1
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Al-Owaedi OA. Thermoelectric Properties of Porphyrin Nano Rings: A Theoretical and Modelling Investigation. Chemphyschem 2024; 25:e202300616. [PMID: 38084460 DOI: 10.1002/cphc.202300616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/01/2023] [Indexed: 03/02/2024]
Abstract
Propagation of De Broglie waves through nanomolecular junctions is greatly affected by molecular topology changes, which in turn plays a key role in determining the electronic and thermoelectric properties of source|molecule|drain junctions. The probing and realization of the constructive quantum interference (CQI) and a destructive quantum interference (DQI) are well established in this work. The critical role of quantum interference (QI) in governing and enhancing the transmission coefficient T(E), thermopower (S), power factor (P) and electronic figure of merit (ZelT) of porphyrin nanorings has been investigated using a combination of density functional theory (DFT) methods, a tight binding (Hückel) modelling (TBHM) and quantum transport theory (QTT). Remarkably, DQI not only dominates the asymmetric molecular pathways and lowering T(E), but also improves the thermoelectric properties.
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Affiliation(s)
- Oday A Al-Owaedi
- Department of Laser Physics, University of Babylon, Babylon, Hilla, 51001, Iraq
- Al-Zahrawi University College, Holy Karbala, Karbala, 56001, Iraq
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2
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Erić V, Castro JL, Li X, Dsouza L, Frehan SK, Huijser A, Holzwarth AR, Buda F, Sevink GJA, de Groot HJM, Jansen TLC. Ultrafast Anisotropy Decay Reveals Structure and Energy Transfer in Supramolecular Aggregates. J Phys Chem B 2023; 127:7487-7496. [PMID: 37594912 PMCID: PMC10476209 DOI: 10.1021/acs.jpcb.3c04719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 07/20/2023] [Indexed: 08/20/2023]
Abstract
Chlorosomes from green bacteria perform the most efficient light capture and energy transfer, as observed among natural light-harvesting antennae. Hence, their unique functional properties inspire developments in artificial light-harvesting and molecular optoelectronics. We examine two distinct organizations of the molecular building blocks as proposed in the literature, demonstrating how these organizations alter light capture and energy transfer, which can serve as a mechanism that the bacteria utilize to adapt to changes in light conditions. Spectral simulations of polarization-resolved two-dimensional electronic spectra unravel how changes in the helicity of chlorosomal aggregates alter energy transfer. We show that ultrafast anisotropy decay presents a spectral signature that reveals contrasting energy pathways in different chlorosomes.
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Affiliation(s)
- Vesna Erić
- Zernike
Institute for Advanced Materials, University
of Groningen, 9747 AG Groningen, The Netherlands
| | - Jorge Luis Castro
- Zernike
Institute for Advanced Materials, University
of Groningen, 9747 AG Groningen, The Netherlands
| | - Xinmeng Li
- Department
of Chemistry and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, Sem Sælands vei 26, 0315 Oslo, Norway
| | - Lolita Dsouza
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Sean K. Frehan
- MESA+
Institute for Nanotechnology, University
of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands
| | - Annemarie Huijser
- MESA+
Institute for Nanotechnology, University
of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands
| | - Alfred R. Holzwarth
- Department
of Biophysical Chemistry, Max Planck Institute
for Chemical Energy Conversion, Stiftstraße 34-36, 45470 Mülheim, Germany
| | - Francesco Buda
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - G. J. Agur Sevink
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Huub J. M. de Groot
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, 2300 RA Leiden, The Netherlands
| | - Thomas L. C. Jansen
- Zernike
Institute for Advanced Materials, University
of Groningen, 9747 AG Groningen, The Netherlands
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3
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Kunsel T, Günther LM, Köhler J, Jansen TLC, Knoester J. Probing size variations of molecular aggregates inside chlorosomes using single-object spectroscopy. J Chem Phys 2021; 155:124310. [PMID: 34598584 DOI: 10.1063/5.0061529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We theoretically investigate the possibility to use single-object spectroscopy to probe size variations of the bacteriochlorophyll aggregates inside chlorosomes. Chlorosomes are the light-harvesting organelles of green sulfur and non-sulfur bacteria. They are known to be the most efficient light-harvesting systems in nature. Key to this efficiency is the organization of bacteriochlorophyll molecules in large self-assembled aggregates that define the secondary structure inside the chlorosomes. Many studies have been reported to elucidate the morphology of these aggregates and the molecular packing inside them. It is widely believed that tubular aggregates play an important role. Because the size (radius and length) of these aggregates affects the optical and excitation energy transport properties, it is of interest to be able to probe these quantities inside chlorosomes. We show that a combination of single-chlorosome linear polarization resolved spectroscopy and single-chlorosome circular dichroism spectroscopy may be used to access the typical size of the tubular aggregates within a chlorosome and, thus, probe possible variations between individual chlorosomes that may result, for instance, from different stages in growth or different growth conditions.
