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Lebedeva MA, Chamberlain TW, Khlobystov AN. Harnessing the Synergistic and Complementary Properties of Fullerene and Transition-Metal Compounds for Nanomaterial Applications. Chem Rev 2015; 115:11301-51. [DOI: 10.1021/acs.chemrev.5b00005] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Maria A. Lebedeva
- School
of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | | | - Andrei N. Khlobystov
- School
of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Nottingham Nanotechnology & Nanoscience Centre, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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2
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Perchanova M, Kurreck H, Berg A. Time-Resolved Electron Paramagnetic Resonance Study of Photoinduced Electron Transfer in Pd Porphyrin–Quinone and Zn Porphyrin–Quinone Dyads with a Cyclohexylene Spacer. J Phys Chem A 2015; 119:8117-24. [DOI: 10.1021/acs.jpca.5b04760] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Maya Perchanova
- Institute
of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Harry Kurreck
- Institute of Chemistry and Biochemistry-Organic
Chemistry, Free University Berlin, Takustrasse 3, D-14195 Berlin, Germany
| | - Alexander Berg
- Institute
of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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3
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Schuster DI. Reflections on a Fifty-Year Career in Organic Photochemistry: A Personal Perspective. J Org Chem 2013; 78:6811-41. [DOI: 10.1021/jo4007078] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- David I. Schuster
- Department of Chemistry, New York University, New York, New York 10003, United States
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Ciammaichella A, Dral PO, Clark T, Tagliatesta P, Sekita M, Guldi DM. A π-stacked porphyrin-fullerene electron donor-acceptor conjugate that features a surprising frozen geometry. Chemistry 2012; 18:14008-16. [PMID: 23018982 DOI: 10.1002/chem.201202245] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Indexed: 11/06/2022]
Abstract
A "frozen" electron donor-acceptor array that bears porphyrin and fullerene units covalently linked through the ortho position of a phenyl ring and the nitrogen of a pyrrolidine ring, respectively, is reported. Electrochemical and photophysical features suggest that the chosen linkage supports both through-space and through-bond interactions. In particular, it has been found that the porphyrin singlet excited state decays within a few picoseconds by means of a photoinduced electron transfer to give the rapid formation of a long-lived charge-separated state. Density functional theory (DFT) calculations show HOMO and LUMO to be localized on the electron-donating porphyrin and the electron-accepting fullerene moiety, respectively, at this level of theory. More specifically, semiempirical molecular orbital (MO) configuration interaction (CI) and unrestricted natural orbital (UNO)-CI methods shed light on the nature of the charge-transfer states and emphasize the importance of the close proximity of donor and acceptor for effective electron transfer.
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Affiliation(s)
- Alina Ciammaichella
- Dipartimento di Scienze e Tecnologie Chimiche, University of Rome-Tor Vergata, Italy
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Abstract
In this review, porphyrins bearing quaternary azaaromatic moieties are described as follows: firstly those with useful physicochemical properties, then, species showing biological activities and finally, porphyrins bound with fullerenes and with cyclodextrins.
