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Wild U, Hübner O, Meiners P, Kaifer E, Enders M, Himmel HJ. Intramolecular Through-Space Double-Electron Transfer Between A Pair of Redox-Active Guanidine Units Aligned by Dithiolate Bridges. Chemistry 2023; 29:e202302418. [PMID: 37606189 DOI: 10.1002/chem.202302418] [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: 07/27/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 08/23/2023]
Abstract
Using unconventional synthesis protocols, two redox-active triguanidine units are connected by a dithiolate bridge, aligning the two redox-active units in close proximity. The reduced, neutral and the tetracationic redox states with two dicationic triguanidine units are isolated and fully characterized. Then, the dicationic redox states are prepared by mixing the neutral and tetracationic molecules. At low temperatures, the dications are diamagnetic (singlet ground state) with two different triguanidine units (neutral and dicationic). At room temperature, the triplet state with two radical monocationic triguanidine units is populated. At low temperature (210 K), chemical exchange by intramolecular through-space electron-transfer between the two triguanidine units is evidenced by EXSY NMR spectroscopy. Intramolecular through-space transfer of two electrons from the neutral to the dicationic triguanidine unit is accompanied by migration of the counterions in opposite direction. The rate of double-electron transfer critically depends on the bridge. No electron-transfer is measured in the absence of a bridge (in a mixture of one dicationic and one neutral triguanidine), and relatively slow electron transfer if the bridge does not allow the two triguanidine units to approach each other close enough. The results give detailed, quantitative insight into the factors that influence intramolecular through-space double-electron-transfer processes.
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Affiliation(s)
- Ute Wild
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Olaf Hübner
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Paul Meiners
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Markus Enders
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hans-Jörg Himmel
- Anorganisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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2
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Williams ML, Schlesinger I, Jacobberger RM, Wasielewski MR. Mechanism of Ultrafast Triplet Exciton Formation in Single Cocrystals of π-Stacked Electron Donors and Acceptors. J Am Chem Soc 2022; 144:18607-18618. [PMID: 36178390 DOI: 10.1021/jacs.2c08584] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ultrafast triplet formation in donor-acceptor (D-A) systems typically occurs by spin-orbit charge-transfer intersystem crossing (SOCT-ISC), which requires a significant orbital angular momentum change and is thus usually observed when the adjacent π systems of D and A are orthogonal; however, the results presented here show that subnanosecond triplet formation occurs in a series of D-A cocrystals that form one-dimensional cofacial π stacks. Using ultrafast transient absorption microscopy, photoexcitation of D-A single cocrystals, where D is coronene (Cor) or pyrene (Pyr) and A is N,N-bis(3'-pentyl)-perylene-3,4:9,10-bis(dicarboximide) (C5PDI) or naphthalene-1,4:5,8-tetracarboxydianhydride (NDA), results in formation of the charge transfer (CT) excitons Cor•+-C5PDI•-, Pyr•+-C5PDI•-, Cor•+-NDA•-, and Pyr•+-NDA•- in <300 fs, while triplet exciton formation occurs in τ = 125, 106, 484, and 958 ps, respectively. TDDFT calculations show that the SOCT-ISC rates correlate with charge delocalization in the CT exciton state. In addition, time-resolved EPR spectroscopy shows that Cor•+-C5PDI•- and Pyr•+-C5PDI•- recombine to form localized 3*C5PDI excitons with zero-field splittings of |D| = 1170 and 1250 MHz, respectively. In contrast, Cor•+-NDA•- and Pyr•+-NDA•- give triplet excitons in which |D| is only 1240 and 690 MHz, respectively, compared to that of NDA (2091 MHz), which is the lowest energy localized triplet exciton, indicating that the Cor-NDA and Pyr-NDA triplet excitons have significant CT character. These results show that charge delocalization in CT excitons impacts both ultrafast triplet formation as well as the CT character of the resultant triplet states.
