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Daisymol KB, Gopidas KR. Thousand-Fold Enhancement of Charge-Separated State Lifetimes Caused by an Adamantane Bridge in Dimethylaniline-Anthracene and Dimethylaniline-Pyrene Dyads. J Phys Chem Lett 2023; 14:977-982. [PMID: 36692390 DOI: 10.1021/acs.jpclett.2c03453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
A long-standing challenge in photoinduced electron transfer research is the design of compact donor-acceptor dyads that can generate long-lived charge-separated (CS) states for use as sensitizers in solar energy harvesting. Reports of dyads exhibiting CS state lifetimes in the microsecond time domain are very rare. Herein, we report two compact donor-bridge-acceptor dyads exhibiting lifetimes in the microsecond domain. We employed an adamantane moiety as a bridge, and the lifetimes obtained are nearly 1000-fold larger when compared to those of the same donor-acceptor dyads bridged through C3-alkyl chains. In addition to long-lived CS state decays, slow formation of acceptor triplets was also observed via nanosecond flash photolysis. The long lifetime of the CS state is attributed to the extremely small value of the electronic coupling matrix element for the charge recombination compared to charge separation.
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Affiliation(s)
- Kurisingal B Daisymol
- Photosciences and Photonics, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Karical R Gopidas
- Photosciences and Photonics, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
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Glaser F, Kerzig C, Wenger OS. Sensitization-initiated electron transfer via upconversion: mechanism and photocatalytic applications. Chem Sci 2021; 12:9922-9933. [PMID: 34349964 PMCID: PMC8317647 DOI: 10.1039/d1sc02085d] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/16/2021] [Indexed: 12/12/2022] Open
Abstract
Sensitization-initiated electron transfer (SenI-ET) describes a recently discovered photoredox strategy that relies on two consecutive light absorption events, triggering a sequence of energy and electron transfer steps. The cumulative energy input from two visible photons gives access to thermodynamically demanding reactions, which would be unattainable by single excitation with visible light. For this reason, SenI-ET has become a very useful strategy in synthetic photochemistry, but the mechanism has been difficult to clarify due to its complexity. We demonstrate that SenI-ET can operate via sensitized triplet-triplet annihilation upconversion, and we provide the first direct spectroscopic evidence for the catalytically active species. In our system comprised of fac-[Ir(ppy)3] as a light absorber, 2,7-di-tert-butylpyrene as an annihilator, and N,N-dimethylaniline as a sacrificial reductant, all photochemical reaction steps proceed with remarkable rates and efficiencies, and this system is furthermore suitable for photocatalytic aryl dehalogenations, pinacol couplings and detosylation reactions. The insights presented here are relevant for the further rational development of photoredox processes based on multi-photon excitation, and they could have important implications in the greater contexts of synthetic photochemistry and solar energy conversion.
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Affiliation(s)
- Felix Glaser
- Department of Chemistry, University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Christoph Kerzig
- Department of Chemistry, University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel St. Johanns-Ring 19 4056 Basel Switzerland
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3
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Eremenko A. Photoinduced intermolecular charge transfer processes on pure and modified silica surfaces. RESEARCH ON CHEMICAL INTERMEDIATES 2019. [DOI: 10.1007/s11164-019-03886-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Preface. RESEARCH ON CHEMICAL INTERMEDIATES 2019. [DOI: 10.1007/s11164-019-03883-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Vancea A, Kirkpatrick I, Worrall DR, Williams SL. Energy and electron transfer reactions on silica gel and titania–silica mixed oxide surfaces. RESEARCH ON CHEMICAL INTERMEDIATES 2019. [DOI: 10.1007/s11164-019-03901-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Kirkpatrick I, Worrall DR, Williams SL, Buck CJT, Meseguer RG. Probing the interplay between factors determining reaction rates on silica gel using termolecular systems. Photochem Photobiol Sci 2012; 11:1585-91. [PMID: 22898878 DOI: 10.1039/c2pp25171j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study we have compared energy and electron transfer reactions in termolecular systems using a nanosecond diffuse reflectance laser flash photolysis technique. We have previously investigated these processes on silica gel surfaces for bimolecular systems and electron transfer in termolecular systems. The latter systems involved electron transfer between three arene molecules with azulene acting as a molecular shuttle. In this study we present an alternative electron transfer system using trans β-carotene as an electron donor in order to effectively immobilise all species except the shuttle, providing the first unambiguous evidence for radical ion mobility. In the energy transfer system we use naphthalene, a structural isomer of azulene, as the shuttle, facilitating energy transfer from a selectively excited benzophenone sensitiser to 9-cyanoanthracene. Bimolecular rate constants for all of these processes have been measured and new insights into the factors determining the rates of these reactions on silica gel have been obtained.