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Affiliation(s)
- T Kunsel
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - L M Günther
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, D-95440 Bayreuth, Germany
| | - J Köhler
- Spectroscopy of Soft Matter, University of Bayreuth, Universitätsstraße 30, D-95440 Bayreuth, Germany
| | - T L C Jansen
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - J Knoester
- University of Groningen, Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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4
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Günther LM, Löhner A, Reiher C, Kunsel T, Jansen TLC, Tank M, Bryant DA, Knoester J, Köhler J. Structural Variations in Chlorosomes from Wild-Type and a bchQR Mutant of Chlorobaculum tepidum Revealed by Single-Molecule Spectroscopy. J Phys Chem B 2018; 122:6712-6723. [PMID: 29863357 DOI: 10.1021/acs.jpcb.8b02875] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Green sulfur bacteria can grow photosynthetically by absorbing only a few photons per bacteriochlorophyll molecule per day. They contain chlorosomes, perhaps the most efficient light-harvesting antenna system found in photosynthetic organisms. Chlorosomes contain supramolecular structures comprising hundreds of thousands of bacteriochlorophyll molecules, which are properly positioned with respect to one another solely by self-assembly and not by using a protein scaffold as a template for directing the mutual arrangement of the monomers. These two features-high efficiency and self-assembly-have attracted considerable attention for developing light-harvesting systems for artificial photosynthesis. However, reflecting the heterogeneity of the natural system, detailed structural information at atomic resolution of the molecular aggregates is not yet available. Here, we compare the results for chlorosomes from the wild type and two mutants of Chlorobaculum tepidum obtained by polarization-resolved, single-particle fluorescence-excitation spectroscopy and theoretical modeling with results previously obtained from nuclear-magnetic resonance spectroscopy and cryo-electron microscopy. Only the combination of information obtained from all of these techniques allows for an unambiguous description of the molecular packing of bacteriochlorophylls within chlorosomes. In contrast to some suggestions in the literature, we find that, for the chlorosomes from the wild type as well as for those from mutants, the dominant secondary structural element features tubular symmetry following a very similar construction principle. Moreover, the results suggest that the various options for methylation of the bacteriochlorophyll molecules, which are a primary source of the structural (and spectral) heterogeneity of wild-type chlorosome samples, are exploited by nature to achieve improved spectral coverage at the level of individual chlorosomes.