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Affiliation(s)
- Wanda Śliwa
- Institute of Chemistry and Environmental Protection, Jan Długosz University of Częstochowa, Armii Krajowej Ave 13/15, 42-201 Częstochowa, Poland
| | - Barbara Herman
- Institute of Chemistry and Environmental Protection, Jan Długosz University of Częstochowa, Armii Krajowej Ave 13/15, 42-201 Częstochowa, Poland
| | - Tomasz Girek
- Institute of Chemistry and Environmental Protection, Jan Długosz University of Częstochowa, Armii Krajowej Ave 13/15, 42-201 Częstochowa, Poland
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6
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Jakob M, Berg A, Levanon H, Schuster DI, Megiatto JD. Photoexcited state properties of H2-porphyrin/C60-based rotaxanes as studied by time-resolved electron paramagnetic resonance spectroscopy. J Phys Chem A 2011; 115:5044-52. [PMID: 21528881 DOI: 10.1021/jp202008j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Light-driven intramolecular electron transfer (ET) and energy transfer (EnT) processes in two rotaxanes, the first containing two free base porphyrins and C(60) fullerene moieties incorporated around a Cu(I)bisphenanthroline core ((H(2)P)(2)-Cu(I)(phen)(2)-C(60)) and a second lacking the fullerene moiety ((H(2)P)(2)-Cu(I)(phen)(2)), were studied by X-band (9.5 GHz) time-resolved electron paramagnetic resonance (TREPR) spectroscopy. The experiments were performed in frozen toluene and ethanol and different phases of the nematic liquid crystal (E-7). It is demonstrated that the ET and EnT processes in the (H(2)P)(2)-Cu(I)(phen)(2)-C(60) rotaxane in different media result in the formation of the same charge-separated state, namely (H(2)P)(2)(•+)-Cu(I)(phen)(2)(•-)-C(60), while photoexcitation of the (H(2)P)(2)-Cu(I)(phen)(2) rotaxane does not induce noticeable transfer processes in these matrices. The results are discussed in terms of the high conformational mobility of the rotaxanes, which enables changes in the molecular topography and resultant modification of the rates and routes of photoinduced processes occurring in these systems. The parameters of the transfer processes are compared with those obtained in our previous study of (ZnP)(2)-Cu(I)(phen)(2)-C(60) and (ZnP)(2)-Cu(I)(phen)(2) rotaxanes under the same experimental conditions.
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Affiliation(s)
- Manuela Jakob
- Institute of Chemistry, Hebrew University of Jerusalem, Jerusalem, Israel
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7
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Collini E, Fortunati I, Scolaro S, Signorini R, Ferrante C, Bozio R, Fabbrini G, Maggini M, Rossi E, Silvestrini S. A fullerene–distyrylbenzene photosensitizer for two-photon promoted singlet oxygen production. Phys Chem Chem Phys 2010; 12:4656-66. [DOI: 10.1039/b922740g] [Citation(s) in RCA: 9] [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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8
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Fazio M, Durandin A, Tkachenko N, Niemi M, Lemmetyinen H, Schuster D. Synthesis, Conformational Interconversion, and Photophysics of Tethered Porphyrin-Fullerene Dyads with Parachute Topology. Chemistry 2009; 15:7698-705. [DOI: 10.1002/chem.200900587] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Jakob M, Berg A, Rubin R, Levanon H, Li K, Schuster DI. Photoinduced Electron Transfer in Porphyrin- and Fullerene/Porphyrin-Based Rotaxanes as Studied by Time-Resolved EPR Spectroscopy. J Phys Chem A 2009; 113:5846-54. [DOI: 10.1021/jp900331j] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manuela Jakob
- Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904, Israel, and Department of Chemistry, New York University, New York, New York 10003
| | - Alexander Berg
- Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904, Israel, and Department of Chemistry, New York University, New York, New York 10003
| | - Roy Rubin
- Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904, Israel, and Department of Chemistry, New York University, New York, New York 10003
| | - Haim Levanon
- Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904, Israel, and Department of Chemistry, New York University, New York, New York 10003
| | - Ke Li
- Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904, Israel, and Department of Chemistry, New York University, New York, New York 10003
| | - David I. Schuster