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Affiliation(s)
- Iain Kirkpatrick
- Department of Chemistry, Loughborough University, Loughborough, Leicestershire LE11 3TU, UK
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Gujrati MD, Kumar NSS, Brown AS, Captain B, Wilson JN. Luminescent charge-transfer complexes: tuning emission in binary fluorophore mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:6554-8. [PMID: 21548624 DOI: 10.1021/la2012809] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Charge-transfer (CT) complexes composed of a π-electron-poor naphthalene diimide (NDI) derivative combined with a series of π-electron-rich donors were investigated. Solutions of the CT complexes are nonemissive; however, solid-state complexes and aqueous suspensions display emission that is dependent on the energy of the HOMO of the electron donor. Crystallographic analysis of a pyrene-NDI complex reveals columnar packing and a high degree of frontier molecular orbital (FMO) overlap that likely contributes to the observed optical properties. The fluorescent CT particles are utilized as imaging agents; additional luminescent CT complexes may be realized by considering FMO energies and topologies.
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Affiliation(s)
- Maneesh D Gujrati
- Center for Supramolecular Science and Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33124, United States
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Banerjee A, Karak D, Sahana A, Guha S, Lohar S, Das D. Methionine-pyrene hybrid based fluorescent probe for trace level detection and estimation of Hg(II) in aqueous environmental samples: experimental and computational studies. JOURNAL OF HAZARDOUS MATERIALS 2011; 186:738-744. [PMID: 21146291 DOI: 10.1016/j.jhazmat.2010.11.060] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 11/11/2010] [Accepted: 11/15/2010] [Indexed: 05/30/2023]
Abstract
A new fluorescent, Hg(2+) selective chemosensor, 4-methylsulfanyl-2-[(pyren-4-ylmethylene)-amino] butyric acid methyl ester (L, MP) was synthesized by blending methionine with pyrene. It was well characterized by different analytical techniques, viz. (1)H NMR, (13)C NMR, QTOF mass spectra, elemental analysis, FTIR and UV-vis spectroscopy. The reaction of this ligand with Hg(2+) was studied by steady state and time-resolved fluorescence spectroscopy. The Hg(2+) complexation process was confirmed by comparing FTIR, UV-vis, thermal, QTOF mass spectra and (1)H NMR data of the product with that of the free ligand values. The composition (Hg(2+):L=1:1) of the Hg(2+) complex in solution was evaluated by fluorescence titration method. Based on the chelation assisted fluorescence quenching, a highly sensitive spectrofluorometric method was developed for the determination of trace amounts of Hg(2+) in water. The ligand had an excitation and emission maxima at 360 nm and 455 nm, respectively. The fluorescence life times of the ligand and its Hg(2+) complex were 1.54 ns and 0.72 ns respectively. The binding constant of the ligand, L with Hg(2+) was calculated using Benesi-Hildebrand equation and was found to be 7.5630×10(4). The linear range of the method was from 0 to 16 μg L(-1) with a detection limit of 0.056 μg L(-1) for Hg(2+). The quantum yields of the ligand and its Hg(2+) complex were found to be 0.1206 and 0.0757 respectively. Both the ligand and its Hg(2+) complex have been studied computationally (Ab-initio, Hartree Fock method) to get their optimized structure and other related physical parameters, including bond lengths, bond angles, dipole moments, orbital interactions etc. The binding sites of the ligand to the Hg(2+) ion as obtained from the theoretical calculations were well supported by (1)H NMR titration. The interference of foreign ions was negligible. This method has been successfully applied to the determination of mercury(II) in industrial waste water.