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Affiliation(s)
| | | | | | - Tenzin Kunsel
- Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Thomas L C Jansen
- Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
| | - Marcus Tank
- Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , State College , Pennsylvania 16802 , United States
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , State College , Pennsylvania 16802 , United States.,Department of Chemistry and Biochemistry , Montana State University , Bozeman , Montana 59717 , United States
| | - Jasper Knoester
- Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 4 , 9747 AG Groningen , The Netherlands
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5
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Günther LM, Jendrny M, Bloemsma EA, Tank M, Oostergetel GT, Bryant DA, Knoester J, Köhler J. Structure of Light-Harvesting Aggregates in Individual Chlorosomes. J Phys Chem B 2016; 120:5367-76. [PMID: 27240572 DOI: 10.1021/acs.jpcb.6b03718] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Among all photosynthetic organisms, green bacteria have evolved one of the most efficient light-harvesting antenna, the chlorosome, that contains hundreds of thousands of bacteriochlorophyll molecules, allowing these bacteria to grow photosynthetically by absorbing only a few photons per bacteriochlorophyll molecule per day. In contrast to other photosynthetic light-harvesting antenna systems, for which a protein scaffold imposes the proper positioning of the chromophores with respect to each other, in chlorosomes, this is accomplished solely by self-assembly. This has aroused enormous interest in the structure-function relations of these assemblies, as they can serve as blueprints for artificial light harvesting systems. In spite of these efforts, conclusive structural information is not available yet, reflecting the sample heterogeneity inherent to the natural system. Here we combine mutagenesis, polarization-resolved single-particle fluorescence-excitation spectroscopy, cryo-electron microscopy, and theoretical modeling to study the chlorosomes of the green sulfur bacterium Chlorobaculum tepidum. We demonstrate that only the combination of these techniques yields unambiguous information on the structure of the bacteriochlorophyll aggregates within the chlorosomes. Moreover, we provide a quantitative estimate of the curvature variation of these aggregates that explains ongoing debates concerning the chlorosome structure.
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Affiliation(s)
- Lisa M Günther
- Experimental Physics IV, University of Bayreuth , D-95440 Bayreuth, Germany
| | - Marc Jendrny
- Experimental Physics IV, University of Bayreuth , D-95440 Bayreuth, Germany
| | - Erik A Bloemsma
- Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Marcus Tank
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Gert T Oostergetel
- Groningen Biomolecular Sciences and Biotechnology Institute , Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.,Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - Jasper Knoester
- Zernike Institute for Advanced Materials, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Jürgen Köhler
- Experimental Physics IV, University of Bayreuth , D-95440 Bayreuth, Germany
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6
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Jendrny M, Aartsma TJ, Köhler J. Insights into the excitonic states of individual chlorosomes from Chlorobaculum tepidum. Biophys J 2014; 106:1921-7. [PMID: 24806924 DOI: 10.1016/j.bpj.2014.03.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 02/26/2014] [Accepted: 03/14/2014] [Indexed: 11/16/2022] Open
Abstract
Green-sulfur bacteria have evolved a unique light-harvesting apparatus, the chlorosome, by which it is perfectly adapted to thrive photosynthetically under extremely low light conditions. We have used single-particle, optical spectroscopy to study the structure-function relationship of chlorosomes each of which incorporates hundreds of thousands of self-assembled bacteriochlorophyll (BChl) molecules. The electronically excited states of these molecular assemblies are described as Frenkel excitons whose photophysical properties depend crucially on the mutual arrangement of the pigments. The signature of these Frenkel excitons and its relation to the supramolecular organization of the chlorosome becomes accessible by optical spectroscopy. Because subtle spectral features get obscured by ensemble averaging, we have studied individual chlorosomes from wild-type Chlorobaculum tepidum by polarization-resolved fluorescence-excitation spectroscopy. This approach minimizes the inherent sample heterogeneity and allows us to reveal properties of the exciton states without ensemble averaging. The results are compared with predictions from computer simulations of various models of the supramolecular organization of the BChl monomers. We find that the photophysical properties of individual chlorosomes from wild-type Chlorobaculum tepidum are consistent with a (multiwall) helical arrangement of syn-anti stacked BChl molecules in cylinders and/or spirals of different size.
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Affiliation(s)
- Marc Jendrny
- Experimental Physics IV and Bayreuth Institute of Macromolecular Research (BIMF), Universität Bayreuth, Universitätsstr. 30, Bayreuth, Germany
| | - Thijs J Aartsma
- Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, Leiden, The Netherlands
| | - Jürgen Köhler
- Experimental Physics IV and Bayreuth Institute of Macromolecular Research (BIMF), Universität Bayreuth, Universitätsstr. 30, Bayreuth, Germany.