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Affiliation(s)
- Malik L Williams
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Itai Schlesinger
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Robert M Jacobberger
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R Wasielewski
- Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States
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3
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Kaur P, Singh K. Second-order nonlinear polarizability of "Push-Pull" chromophores. A decade of progress in donor-π-acceptor materials. CHEM REC 2022; 22:e202200024. [PMID: 35352466 DOI: 10.1002/tcr.202200024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/03/2022] [Indexed: 11/08/2022]
Abstract
Fine tuning and switching of nonlinear optical response of ferrocene chromophores has been an area of considerable significance as evidenced by a large number of reports in the current literature. In this personal account, we present linear/nonlinear behavior and structure-activity relationships of several classes of donor-π-acceptor designs using organometallic and organic materials, developed by our research group during the last decade. The results especially the electronic absorption spectral and the hyper-Rayleigh scattering have been supported by theoretical calculations. Exploiting the redox behavior of ferrocene donor, we have demonstrated switching of quadratic nonlinear optical responses with reversible redox chemistry, which is a useful attribute of nonlinear optical materials. Based on the ease in synthesis, structure diversification and structure-based large and switchable second-order optical nonlinearity, these materials are potential candidates for electro-optic applications.
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Affiliation(s)
- Paramjit Kaur
- Department of Chemistry, Centre of Advanced Study, Guru Nanak Dev University, Amritsar, 143 005, India
| | - Kamaljit Singh
- Department of Chemistry, Centre of Advanced Study, Guru Nanak Dev University, Amritsar, 143 005, India
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4
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He S, Lai R, Jiang Q, Han Y, Luo X, Tian Y, Liu X, Wu K. Engineering Sensitized Photon Upconversion Efficiency via Nanocrystal Wavefunction and Molecular Geometry. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Shan He
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Runchen Lai
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Qike Jiang
- State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Yaoyao Han
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
- University of the Chinese Academy of Sciences Beijing 100049 China
| | - Xiao Luo
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Yuyang Tian
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Xue Liu
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Kaifeng Wu
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
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5
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He S, Lai R, Jiang Q, Han Y, Luo X, Tian Y, Liu X, Wu K. Engineering Sensitized Photon Upconversion Efficiency via Nanocrystal Wavefunction and Molecular Geometry. Angew Chem Int Ed Engl 2020; 59:17726-17731. [DOI: 10.1002/anie.202009066] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Shan He
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Runchen Lai
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Qike Jiang
- State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Yaoyao Han
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
- University of the Chinese Academy of Sciences Beijing 100049 China
| | - Xiao Luo
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Yuyang Tian
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Xue Liu
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
| | - Kaifeng Wu
- State Key Laboratory of Molecular Reaction Dynamics Dynamics Research Center for Energy and Environmental Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian Liaoning 116023 China
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6
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Strong orbital interaction in a weak CH-π hydrogen bonding system. Sci Rep 2016; 6:22304. [PMID: 26927609 PMCID: PMC4772115 DOI: 10.1038/srep22304] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 02/08/2016] [Indexed: 02/07/2023] Open
Abstract
For the first time, the intermolecular orbital interaction between benzene and methane in the benzene-methane complex, a representative of weak interaction system, has been studied by us using ab initio calculations based on different methods and basis sets. Our results demonstrate obvious intermolecular orbital interaction between benzene and methane involving orbital overlaps including both occupied and unoccupied orbitals. Similar to interatomic orbital interaction, the intermolecular interaction of orbitals forms “bonding” and “antibonding” orbitals. In the interaction between occupied orbitals, the total energy of the complex increases because of the occupation of the antibonding orbital. The existence of the CH-π hydrogen bond between benzene and methane causes a decrease in rest energy level, leading to at least −1.51 kcal/mol intermolecular interaction energy. Our finding extends the concept of orbital interaction from the intramolecular to the intermolecular regime and gives a reliable explanation of the deep orbital reformation in the benzene-methane complex.