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Affiliation(s)
- Arnab Banerjee
- Department of Chemistry, The University of Burdwan, Golapbag, Burdwan, West Bengal, India
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Williams SL, Worrall DR, Kirkpatrick I, Vancea A, Pan J. Activation energies of photoinduced unimolecular, bimolecular and termolecular processes on silica gel surfaces. Photochem Photobiol Sci 2010; 10:84-90. [PMID: 20978659 DOI: 10.1039/c0pp00256a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Activation energies for energy and electron transfer have been measured in various systems on silica gel. In the case of ion-electron recombination, a facile technique involving fluorescence recovery is described which complements diffuse reflectance spectroscopy in the study of these systems. In bimolecular anthracene/azulene systems, activation energies have been shown to be independent of pre-treatment temperature in the range 25-210 °C, demonstrating that physisorbed water plays little role in determining diffusion rates on silica gel. In a ternary anthracene/azulene/perylene system, we have for the first time presented comparative activation energies for the diffusion of azulene and its radical cation, and have shown a greater activation energy for diffusion of the latter species.
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Affiliation(s)
- Siân L Williams
- Department of Chemistry, Loughborough University, Loughborough, Leicestershire, UK LE11 3TU.
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Williams SL, Kirkpatrick I, Worrall DR. Electron transfer reactions in ternary systems on silica gel surfaces: evidence for radical cation diffusion. Photochem Photobiol Sci 2010; 9:937-41. [DOI: 10.1039/c0pp00049c] [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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11
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Lee DK, Cha HG, Pal U, Kang YS. Kinetics of Decolorization of Spironaphthooxazine-Doped Photochromic Polymer Films. J Phys Chem B 2009; 113:12923-7. [DOI: 10.1021/jp905700s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Don Keun Lee
- Cheil Industries Inc. Pyeongyeo-Dong, Yeosu-si, Jeollanam-do 555-210, Republic of Korea, and Department of Chemistry, Sogang University, Shinsu-dong, Seoul 121-742, Republic of Korea
| | - Hyun Gil Cha
- Cheil Industries Inc. Pyeongyeo-Dong, Yeosu-si, Jeollanam-do 555-210, Republic of Korea, and Department of Chemistry, Sogang University, Shinsu-dong, Seoul 121-742, Republic of Korea
| | - Umapada Pal
- Cheil Industries Inc. Pyeongyeo-Dong, Yeosu-si, Jeollanam-do 555-210, Republic of Korea, and Department of Chemistry, Sogang University, Shinsu-dong, Seoul 121-742, Republic of Korea
| | - Young Soo Kang
- Cheil Industries Inc. Pyeongyeo-Dong, Yeosu-si, Jeollanam-do 555-210, Republic of Korea, and Department of Chemistry, Sogang University, Shinsu-dong, Seoul 121-742, Republic of Korea
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Metal Ion Enhanced Charge Transfer in a Terpyridine-bis-Pyrene System. SENSORS 2009; 9:3604-26. [PMID: 22412328 PMCID: PMC3297157 DOI: 10.3390/s90503604] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 05/08/2009] [Accepted: 05/12/2009] [Indexed: 11/16/2022]
Abstract
The synthesis, electrochemical and photophysical properties of a branched molecule 3,5-bis(pyrene-1-yl)-4'-phenyl-2,2':6',2″-terpyridine are reported. Spectroscopy in different solvents reveals that an optical electron transfer from the pyrene donor to the terpyridyl electron acceptor can occur in polar media, as the system displays both charge transfer (CT) absorption and CT emission. Furthermore, the study of the zinc complex as well as the bis-protonated form shows an enhancement of the electron transfer character of the system, by an increase of the acceptor strength. This is accompanied by a large increase of the non-radiative processes. With sub-nanosecond transient absorption spectroscopy, the CT state, consisting of the pyrene radical cation and the terpyridine radical anion, has been detected. At room temperature, the study of the nanosecond transient absorption spectra reveals the formation of a low-lying triplet excited state that we attribute to the pyrene moiety through which the CT state decays. At 77K, the absence of the terpyridine triplet emission also suggests the population of a low-lying triplet state of the pyrene unit.