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7
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Arias DH, Stone KW, Vlaming SM, Walker BJ, Bawendi MG, Silbey RJ, Bulović V, Nelson KA. Thermally-Limited Exciton Delocalization in Superradiant Molecular Aggregates. J Phys Chem B 2012. [DOI: 10.1021/jp3086717] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Dylan H. Arias
- Department
of Chemistry and Center for Excitonics and ‡Research Laboratory of Electronics
and Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Katherine W. Stone
- Department
of Chemistry and Center for Excitonics and ‡Research Laboratory of Electronics
and Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Sebastiaan M. Vlaming
- Department
of Chemistry and Center for Excitonics and ‡Research Laboratory of Electronics
and Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Brian J. Walker
- Department
of Chemistry and Center for Excitonics and ‡Research Laboratory of Electronics
and Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Moungi G. Bawendi
- Department
of Chemistry and Center for Excitonics and ‡Research Laboratory of Electronics
and Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Robert J. Silbey
- Department
of Chemistry and Center for Excitonics and ‡Research Laboratory of Electronics
and Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Vladimir Bulović
- Department
of Chemistry and Center for Excitonics and ‡Research Laboratory of Electronics
and Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
| | - Keith A. Nelson
- Department
of Chemistry and Center for Excitonics and ‡Research Laboratory of Electronics
and Center for Excitonics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,
United States
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8
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Jendrny M, Aartsma TJ, Köhler J. Fluorescence Excitation Spectra from Individual Chlorosomes of the Green Sulfur Bacterium Chlorobaculum tepidum. J Phys Chem Lett 2012; 3:3745-3750. [PMID: 26291105 DOI: 10.1021/jz301808h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We performed polarization-resolved fluorescence excitation spectroscopy on individual chlorosomes from the photosynthetic green sulfur bacterium Chlorobaculum tepidum. The experiments were conducted at room temperature and under cryogenic conditions. All spectra showed a strong intensity modulation as a function of the polarization of the incident radiation, and we determined the modulation ratio as a function of the excitation energy. Under ambient conditions this ratio shows only little variation across the absorption band, whereas the low-temperature experiments clearly revealed that the broad absorption band around 740 nm consists of several spectral contributions.
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Affiliation(s)
- Marc Jendrny
- †Experimental Physics IV and Bayreuth Institute of Macromolecular Research (BIMF), Universität Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany
| | - Thijs J Aartsma
- ‡Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Jürgen Köhler
- †Experimental Physics IV and Bayreuth Institute of Macromolecular Research (BIMF), Universität Bayreuth, Universitätsstr. 30, 95447 Bayreuth, Germany
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9
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Vlaming SM, Bloemsma EA, Nietiadi ML, Knoester J. Disorder-induced exciton localization and violation of optical selection rules in supramolecular nanotubes. J Chem Phys 2011; 134:114507. [PMID: 21428632 DOI: 10.1063/1.3528993] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Using numerical simulations, we study the effect of disorder on the optical properties of cylindrical aggregates of molecules with strong excitation transfer interactions. The exciton states and the energy transport properties of such molecular nanotubes attract considerable interest for application in artificial light-harvesting systems and energy transport wires. In the absence of disorder, such nanotubes exhibit two optical absorption peaks, resulting from three super-radiant exciton states, one polarized along the axis of the cylinder, the other two (degenerate) polarized perpendicular to this axis. These selection rules, imposed by the cylindrical symmetry, break down in the presence of disorder in the molecular transition energies, due to the fact that the exciton states localize and no longer wrap completely around the tube. We show that the important parameter is the ratio of the exciton localization length and the tube's circumference. When this ratio decreases, the distribution of polarization angles of the exciton states changes from a two-peak structure (at zero and ninety degrees) to a single peak determined by the orientation of individual molecules within the tube. This is also reflected in a qualitative change of the absorption spectrum. The latter agrees with recent experimental findings.