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7
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Li Y, Yu T, Li Z, Wang Z, Peng Q. Synthesis and characterization of main-chain, second-order, nonlinear optical polyurethanes with isolation moieties and zigzag structures. J Appl Polym Sci 2016. [DOI: 10.1002/app.42974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ying Li
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, and State Key Laboratory of Polymer Materials Engineering; Sichuan University; Chengdu 610064 People's Republic of China
| | - Ting Yu
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, and State Key Laboratory of Polymer Materials Engineering; Sichuan University; Chengdu 610064 People's Republic of China
| | - Zuojia Li
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, and State Key Laboratory of Polymer Materials Engineering; Sichuan University; Chengdu 610064 People's Republic of China
| | - Zhenguo Wang
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, and State Key Laboratory of Polymer Materials Engineering; Sichuan University; Chengdu 610064 People's Republic of China
| | - Qiang Peng
- Key Laboratory of Green Chemistry and Technology of the Ministry of Education, College of Chemistry, and State Key Laboratory of Polymer Materials Engineering; Sichuan University; Chengdu 610064 People's Republic of China
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8
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Gardner DM, Chen HF, Krzyaniak MD, Ratner MA, Wasielewski MR. Large Dipolar Spin–Spin Interaction in a Photogenerated U-Shaped Triradical. J Phys Chem A 2015; 119:8040-8. [DOI: 10.1021/acs.jpca.5b03048] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniel M. Gardner
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Hsiao-Fan Chen
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Matthew D. Krzyaniak
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Mark A. Ratner
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and
Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, United States
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9
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Chen HF, Gardner DM, Carmieli R, Wasielewski MR. Controlling the orientation of spin-correlated radical pairs by covalent linkage to nanoporous anodic aluminum oxide membranes. Chem Commun (Camb) 2014; 49:8614-6. [PMID: 23955433 DOI: 10.1039/c3cc45129a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ordered multi-spin assemblies are required for developing solid-state molecule-based spintronics. A linear donor-chromophore-acceptor (D-C-A) molecule was covalently attached inside the 150 nm diam. nanopores of an anodic aluminum oxide (AAO) membrane. Photoexcitation of D-C-A in a 343 mT magnetic field results in sub-nanosecond, two-step electron transfer to yield the spin-correlated radical ion pair (SCRP) (1)(D(+)˙-C-A(-)˙), which then undergoes radical pair intersystem crossing (RP-ISC) to yield (3)(D(+)˙-C-A(-)˙). RP-ISC results in S-T0 mixing to selectively populate the coherent superposition states |S'> and |T'>. Microwave-induced transitions between these states and the unpopulated |T(+1)> and |T(-1)> states result in spin-polarized time-resolved EPR (TREPR) spectra. The dependence of the electron spin polarization (ESP) phase of the TREPR spectra on the orientation of the AAO membrane pores relative to the externally applied magnetic field is used to determine the overall orientation of the SCRPs within the pores at room temperature.
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Affiliation(s)
- Hsiao-Fan Chen
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208-3113, USA.
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10
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Jiang L, Orimoto Y, Aoki Y. Stereoelectronic effects in Menshutkin-type S N
2 reactions: theoretical study based on through-space/bond orbital interaction analysis. J PHYS ORG CHEM 2013. [DOI: 10.1002/poc.3186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Lizhi Jiang
- Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences; Kyushu University; Kasuga Fukuoka 816-8580 Japan
| | - Yuuichi Orimoto
- Department of Material Sciences, Faculty of Engineering Sciences; Kyushu University; Kasuga Fukuoka 816-8580 Japan
| | - Yuriko Aoki
- Department of Material Sciences, Faculty of Engineering Sciences; Kyushu University; Kasuga Fukuoka 816-8580 Japan
- CREST; Japan Science and Technology Agency (JST); Kawaguchi Center Building, 4-1-8 Honcho Kawaguchi Saitama 332-0012 Japan
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11
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Wu W, Ye C, Qin J, Li Z. Introduction of an Isolation Chromophore into an “H”-Shaped NLO Polymer: Enhanced NLO Effect, Optical Transparency, and Stability. Chempluschem 2013; 78:1523-1529. [DOI: 10.1002/cplu.201300252] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Indexed: 11/05/2022]
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12
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Jiang L, Orimoto Y, Aoki Y. Substituent Effects on Menshutkin-Type Reactions in the Gas Phase and Solutions: Theoretical Approach from the Orbital Interaction View. J Chem Theory Comput 2013; 9:4035-45. [DOI: 10.1021/ct4006163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Lizhi Jiang