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Shen F, Peng A, Chen Y, Dong Y, Jiang Z, Wang Y, Fu H, Yao J. Photoinduced Electron Transfer in Coaggregates of Dicyanonaphthalene and Pyrazoline. J Phys Chem A 2008; 112:2206-10. [DOI: 10.1021/jp076207x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Fugang Shen
- Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China, and Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
| | - Aidong Peng
- Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China, and Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
| | - Yu Chen
- Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China, and Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
| | - Yang Dong
- Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China, and Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
| | - Ziwen Jiang
- Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China, and Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
| | - Yaobing Wang
- Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China, and Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
| | - Hongbing Fu
- Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China, and Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
| | - Jiannian Yao
- Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P.R. China, and Graduate School, Chinese Academy of Sciences, Beijing 100039, P.R. China
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Li YY, Han L, Chen J, Zheng S, Zen Y, Li Y, Li S, Yang G. Study on the Extent of Folding Back Conformation in Poly(aryl ether) Dendrimers by Intramolecular Electron Transfer and Exciplex Formation. Macromolecules 2007. [DOI: 10.1021/ma071901w] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Branco TJF, Vieira Ferreira LF, Botelho do Rego AM, Oliveira AS, Da Silva JP. Pyrene–p-tert-butylcalixarenes inclusion complexes formation: a surface photochemistry study. Photochem Photobiol Sci 2006; 5:1068-77. [PMID: 17077904 DOI: 10.1039/b608833c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Diffuse reflectance and luminescence techniques were used to study the photophysics and photochemistry of pyrene within p-tert-butylcalix[n]arenes with n = 4, 6, and 8, and to study their ability to form inclusion complexes in heterogeneous media. Evidences for inclusion complex formation were found for the three hosts under study. Ground state diffuse reflectance results have shown the formation of ground state dimers of pyrene inside the cavity of calix[6]arene and calix[8]arene, with this feature much more evident for calix[6]arene. For calix[4]arene, only a monomer fits inside the cavity and the presence of pyrene microcrystals outside the cavity was detected. A luminescence lifetime distribution analysis was performed, revealing the presence of prompt emissions from the pyrene microcrystals outside the cavity in the case of calix[4]arene and from the constrained dimers inside the cavities of calix[6]arene and calix[8]arene. Transient absorption results have shown the presence of pyrene radical cation and also of trapped electrons for the three hosts under study. The formation of the phenoxyl radical of the calixarene following the laser pulsed excitation of pyrene at 355 nm is increased for calix[6]arene and calix[8]arene. This feature is particularly relevant for calix[6]arene, suggesting a very favourable situation for the hydrogen atom abstraction to occur. The analysis of the degradation products revealed the presence of hydroxypyrene as a major photodegradation product for the three hosts. Dihydro-hydroxypyrene was also formed in the case of calix[6]arene and calix[8]arene. The formation of the calixarene's phenoxyl radical and subsequent hydrogen abstraction is consistent with the formation of dihydro-dihydroxypyrene.
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Affiliation(s)
- T J F Branco
- Centro de Química-Física Molecular, Instituto Superior Técnico, 1049-001, Lisboa, Portugal
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Photophysical properties of TICT molecule adsorbed on semiconductor titania–silica colloids. J Photochem Photobiol A Chem 2006. [DOI: 10.1016/j.jphotochem.2005.05.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Worrall DR, Williams SL, Ganguly T. Ion–electron recombination on silica gel surfaces: experiment and modelling. Photochem Photobiol Sci 2006; 5:844-9. [PMID: 17047837 DOI: 10.1039/b608601b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Kinetics on silica gel and other solid, porous surfaces are often complex. In this paper we have studied the decay kinetics of radical cations produced following multiphoton ionisation on silica gel, and have characterised these using an empirical model. Trends in kinetics have been observed both as a function of concentration and of temperature. Concentration dependent studies suggest heterogeneity of surface adsorption, both in terms of the nature of adsorption sites and aggregation effects. Temperature dependent studies show that the activation energies for surface diffusion correlate with the size of the radical cation, suggesting that its movement rather than that of the electron dominates the observed kinetics. Monte Carlo simulations have been shown to give useful qualitative insights into the interpretation of the extracted parameters, in particular into how apparent distributions of rate constants can arise as a result of low surface dimensionality.