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Affiliation(s)
- S M Vlaming
- Centre for Theoretical Physics and Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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10
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Schwartz E, Domingos SR, Vdovin A, Koepf M, Buma WJ, Cornelissen JJLM, Rowan AE, Nolte RJM, Woutersen S. Direct Access to Polyisocyanide Screw Sense Using Vibrational Circular Dichroism. Macromolecules 2010. [DOI: 10.1021/ma101601e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Erik Schwartz
- Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Sérgio R. Domingos
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Alexander Vdovin
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Matthieu Koepf
- Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Wybren Jan Buma
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Jeroen J. L. M. Cornelissen
- Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Alan E. Rowan
- Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Roeland J. M. Nolte
- Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Sander Woutersen
- Van ’t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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11
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Kuciauskas D, Caputo GA. Self-assembly of peptide-porphyrin complexes leads to pH-dependent excitonic coupling. J Phys Chem B 2010; 113:14439-47. [PMID: 19845410 DOI: 10.1021/jp905468y] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Using absorbance, fluorescence, resonance light scattering, and circular dichroism spectroscopy, we studied the self-assembly of the anionic meso-tetra(4-sulfonatophenyl)porphine (TPPS(4)(2-/4-)) and a cationic 22-residue polypeptide. We found that three TPPS(4)(2-/4-) molecules bind to the peptide, which contains nine lysine residues in the primary sequence. In acidic solutions, when the peptide is in the random-coil conformation, TPPS(4)(2-) bound to the peptide forms excitonically coupled J-aggregates. In pH 7.6 solutions, when the peptide secondary structure is partially alpha-helical, the porphyrin-to-peptide binding constants are approximately the same as in acidic solutions (approximately 3 x 10(6) M(-1)), but excitonic interactions between the porphyrins are insignificant. The binding of TPPS(4)(2-/4-) to lysine-containing peptides is cooperative and can be described by the Hill model. Our results show that porphyrin binding can be used to change the secondary structure of peptide-based biomaterials. In addition, binding to peptides could be used to optimize porphyrin intermolecular electronic interactions (exciton coupling), which is relevant for the design of light-harvesting antennas for artificial photosynthesis.
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Affiliation(s)
- Darius Kuciauskas
- Department of Chemistry and Biochemistry, Rowan University, 201 Mullica Hill Road, Glassboro, New Jersey 08028, USA.
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12
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Vlaming SM, Malyshev VA, Knoester J. Nonmonotonic energy harvesting efficiency in biased exciton chains. J Chem Phys 2007; 127:154719. [DOI: 10.1063/1.2784556] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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13
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Didraga C, Knoester J. Optical spectra and localization of excitons in inhomogeneous helical cylindrical aggregates. J Chem Phys 2006; 121:10687-98. [PMID: 15549954 DOI: 10.1063/1.1807825] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We study the linear optical properties of helical cylindrical molecular aggregates accounting for the effects of static diagonal disorder. Absorption, linear dichroism, and circular dichroism spectra are presented, calculated using brute force numerical simulations and a modified version of the coherent potential approximation that accounts for finite size effects by using the appropriate open boundary conditions. Excellent agreement between both approaches is found. It is also shown that the inclusion of disorder results in a better agreement between calculated and measured spectra for the chlorosomes of green bacteria as compared to our previous report, where we restricted ourselves to homogeneous cylinders [Didraga, Klugkist, and Knoester, J. Phys. Chem. B 106, 11474 (2002)]. For the excitons that govern the optical response, we also investigate the disorder-induced localization properties. By analyzing an autocorrelation function of the exciton wave function, we find a strongly anisotropic localization behavior, closely following the properties of chiral wave functions which previously have been found for homogenoeus helical cylinders [Didraga and Knoester, J. Chem. Phys. 121, 946 (2004)]. It is shown that the circular dichroism spectrum may still show a strong dependence on the cylinder length, even when the exciton wave function is localized in a region small compared to the cylinder's size.