- Department of Molecular
and Material Sciences, Interdisciplinary Graduate School of Engineering
Sciences, Kyushu University, Kasuga Fukuoka
816-8580, Japan
| | - Yuuichi Orimoto
- Department
of Material Sciences, Faculty of Engineering Sciences, Kyushu University, Kasuga Fukuoka 816-8580, Japan
| | - Yuriko Aoki
- Department
of Material Sciences, Faculty of Engineering Sciences, Kyushu University, Kasuga Fukuoka 816-8580, Japan
- Group, CREST, Japan Science and Technology Agency (JST), Kawaguchi Center
Building, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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13
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Wu W, Yu G, Liu Y, Ye C, Qin J, Li Z. Using Two Simple Methods of ArArFSelf-Assembly and Isolation Chromophores to Further Improve the Comprehensive Performance of NLO Dendrimers. Chemistry 2012. [DOI: 10.1002/chem.201202992] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Taylor AJ, Davies ES, Weinstein JA, Sazanovich IV, Bouganov OV, Tikhomirov SA, Towrie M, McMaster J, Garner CD. Ultrafast Intramolecular Charge Separation in a Donor–Acceptor Assembly Comprising Bis(η5-cyclopentadienyl)molybdenum Coordinated to an Ene-1,2-dithiolate-naphthalenetetracarboxylicdiimide Ligand. Inorg Chem 2012; 51:13181-94. [DOI: 10.1021/ic301436t] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Adam J. Taylor
- School of Chemistry, University of Nottingham, Nottingham NG7 2 RD, United
Kingdom
| | - E. Stephen Davies
- School of Chemistry, University of Nottingham, Nottingham NG7 2 RD, United
Kingdom
| | - Julia A. Weinstein
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Igor V. Sazanovich
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | | | | | - Michael Towrie
- Central Laser Facility, Science
and Technology Facilities Council, Rutherford Appleton Laboratory, OX11 0QX, United Kingdom
| | - Jonathan McMaster
- School of Chemistry, University of Nottingham, Nottingham NG7 2 RD, United
Kingdom
| | - C. David Garner
- School of Chemistry, University of Nottingham, Nottingham NG7 2 RD, United
Kingdom
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15
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Colvin MT, Ricks AB, Wasielewski MR. Role of Bridge Energetics on the Preference for Hole or Electron Transfer Leading to Charge Recombination in Donor-Bridge-Acceptor Molecules. J Phys Chem A 2012; 116:2184-91. [DOI: 10.1021/jp2125735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Michael T. Colvin
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois
60208-3113, United States
| | - Annie Butler Ricks
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois
60208-3113, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois
60208-3113, United States
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16
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Ramírez MA, Cuadro AM, Alvarez-Builla J, Castaño O, Andrés JL, Mendicuti F, Clays K, Asselberghs I, Vaquero JJ. Donor-(π-bridge)-azinium as D-π-A+ one-dimensional and D-π-A(+)-π-D multidimensional V-shaped chromophores. Org Biomol Chem 2012; 10:1659-69. [PMID: 22241523 DOI: 10.1039/c2ob06427h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Heteroaromatic cations reacted with N-heteroarylacetylenes under Sonogashira conditions to allow easy access to potential single donor D-π-A(+) and V-shaped D-π-A(+)-π-D chromophores, where the acceptor moiety A is the π-deficient pyridinium cation and the donor moiety is represented by different π-excessive N-heterocycles. The β hyperpolarizabilities were measured using hyper-Rayleigh scattering experiments and the experimental data are supported by a theoretical analysis that combines a variety of computational procedures, including Density Functional Theory (DFT) and correlated Hartree-Fock-based methods (RCIS(D)).
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Affiliation(s)
- Marco Antonio Ramírez
- Departamento de Química Orgánica, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain
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Shpaisman H, Seitz O, Yaffe O, Roodenko K, Scheres L, Zuilhof H, Chabal YJ, Sueyoshi T, Kera S, Ueno N, Vilan A, Cahen D. Structure Matters: Correlating temperature dependent electrical transport through alkyl monolayers with vibrational and photoelectron spectroscopies. Chem Sci 2012. [DOI: 10.1039/c1sc00639h] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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18
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Liu Z, Lu GY, Ma J. Tuning the absorption spectra and nonlinear optical properties of D-π-A azobenzene derivatives by changing the dipole moment and conjugation length: a theoretical study. J PHYS ORG CHEM 2010. [DOI: 10.1002/poc.1792] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Li MX, Han K, Li HP, Ge Y, Wu QH, Tang G, Wu YX. Theoretical study on the nonlinear optical properties of donor/acceptor-functionalized trigonal dehydrobenzoannulenes. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.theochem.2010.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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20