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Affiliation(s)
- David R Worrall
- Department of Chemistry, Loughborough University, Loughborough, Leicestershire
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Thomas JK. Physical Aspects of Radiation-Induced Processes on SiO2, γ-Al2O3, Zeolites, and Clays. Chem Rev 2005; 105:1683-734. [PMID: 15884787 DOI: 10.1021/cr020378a] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J K Thomas
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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von Seggern D, Modrakowski C, Spitz C, Dieter Schlüter A, Menzel R. Charge transfer initiated by optical excitation in diester substituted biphenylpyrene as a function of the solvent characterized by excited state absorption spectroscopy. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Worrall DR, Williams SL, Eremenko A, Smirnova N, Yakimenko O, Starukh G. Laser flash photolysis study of electron transfer processes of adsorbed anthracene on titania–silica surfaces. Colloids Surf A Physicochem Eng Asp 2003. [DOI: 10.1016/j.colsurfa.2003.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Zhang G, Thomas JK. Effect of Charge Stabilization on Electron Transfer Reactions in Zeolites. J Phys Chem B 2003. [DOI: 10.1021/jp022454j] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guohong Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - J. Kerry Thomas
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
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Lee DK, Kang YS. Electron Magnetic Resonance Studies on the Photoinduced Charge Separation of N-Methylphenothiazine in the Gel Matrixes of Phenyltriethoxysilane, Vinyltriethoxysilane, and Methyltriethoxysilane. J Phys Chem B 2003. [DOI: 10.1021/jp0211279] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Don Keun Lee
- Department of Chemistry, Pukyong National University, 599-1 Daeyeon-3-dong, Nam-gu, Pusan 608-737, Korea
| | - Young Soo Kang
- Department of Chemistry, Pukyong National University, 599-1 Daeyeon-3-dong, Nam-gu, Pusan 608-737, Korea
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Barzykin AV, Seki K, Tachiya M. Kinetics of diffusion-assisted reactions in microheterogeneous systems. Adv Colloid Interface Sci 2001; 89-90:47-140. [PMID: 11215811 DOI: 10.1016/s0001-8686(00)00053-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This review is focused on the basic theory of diffusion-assisted reactions in microheterogeneous systems, from porous solids to self-organized colloids and biomolecules. Rich kinetic behaviors observed experimentally are explained in a unified fashion using simple concepts of competing distance and time scales of the reaction and the embedding structure. We mainly consider pseudo-first-order reactions, such as luminescence quenching, described by the Smoluchowski type of equation for the reactant pair distribution function with a sink term defined by the reaction mechanism. Microheterogeneity can affect the microscopic rate constant. It also enters the evolution equation through various spatial constraints leading to complicated boundary conditions and, possibly, to the reduction of dimensionality of the diffusion space. The reaction coordinate and diffusive motion along this coordinate are understood in a general way, depending on the problem at hand. Thus, the evolution operator can describe translational and rotational diffusion of molecules in a usual sense, it can be a discrete random walk operator when dealing with hopping of adsorbates in solids, or it can correspond to conformational fluctuations in proteins. Mathematical formulation is universal but physical consequences can be different. Understanding the principal features of reaction kinetics in microheterogeneous systems enables one to extract important structural and dynamical information about the host environments by analyzing suitably designed experiments, it helps building effective strategies for computer simulations, and ultimately opens possibilities for designing systems with controllable reactivity properties.
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Affiliation(s)
- A V Barzykin
- National Institute of Materials and Chemical Research, Tsukuba, Ibaraki, Japan.