- Department of Physical Chemistry, Hebrew University of Jerusalem, Jerusalem 91904, Israel, and Department of Chemistry, New York University, New York, New York 10003
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Lembo A, Tagliatesta P, Cicero D, Leoni A, Salvatori A. A glycyl-substituted porphyrin as a starting compound for the synthesis of a π–π-stacked porphyrin–fullerene dyad with a frozen geometry. Org Biomol Chem 2009; 7:1093-6. [DOI: 10.1039/b820501a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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11
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D'Souza F, Maligaspe E, Karr P, Schumacher A, El Ojaimi M, Gros C, Barbe JM, Ohkubo K, Fukuzumi S. Face-to-Face Pacman-Type Porphyrin–Fullerene Dyads: Design, Synthesis, Charge-Transfer Interactions, and Photophysical Studies. Chemistry 2008; 14:674-81. [DOI: 10.1002/chem.200700936] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Regev A, Galili T, Levanon H, Schuster DI. Triplet topology of self-assembled zinc porphyrin-pyridylfullerene complex. J Phys Chem A 2007; 110:8593-8. [PMID: 16821846 DOI: 10.1021/jp0613992] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This work extends a recent EPR study on light-driven electron and energy transfer in a self-assembled zinc porphyrin-pyridylfullerene (ZnP-PyrF) complex. We report on a triplet line shape analysis of the photoexcited PyrF monomer and the ZnP-PyrF complex dissolved in isotropic and anisotropic matrixes of different polarity, namely, toluene, tetrahydrofuran (THF), and the nematic liquid crystals (LCs), E-7 and ZLI-4389. The line shape of the unbound *(3)PyrF obtained in both isotropic matrixes exhibits triplet parameters similar to those obtained for other monoadducts of C(60) under similar experimental conditions. On the other hand, 8(3)PyrF oriented in the LCs shows a complicated line shape, which is attributed to two conformers: (a) an axial dominant (85%) configuration characterized by triplet parameters, similar to those obtained in the isotropic matrixes and (b) a bent configuration associated with spin density localized about the poles accompanied by sign reversal of the ZFS parameter D of the *(3)C(60) moiety. Further, since in both LCs the ZnP-PyrF complex mainly exhibits a conformation with axial symmetry, the differences between the electron and the energy transfer routes in each LC are attributed to their different polarity. This study reflects the strength of LC matrixes to serve as a topological tool, enabling us to determine the conformers' distribution and to differentiate between electron and energy transfer routes.
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Affiliation(s)
- Ayelet Regev
- Department of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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13
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Liao MS, Watts JD, Huang MJ. Interaction of Metal Porphyrins with Fullerene C60: A New Insight. J Phys Chem B 2007; 111:4374-82. [PMID: 17417891 DOI: 10.1021/jp064367n] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The electronic structure and bonding in the noncovalent, supramolecular complexes of fullerene C60 with a series of first-row transition metal porphines MP (M=Fe, Co, Ni, Cu, Zn) have been re-examined with DFT methods. A dispersion correction was made for the C60-MP binding energy through an empirical method (J. Comput. Chem. 2004, 25, 1463). Several density functionals and two types of basis sets were employed in the calculations. Our calculated results are rather different from those obtained in a recent paper (J. Phys. Chem. A 2005, 109, 3704). The ground state of C60.FeP is predicted to be high spin (S=2); the low-spin (S=0), closed-shell state is even higher in energy than the intermediate-spin (S=1) state. With only one electron in the Co-dz2 orbital, the calculated Co-C60 distance is in fact rather short, about 0.1 A longer than the Fe-C60 distance in high-spin C60.FeP. Double occupation of an M-dz2 orbital in MP prevents close association of any axial ligand, and so the Ni-C60, Cu-C60, and Zn-C60 distances are much longer than the Co-C60 one. The evaluated MP-C60 binding energies (Ebind) are 0.8 eV (18.5 kcal/mol) for M=Fe/Co and 0.5 eV (11.5 kcal/mol) for M=Ni/Cu/Zn (Ebind is about 0.2 eV larger in the case of C60-MTPP). They are believed to be reliable and accurate based on our dispersion-corrected DFT calculations that included the counterpoise (CP) correction. The effects of the C60 contact on the redox properties of MP were also examined.