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Silva BPG, Marcon RO, Brochsztain S. Inclusion complexes of cyclodextrins with 4-amino-1,8-naphthalimides (part 2). J INCL PHENOM MACRO 2010. [DOI: 10.1007/s10847-010-9790-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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21
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Li Z, Hu P, Yu G, Zhang W, Jiang Z, Liu Y, Ye C, Qin J, Li Z. “H”-shape second order NLO polymers: synthesis and characterization. Phys Chem Chem Phys 2009; 11:1220-6. [DOI: 10.1039/b816246h] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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22
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Goldsmith RH, Vura-Weis J, Scott AM, Borkar S, Sen A, Ratner MA, Wasielewski MR. Unexpectedly Similar Charge Transfer Rates through Benzo-Annulated Bicyclo[2.2.2]octanes. J Am Chem Soc 2008; 130:7659-69. [DOI: 10.1021/ja8004623] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Randall H. Goldsmith
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Josh Vura-Weis
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Amy M. Scott
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Sachin Borkar
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Ayusman Sen
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Mark A. Ratner
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
| | - Michael R. Wasielewski
- Department of Chemistry, Argonne-Northwestern Solar Energy Research (ANSER) Center, and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208 and the Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
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Chernick ET, Mi Q, Vega AM, Lockard JV, Ratner MA, Wasielewski MR. Controlling Electron Transfer Dynamics in Donor−Bridge−Acceptor Molecules by Increasing Unpaired Spin Density on the Bridge. J Phys Chem B 2007; 111:6728-37. [PMID: 17309293 DOI: 10.1021/jp068741v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A t-butylphenylnitroxide (BPNO*) stable radical is attached to an electron donor-bridge-acceptor (D-B-A) system having well-defined distances between the components: MeOAn-6ANI-Ph(BPNO*)-NI, where MeOAn=p-methoxyaniline, 6ANI=4-(N-piperidinyl)naphthalene-1,8-dicarboximide, Ph=phenyl, and NI=naphthalene-1,8:4,5-bis(dicarboximide). MeOAn-6ANI, BPNO*, and NI are attached to the 1, 3, and 5 positions of the Ph bridge, respectively. Time-resolved optical and EPR spectroscopy show that BPNO* influences the spin dynamics of the photogenerated triradical states 2,4(MeOAn+*-6ANI-Ph(BPNO*)-NI-*), resulting in slower charge recombination within the triradical, as compared to the corresponding biradical lacking BPNO*. The observed spin-spin exchange interaction between the photogenerated radicals MeOAn+* and NI-* is not altered by the presence of BPNO*. However, the increased spin density on the bridge greatly increases radical pair (RP) intersystem crossing from the photogenerated singlet RP to the triplet RP. Rapid formation of the triplet RP makes it possible to observe a biexponential decay of the total RP population with components of tau=740 ps (0.75) and 104 ns (0.25). Kinetic modeling shows that the faster decay rate is due to rapid establishment of an equilibrium between the triplet RP and the neutral triplet state resulting from charge recombination, whereas the slower rate monitors recombination of the singlet RP to ground state.
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Affiliation(s)
- Erin T Chernick
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208-3113, USA
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24
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Regehly M, Ermilov EA, Helmreich M, Hirsch A, Jux N, Röder B. Photoinduced Energy and Electron Transfer Processes in Hexapyropheophorbide a- Fullerene [C60] Molecular Systems. J Phys Chem B 2007; 111:998-1006. [PMID: 17266254 DOI: 10.1021/jp065626b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The photophysical properties of the novel hexapyropheophorbide a (P6), and hexakis (pyropheophorbide a)-C60 (FP6) were studied and compared with those of hexakis (pyropheophorbide a)-fullerene [5:1] hexaadduct (FHP6). It was found that after light absorption the pyropheophorbide a molecules in all three compounds undergo very efficient energy transfer as well as partly excitonic interactions. The last process results in the formation of energy traps, which could be resolved experimentally. For P6, due to shorter distances between neighboring dye molecules, stronger interactions between pyropheophorbide a units than for FHP6 were observed. As a consequence, the excitation energy is delivered rapidly to traps formed by stacked pyropheophorbide a molecules resulting in the reduction of fluorescence, intersystem crossing, and singlet oxygen quantum yields compared to the values of FHP6. For FP6 the reduction of these values is much stronger due to an additional fast and efficient deactivation process, namely photoinduced electron transfer from pyropheophorbide a to the fullerene moiety. Consequently, FP6 can be considered as a combination of a light-harvesting system consisting of several separate pyropheophorbide a molecules and a charge-separating center.
