this end, we study the relationships of the intrapair CT and the molecular geometry with respect to the effective dielectric constant provided by the molecular environment. We identify the special pair structural feature that breaks the symmetry between the two molecules, leading to CT rectification. Excited state energies, oscillator strengths, and electronic coupling values are obtained via time-dependent density functional theory, employing a recently developed framework based on a screened range-separated hybrid functional within a polarizable continuum model (SRSH-PCM). We analyze the rectification capability of the special pair by calculating the CT rates using a first-principles-based Fermi's golden rule approach.
Collapse
Affiliation(s)
- Huseyin Aksu
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Alexander Schubert
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States.,Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Srijana Bhandari
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Atsushi Yamada
- Center for Computational Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 Japan
| | - Eitan Geva
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Barry D Dunietz
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| |
Collapse
|
9
|
Aksu H, Schubert A, Geva E, Dunietz BD. Explaining Spectral Asymmetries and Excitonic Characters of the Core Pigment Pairs in the Bacterial Reaction Center Using a Screened Range-Separated Hybrid Functional. J Phys Chem B 2019; 123:8970-8975. [DOI: 10.1021/acs.jpcb.9b07646] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Huseyin Aksu
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Alexander Schubert
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Eitan Geva
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Barry D. Dunietz
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| |
Collapse
|
10
|
Meares A, Yu Z, Viswanathan Bhagavathy G, Satraitis A, Ptaszek M. Photoisomerization of Enediynyl Linker Leads to Slipped Cofacial Hydroporphyrin Dyads with Strong Through-Bond and Through-Space Electronic Interactions. J Org Chem 2019; 84:7851-7862. [PMID: 31117562 DOI: 10.1021/acs.joc.9b00731] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Photoisomerization of 3,4-di(methoxycarbonyl)-enediyne linker in hydroporphyrin (chlorin or bacteriochlorin) dyads leads to thermally stable cis isomers, where macrocycles adopt a slipped cofacial mutual geometry with an edge-to-edge distance of ∼3.6 Å (determined by density functional theory (DFT) calculations). Absorption spectra exhibit a significant splitting of the long-wavelength Qy band, which indicates a strong electronic coupling with a strength of V = ∼477 cm-1 that increases to 725 cm-1 upon metalation of hydroporphyrins. Each dyad features a broad, structureless emission band, with large Stokes shift, which is indicative of excimer formation. DFT calculations for dyads show both strong through-bond electronic coupling and through-space electronic interactions, due to the overlap of π-orbitals. Overall, geometry, electronic structure, strength of electronic interactions, and optical properties of reported dyads closely resemble those observed for photosynthetic special pairs. Dyads reported here represent a novel type of photoactive arrays with various modes of electronic interactions between chromophores. Combining through-bond and through-space coupling appears to be a viable strategy to engineer novel optical and photochemical properties in organic conjugated materials.
Collapse
Affiliation(s)
- Adam Meares
- Department of Chemistry and Biochemistry , University of Maryland, Baltimore County , 1000 Hilltop Circle , Baltimore , Maryland 21250 , United States
| | - Zhanqian Yu
- Department of Chemistry and Biochemistry , University of Maryland, Baltimore County , 1000 Hilltop Circle , Baltimore , Maryland 21250 , United States
| | - Ganga Viswanathan Bhagavathy
- Department of Chemistry and Biochemistry , University of Maryland, Baltimore County , 1000 Hilltop Circle , Baltimore , Maryland 21250 , United States
| | - Andrius Satraitis
- Department of Chemistry and Biochemistry , University of Maryland, Baltimore County , 1000 Hilltop Circle , Baltimore , Maryland 21250 , United States
| | - Marcin Ptaszek
- Department of Chemistry and Biochemistry , University of Maryland, Baltimore County , 1000 Hilltop Circle , Baltimore , Maryland 21250 , United States
| |
Collapse
|
11
|
Tiwari V, Matutes YA, Konar A, Yu Z, Ptaszek M, Bocian DF, Holten D, Kirmaier C, Ogilvie JP. Strongly coupled bacteriochlorin dyad studied using phase-modulated fluorescence-detected two-dimensional electronic spectroscopy. OPTICS EXPRESS 2018; 26:22327-22341. [PMID: 30130927 DOI: 10.1364/oe.26.022327] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/30/2018] [Indexed: 05/27/2023]
Abstract
Fluorescence-detected two-dimensional electronic spectroscopy (F-2DES) projects the third-order non-linear polarization in a system as an excited electronic state population which is incoherently detected as fluorescence. Multiple variants of F-2DES have been developed. Here, we report phase-modulated F-2DES measurements on a strongly coupled symmetric bacteriochlorin dyad, a relevant 'toy' model for photosynthetic energy and charge transfer. Coherence map analysis shows that the strongest frequency observed in the dyad is well-separated from the excited state electronic energy gap, and is consistent with a vibrational frequency readily observed in bacteriochlorin monomers. Kinetic rate maps show a picosecond relaxation timescale between the excited states of the dyad. To our knowledge this is the first demonstration of coherence and kinetic analysis using the phase-modulation approach to F-2DES.
Collapse
|