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Affiliation(s)
- Meng-Sheng Liao
- Department of Chemistry, P.O. Box 17910, Jackson State University, Jackson, Mississippi 39217, USA
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14
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Moribe S, Yonemura H, Yamada S. Magnetic field effects and time-resolved EPR studies on the photogenerated biradicals in phenothiazine–C60 linked systems: Clarification of the mechanism of novel magnetic field effects by dependences of methylene chain length and temperature. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Bhattacharya S, Tominaga K, Kimura T, Uno H, Komatsu N. A new metalloporphyrin dimer: Effective and selective molecular tweezers for fullerenes. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2006.11.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Vuorinen T, Kaunisto K, Chukharev V, Tkachenko NV, Efimov A, Lemmetyinen H. Kinetics of Photoinduced Electron Transfer in Polythiophene−Porphyrin−Fullerene Molecular Films. J Phys Chem B 2006; 110:19515-20. [PMID: 17004813 DOI: 10.1021/jp063076b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Photoinduced electron transfer (ET) processes were studied by the time-resolved Maxwell displacement charge (TRMDC) method in bilayer structures consisting of an electron donor-acceptor and conductive polymer monolayers, porphyrin-fullerene dyad and polyhexylthiophene, respectively, both layers prepared by the Langmuir-Blodgett (LB) method. The charge separation involves two fast steps: an intramolecular ET in the dyad molecule followed by an interlayer ET from the polymer to the formed porphyrin radical cation. These fast vertical intra- and interlayer processes could not be time-resolved by the TRMDC method. The lifetime of the charge separated state in the system was extended to hundreds of milliseconds by lateral electron and hole transfers in fullerene and polymer sublayers. The kinetics of the system was described by a model involving two long-living energetically different complete charge separated states. The data analysis indicates that the charge separation has a recombination time of 0.5 s. This is a promising result for possible applications.
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Affiliation(s)
- Tommi Vuorinen
- Institute of Materials Chemistry, Tampere University of Technology, P.O. Box 541, FIN-33101 Tampere, Finland.
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17
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Allen BD, Benniston AC, Harriman A, Mallon LJ, Pariani C. Competing through-space and through-bond, intramolecular triplet-energy transfer in a supposedly rigid ruthenium(II) tris(2,2'-bipyridine)--fullerene molecular dyad. Phys Chem Chem Phys 2006; 8:4112-8. [PMID: 17028700 DOI: 10.1039/b609080j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A ditopic ruthenium(II) tris(2,2'-bipyridyl)-based fullerene conjugate has been synthesized so as to separate the photoactive terminals by way of a short ethynylene spacer group that is expected to act as a rigid rod. Intramolecular triplet-energy transfer from the metal complex to the fullerene is quantitative at all temperatures and there is no indication for competing electron transfer. Temperature dependence studies indicate two pathways for triplet-energy transfer. An activationless route dominates at low temperature and is attributed to through-bond electron exchange that takes place via super-exchange interactions. The triplet energy of the bridging unit lies well above that of the metal complex. An activated process is switched-on at high temperatures and is believed to involve through-space electron exchange within closed conformations. Molecular dynamics simulations predict that, in addition to an extended conformation, the linker can distort in such a way that the terminals come into orbital contact. In fact, the resultant closed conformation possesses an idealised geometry for fast electron exchange.
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Affiliation(s)
- Ben D Allen
- Molecular Photonics Laboratory, School of Natural Sciences, University of Newcastle, Newcastle upon Tyne, UK NE1 7RU
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19
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Kapko V, Matyushov DV. Dynamical Arrest of Electron Transfer in Liquid Crystalline Solvents. J Phys Chem B 2006; 110:13184-94. [PMID: 16805631 DOI: 10.1021/jp0615205] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We argue that electron transfer reactions in slowly relaxing solvents proceed in the nonergodic regime, making the reaction activation barrier strongly dependent on the solvent dynamics. For typical dielectric relaxation times of polar nematics, electron transfer reactions in the subnanosecond time scale fall into nonergodic regime in which nuclear solvation energies entering the activation barrier are significantly lower than their thermodynamic values. The transition from isotropic to nematic phase results in weak discontinuities of the solvation energies at the transition point and the appearance of solvation anisotropy weakening with increasing solute size. The theory is applied to analyze experimental kinetic data for the electron transfer kinetics in the isotropic phase of 5CB liquid crystalline solvent. We predict that the energy gap law of electron transfer reactions in slowly relaxing solvents is characterized by regions of fast change of the rate at points where the reaction switches between the ergodic and nonergodic regimes. The dependence of the rate on the donor-acceptor separation may also be affected in a way of producing low values for the exponential falloff parameter.