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Affiliation(s)
- Martin Regehly
- Institut für Physik, Photobiophysik, Humboldt Universität, Newtonstr. 15, D-12489 Berlin, Germany
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25
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Goldsmith RH, Wasielewski MR, Ratner MA. Electron Transfer in Multiply Bridged Donor−Acceptor Molecules: Dephasing and Quantum Coherence. J Phys Chem B 2006; 110:20258-62. [PMID: 17034204 DOI: 10.1021/jp0639187] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a simple theoretical treatment of nonadiabatic electron transfer in multiply bridged donor-bridge-acceptor molecules using the density matrix formalism. Destructive interference can result from different signed couplings between bridge sites, with the simplest system being a four-site Joachim-type molecular interferometer. Previous work has shown that deposition of energy on the bridge sites erases the interference and recovers transport. We show that pure local dephasing, a completely elastic process, is also capable of eliminating destructive interference and regaining transport. Destructive interference as a result of system connectivity can explain the familiar ortho-meta-para reactivity of benzene bridges. We also show that pure dephasing can yield a coalescence of ortho, meta, and para effective coupling strengths and suggest a system to observe this effect experimentally.
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Affiliation(s)
- Randall H Goldsmith
- Center for Nanofabrication and Molecular Self-Assembly, Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
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26
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Dance ZEX, Mi Q, McCamant DW, Ahrens MJ, Ratner MA, Wasielewski MR. Time-Resolved EPR Studies of Photogenerated Radical Ion Pairs Separated by p-Phenylene Oligomers and of Triplet States Resulting from Charge Recombination. J Phys Chem B 2006; 110:25163-73. [PMID: 17165960 DOI: 10.1021/jp063690n] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Photoexcitation of a series of donor-bridge-acceptor (D-B-A) systems, where D = phenothiazine (PTZ), B = p-phenylene (Phn), n = 1-5, and A= perylene-3,4:9,10-bis(dicarboximide) (PDI) results in rapid electron transfer to produce 1(PTZ+*-Phn-PDI-*). Time-resolved EPR (TREPR) studies of the photogenerated radical pairs (RPs) show that above 150 K, when n = 2-5, the radical pair-intersystem crossing mechanism (RP-ISC) produces spin-correlated radical ion pairs having electron spin polarization patterns indicating that the spin-spin exchange interaction in the radical ion pair is positive, 2J > 0, and is temperature dependent. This temperature dependence is most likely due to structural changes of the p-phenylene bridge. Charge recombination in the RPs generates PTZ-Phn-3*PDI, which exhibits a spin-polarized signal similar to that observed in photosynthetic reaction-center proteins and some biomimetic systems. At temperatures below 150 K and/or at shorter donor-acceptor distances, e.g., when n = 1, PTZ-Phn-3*PDI is also formed from a competitive spin-orbit-intersystem crossing (SO-ISC) mechanism that is a result of direct charge recombination: 1(PTZ+*-Phn-PDI-*) --> PTZ-Phn-3*PDI. This SO-ISC mechanism requires the initial RP intermediate and depends strongly on the orientation of the molecular orbitals involved in the charge recombination as well as the magnitude of 2J.
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Affiliation(s)
- Zachary E X Dance
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208-3113, USA
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27
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Wasielewski MR. Energy, Charge, and Spin Transport in Molecules and Self-Assembled Nanostructures Inspired by Photosynthesis. J Org Chem 2006; 71:5051-66. [PMID: 16808492 DOI: 10.1021/jo060225d] [Citation(s) in RCA: 479] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Electron transfer in biological molecules provides both insight and inspiration for developing chemical systems having similar functionality. Photosynthesis is an example of an integrated system in which light harvesting, photoinduced charge separation, and catalysis combine to carry out two thermodynamically demanding processes, the oxidation of water and the reduction of carbon dioxide. The development of artificial photosynthetic systems for solar energy conversion requires a fundamental understanding of electron-transfer reactions between organic molecules. Since these reactions most often involve single-electron transfers, the spin dynamics of photogenerated radical ion pairs provide important information on how the rates and efficiencies of these reactions depend on molecular structure. Given this knowledge, the design and synthesis of large integrated structures to carry out artificial photosynthesis is moving forward. An important approach to achieving this goal is the development of small, functional building blocks, having a minimum number of covalent bonds, which also have the appropriate molecular recognition sites to facilitate self-assembly into a complete, functional artificial photosynthetic system.
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Affiliation(s)
- Michael R Wasielewski
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, IL 60208-3113, USA.