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Affiliation(s)
- Cătălin Didraga
- Institute for Theoretical Physics and Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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14
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Pugzlys A, Augulis R, van Loosdrecht PHM, Didraga C, Malyshev VA, Knoester J. Temperature-Dependent Relaxation of Excitons in Tubular Molecular Aggregates: Fluorescence Decay and Stokes Shift. J Phys Chem B 2006; 110:20268-76. [PMID: 17034206 DOI: 10.1021/jp062983d] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report temperature-dependent steady-state and time-resolved fluorescence studies to probe the exciton dynamics in double-wall tubular J-aggregates formed by self-assembly of the dye 3,3'-bis(3-sulfopropyl)-5,5',6,6'-tetrachloro-1,1'-dioctylbenzimidacarbocyanine. We focus on the lowest energy fluorescence band, originating from the inner cylindrical wall. At low temperatures, the experiments reveal a nonexponential decay of the fluorescence, with a typical time scale that depends on the emission wavelength. At these temperatures we also find a dynamic Stokes shift of the fluorescence spectrum and its nonmonotonic dependence on temperature under steady-state conditions. All these data indicate that below about 20 K the excitons in the lowest fluorescence band do not reach thermal equilibrium before emission occurs, while above about 60 K thermalization on this time scale is complete. By comparing the two lowest fluorescence bands, we also find indications for fast energy transfer from the outer to the inner wall. We show that the Frenkel exciton model with diagonal disorder, which previously has been proposed to explain the absorption and linear dichroism spectra of these aggregates, yields a quantitative explanation to the observed dynamics. To this end, we extend the model to account for weak phonon-induced scattering of the localized exciton states; the spectral dynamics are then described by solving a Pauli master equation for the exciton populations.
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Affiliation(s)
- A Pugzlys
- Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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15
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Tomlinson A, Frezza B, Kofke M, Wang M, Armitage BA, Yaron D. A structural model for cyanine dyes templated into the minor groove of DNA. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Heijs DJ, Malyshev VA, Knoester J. Thermal broadening of the J-band in disordered linear molecular aggregates: A theoretical study. J Chem Phys 2005; 123:144507. [PMID: 16238407 DOI: 10.1063/1.2052591] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We theoretically study the temperature dependence of the J-band width in disordered linear molecular aggregates, caused by dephasing of the exciton states due to scattering on vibrations of the host matrix. In particular, we consider inelastic one- and two-phonon scatterings between different exciton states (energy-relaxation-induced dephasing), as well as the elastic two-phonon scattering of the excitons (pure dephasing). The exciton states follow from numerical diagonalization of a Frenkel exciton Hamiltonian with diagonal disorder; the scattering rates between them are obtained using the Fermi golden rule. A Debye-type model for the one- and two-phonon spectral densities is used in the calculations. We find that, owing to the disorder, the dephasing rates of the individual exciton states are distributed over a wide range of values. We also demonstrate that the dominant channel of two-phonon scattering is not the elastic one, as is often tacitly assumed, but rather comes from a similar two-phonon inelastic scattering process. In order to study the temperature dependence of the J-band width, we simulate the absorption spectrum, accounting for the dephasing-induced broadening of the exciton states. We find a power-law (T(p)) temperature scaling of the effective homogeneous width, with an exponent p that depends on the shape of the spectral density of the host vibrations. In particular, for a Debye model of vibrations, we find p approximately 4, which is in good agreement with the experimental data on J aggregates of pseudoisocyanine [I. Renge and U. P. Wild, J. Phys. Chem. A, 101, 7977 (1997)].
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Affiliation(s)
- D J Heijs
- Institute for Theoretical Physics and Materials Science Center, University of Groningen, The Netherlands
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Didraga C, Pugžlys A, Hania PR, von Berlepsch H, Duppen K, Knoester J. Structure, Spectroscopy, and Microscopic Model of Tubular Carbocyanine Dye Aggregates. J Phys Chem B 2004. [DOI: 10.1021/jp048288s] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cǎtǎlin Didraga
- Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Forschungszentrum für Elektronenmikroskopie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - Audrius Pugžlys
- Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Forschungszentrum für Elektronenmikroskopie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - P. Ralph Hania
- Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Forschungszentrum für Elektronenmikroskopie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - Hans von Berlepsch
- Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Forschungszentrum für Elektronenmikroskopie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - Koos Duppen
- Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Forschungszentrum für Elektronenmikroskopie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - Jasper Knoester
- Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and Forschungszentrum für Elektronenmikroskopie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
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