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Affiliation(s)
- Vitaliy Kapko
- Department of Chemistry and Biochemistry and the Center for the Early Events in Photosynthesis, Arizona State University, P.O. Box 871604, Tempe, Arizona 85287-1604, USA
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Guldi DM, Rahman GMA, Sgobba V, Ehli C. Multifunctional molecular carbon materials--from fullerenes to carbon nanotubes. Chem Soc Rev 2006; 35:471-87. [PMID: 16636729 DOI: 10.1039/b511541h] [Citation(s) in RCA: 360] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This critical review covers the timely topic of carbon nanostructures-fullerenes and carbon nanotubes-in combination with metalloporphyrins as integrative components for electron-donor-acceptor ensembles. These ensembles are typically probed in condensed media and at semi-transparent electrode surfaces. In particular, we will present a comprehensive survey of a variety of covalent (i.e., nanoconjugates) and non-covalent linkages (i.e., nanohybrids) to demonstrate how to govern/fine-tune the electronic interactions in the resulting electron-donor-acceptor ensembles. In the context of covalent bridges, different spacers will be discussed, which range from pure "insulators" (i.e., amide bonds, etc.) to sophisticated "molecular wires" (i.e., p-phenylenevinylene units, etc.). Furthermore, we will elucidate the fundamental impact that these vastly different spacers may exert on the rate, efficiency, and mechanism of short- and long-range electron transfer reactions. Additionally, a series of non-covalent motifs will be described: hydrogen bonding, complementary electrostatics, pi-pi stacking and metal coordination-to name a few. These motifs have been successfully employed by us and our collaborators en route towards novel architectures (i.e., linear structures, tubular structures, rotaxanes, catenanes, etc.) that exhibit unique and remarkable charge transfer features.
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Affiliation(s)
- Dirk M Guldi
- Universität Erlangen, Institute for Physical and Theoretical Chemistry, 91058 Erlangen, Germany
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21
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Vuorinen T, Kaunisto K, Tkachenko NV, Efimov A, Lemmetyinen H. Photoinduced interlayer electron transfer in alternating porphyrin–fullerene dyad and regioregular poly(3-hexylthiophene) Langmuir–Blodgett films. J Photochem Photobiol A Chem 2006. [DOI: 10.1016/j.jphotochem.2005.10.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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22
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Schuster DI, MacMahon S, Guldi DM, Echegoyen L, Braslavsky SE. Synthesis and photophysics of porphyrin–fullerene donor–acceptor dyads with conformationally flexible linkers. Tetrahedron 2006. [DOI: 10.1016/j.tet.2005.07.127] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Bortolus M, Ferrarini A, van Tol J, Maniero AL. Full Determination of Zero Field Splitting Tensor of the Excited Triplet State of C60 Derivatives of Arbitrary Symmetry from High Field TREPR in Liquid Crystals. J Phys Chem B 2006; 110:3220-4. [PMID: 16494332 DOI: 10.1021/jp056223z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The low-lying photoexcited triplet state of a series of fullerene C(60) adducts has been studied by high-field TREPR (time-resolved EPR) spectroscopy in a partially oriented phase. The fullerenes adopt a biaxial alignment, driven by the substituents, that has allowed to fully determine the ZFS and g tensors, i.e., their principal values and the orientation of the principal axes in the molecular skeleton. This has been accomplished by combining line shape analysis and theoretical prediction of molecular order. A strong dependence of the magnetic tensors on the substitution pattern has been found.