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Thomas JK, Ellison EH. Various aspects of the constraints imposed on the photochemistry of systems in porous silica. Adv Colloid Interface Sci 2001; 89-90:195-238. [PMID: 11215794 DOI: 10.1016/s0001-8686(00)00065-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This manuscript briefly reviews the photochemistry of organic molecules on porous silica (or SiO2). To gain an understanding of the chemistry on silica, data are displayed and discussed with respect to studies in homogeneous solution. In particular, the exact dimensionality of kinetic processes on porous SiO2 is a matter for debate. Hence, units of concentration of an adsorbate on the surface are expressed as moles per nanometer squared and as moles per liter, in order to compare with solution. Many studies show that organic molecules adsorb to SiO2 via the surface silanol (or surface hydroxyl OH) groups. The adsorption is heterogeneous, due to various clusters of silanol groups and to charge transfer (CT) sites. Photophysical studies clearly show these effects. The photo-induced reactions on SiO2 may be described by 'fractal' approaches, but a 'Gaussian' approach is often more useful to the photochemist. Photo-induced reactions occur via movement of the reactants on the surface, as in the case of the Langmuir-Hinshelwood (LH) mechanism or, as in the case of the Eley-Rideal (ER) mechanism, by bombardment of a surface bound excited state by a gaseous reactant, such as O2. Quenching of excited singlet states by O2 produces excited triplet states, which in turn are quenched to give singlet molecular oxygen. At room temperature the O2 quenching process on silica occurs by both mechanisms to approximately the same extent. However, the LH mechanism is dominant at lower temperatures and the ER mechanism is dominant at higher temperatures. Some quenchers, including carbon tetrachloride and tetranitromethane only quench by the LH mechanism giving rise to static quenching and chloro or nitro derivatives of the excited state. Photo-induced electron transfer between excited arenes and amines occurs readily, but the ionic products are short-lived compared to solution. This is due to the limited diffusion of the products on the surface, which in turn promotes back-electron transfer. Photoionization of arenes occurs on SiO2 via a two-photon process and gives very long-lived ions compared to solution. This is due to trapping of the photo-produced electrons by the SiO2 itself. Finally, the effects of co-adsorbants, including solvents, surfactants, and polymers, in photoreactions at the SiO2 surface are considered. The review ends with suggestions for future studies.
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Affiliation(s)
- J K Thomas
- Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556, USA.
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Eremenko A, Smirnova N, Rusina O, Linnik O, Eremenko T, Spanhel L, Rechthaler K. Photophysical properties of organic fluorescent probes on nanosized TIO 2 /SIO 2 systems prepared by the sol–gel method. J Mol Struct 2000. [DOI: 10.1016/s0022-2860(00)00448-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Furube A, Asahi T, Masuhara H, Yamashita H, Anpo M. Charge Carrier Dynamics of Standard TiO2 Catalysts Revealed by Femtosecond Diffuse Reflectance Spectroscopy. J Phys Chem B 1999. [DOI: 10.1021/jp984162h] [Citation(s) in RCA: 239] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Akihiro Furube
- Department of Applied Physics, Osaka University, Suita, Osaka 565−0871, and Department of Applied Chemistry, College of Engineering, University of Osaka Prefecture, Gakuen-cho 1-1, Sakai, Osaka 599-8531
| | - Tsuyoshi Asahi
- Department of Applied Physics, Osaka University, Suita, Osaka 565−0871, and Department of Applied Chemistry, College of Engineering, University of Osaka Prefecture, Gakuen-cho 1-1, Sakai, Osaka 599-8531
| | - Hiroshi Masuhara
- Department of Applied Physics, Osaka University, Suita, Osaka 565−0871, and Department of Applied Chemistry, College of Engineering, University of Osaka Prefecture, Gakuen-cho 1-1, Sakai, Osaka 599-8531
| | - Hiromi Yamashita
- Department of Applied Physics, Osaka University, Suita, Osaka 565−0871, and Department of Applied Chemistry, College of Engineering, University of Osaka Prefecture, Gakuen-cho 1-1, Sakai, Osaka 599-8531
| | - Masakazu Anpo
- Department of Applied Physics, Osaka University, Suita, Osaka 565−0871, and Department of Applied Chemistry, College of Engineering, University of Osaka Prefecture, Gakuen-cho 1-1, Sakai, Osaka 599-8531
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Borsarelli CD, Cosa JJ, Previtali CM. Photoinduced Charge Separation in Reverse Micelles Prepared with Benzylhexadecyldimethylammonium Chloride (BHDC). The Electron-Transfer Reaction between Pyrene and N,N-Dimethylaniline. Photochem Photobiol 1998. [DOI: 10.1111/j.1751-1097.1998.tb02497.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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