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Affiliation(s)
- Marco Bortolus
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, I-35131 Padova, Italy
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Sandanayaka ASD, Taguri Y, Araki Y, Ishi-I T, Mataka S, Ito O. Photoinduced Charge Separation and Charge Recombination in the [60]Fullerene−Diphenylbenzothiadiazole−Triphenylamine Triad: Role of Diphenylbenzothiadiazole as Bridge. J Phys Chem B 2005; 109:22502-12. [PMID: 16853931 DOI: 10.1021/jp053809c] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photoinduced electron-transfer processes of the newly synthesized [60]fullerene-diphenylbenzothiadiazole-triphenylamine (C60-PBTDP-TPA) triad in polar and nonpolar solvents have been studied by using time-resolved transient absorption and fluorescence measurements from picosecond to microsecond regions. By fluorescence lifetime measurements in picosecond time regions, excitation of the charge-transfer transition of the PBTDP-TPA moiety in C60-PBTDP-TPA induces energy transfer to the C60 moiety generating 1C60*-PBTDP-TPA, competitively with charge separation generating C60*--PBTDP-TPA*+. From 1C60*-PBTDP-TPA, which is generated directly and indirectly, charge separation occurs generating C60*--PBTDP-TPA*+ in polar solvents. The C60*--PBTDP-TPA*+ formed via the singlet excited states decayed within a few nanoseconds as revealed by the picosecond transient absorption spectra. In the nanosecond time region, C60*--PBTDP-TPA*+ is produced slowly, probably via 3C60*-PBTDP-TPA. Lifetimes of such slowly generated C60*--PBTDP-TPA*+ were longer than 1 micros, which are the longest values among the C60-bridge-TPA triad systems reported hitherto at room temperature. Roles of the PBTDP-TPA moiety with twisted intermolecular charge-transfer character playing as energy donor and electron donor in addition to the bridge have been disclosed.
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Affiliation(s)
- Atula S D Sandanayaka
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
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Galili T, Regev A, Berg A, Levanon H, Schuster DI, Möbius K, Savitsky A. Intramolecular Electron and Energy Transfer in an Axial ZnP−Pyridylfullerene Complex As Studied by X- and W-Band Time-Resolved EPR Spectroscopy. J Phys Chem A 2005; 109:8451-8. [PMID: 16834241 DOI: 10.1021/jp052873r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Light-driven electron transfer (ET) and energy transfer (EnT) in a self-assembled via axial coordination Zn-porphyrin-pyridylfullerene (ZnP-PyrF) complex were studied by time-resolved electron paramagnetic resonance (TREPR) spectroscopy at 9.5 GHz (X-band) and 95 GHz (W-band). The studies over a wide temperature range were carried out in media of different polarity, including isotropic toluene and tetrahydrofuran (THF), and anisotropic nematic liquid crystals (LCs), E-7 and ZLI-4389. At low temperatures (frozen matrices), photoexcitation of the ZnP donor results mainly in singlet-singlet EnT to the pyridine-appended fullerene acceptor. In fluid phases ET is the dominant process. Specifically, in isotropic solvents the generated radical pairs (RPs) are long-lived, with lifetimes exceeding that observed for covalently linked donor-acceptor systems. It is concluded that in liquid phases of both polar and nonpolar solvents the separation of the tightly bound complex into the more loosely bound structure slows down the back ET (BET) process. Photoexcitation of the donor in fluid phases of LCs does not result in the creation of the long-lived RPs, since the ordered LC matrix hinders the separation of the complex constituents. As a result, fast intramolecular BET takes place in the tightly bound complex. Contrarily to the behavior of covalently linked donor-acceptor systems in different LCs, the polarity of the LC matrix affects the ET process. Moreover, in contrast to covalently linked D-s-A systems, utilization of LCs for the coordinatively linked D-s-A complexes does not reduce the ET rates significantly.
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Affiliation(s)
- Tamar Galili
- Department of Physical Chemistry and the Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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