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Mi Q, Chernick ET, McCamant DW, Weiss EA, Ratner MA, Wasielewski MR. Spin Dynamics of Photogenerated Triradicals in Fixed Distance Electron Donor−Chromophore−Acceptor−TEMPO Molecules. J Phys Chem A 2006; 110:7323-33. [PMID: 16759120 DOI: 10.1021/jp061218w] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The stable free radical 2,2,6,6-tetramethylpiperidinoxyl (TEMPO, T*) was covalently attached to the electron acceptor in a donor-chromophore-acceptor (D-C-A) system, MeOAn-6ANI-Phn-A-T*, having well-defined distances between each component, where MeOAn = p-methoxyaniline, 6ANI = 4-(N-piperidinyl)naphthalene-l,8-dicarboximide, Ph = 2,5-dimethylphenyl (n = 0,1), and A = naphthalene-1,8:4,5-bis(dicarboximide) (NI) or pyromellitimide (PI). Using both time-resolved optical and EPR spectroscopy, we show that T* influences the spin dynamics of the photogenerated triradical states 2,4(MeOAn+*-6ANI-Phn-A-*-T*), resulting in modulation of the charge recombination rate within the triradical compared with the corresponding biradical lacking T*. The observed spin-spin exchange interaction between the photogenerated radicals MeOAn+* and A-* is not altered by the presence of T*, which interacts most strongly with A-* and accelerates radical pair intersystem crossing. Charge recombination within the triradicals results in the formation of 2,4(MeOAn-6ANI-Phn-3*NI-T*) or 2,4(MeOAn-3*6ANI-Phn-PI-T*) in which T* is strongly spin polarized in emission. Normally, the spin dynamics of correlated radical pairs do not produce a net spin polarization; however, the rate at which the net spin polarization appears on T* closely follows the photogenerated radical ion pair decay rate. This effect is attributed to antiferromagnetic coupling between T* and the local triplet state 3NI, which is populated following charge recombination. These results are explained using a switch in the spin basis set between the triradical and the three-spin charge recombination product having both T* and 3*NI or 3*6ANI present.
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Affiliation(s)
- Qixi Mi
- Department of Chemistry and International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208-3113, USA
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29
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Photoinduced electron transfer through hydrogen bonds in a rod-like donor–acceptor molecule: A time-resolved EPR study. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.11.044] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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30
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Chernick ET, Mi Q, Kelley RF, Weiss EA, Jones BA, Marks TJ, Ratner MA, Wasielewski MR. Electron Donor−Bridge−Acceptor Molecules with Bridging Nitronyl Nitroxide Radicals: Influence of a Third Spin on Charge- and Spin-Transfer Dynamics. J Am Chem Soc 2006; 128:4356-64. [PMID: 16569012 DOI: 10.1021/ja0576435] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Appending a stable radical to the bridge molecule in a donor-bridge-acceptor system (D-B-A) is potentially an important way to control charge- and spin-transfer dynamics through D-B-A. We have attached a nitronyl nitroxide (NN*) stable radical to a D-B-A system having well-defined distances between the components: MeOAn-6ANI-Ph(NN*)-NI, where MeOAn = p-methoxyaniline, 6ANI = 4-(N-piperidinyl)naphthalene-1,8-dicarboximide, Ph = phenyl, and NI = naphthalene-1,8:4,5-bis(dicarboximide). MeOAn-6ANI, NN*, and NI are attached to the 1, 3, and 5 positions of the Ph bridge. Using both time-resolved optical and EPR spectroscopy, we show that NN* influences the spin dynamics of the photogenerated triradical states (2,4)(MeOAn(+)*-6ANI-Ph(NN*)-NI(-)*), resulting in slower charge recombination within the triradical compared to the corresponding biradical lacking NN*. The observed spin-spin exchange interaction between the photogenerated radicals MeOAn(+)(*) and NI(-)(*) is not altered by the presence of NN*, which only accelerates radical pair intersystem crossing. Charge recombination within the triradical results in the formation of (2,4)(MeOAn-6ANI-Ph(NN*)-(3)NI), in which NN* is strongly spin-polarized. Normally, the spin dynamics of correlated radical pairs do not produce a net spin polarization; however, net spin polarization appears on NN* with the same time constant as describes the photogenerated radical ion pair decay. This effect is attributed to antiferromagnetic coupling between NN* and the local triplet state (3)NI, which is populated following charge recombination. This requires an effective switch in the spin basis set between the triradical and the three-spin charge recombination product having both NN* and (3)NI present.
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Affiliation(s)
- Erin T Chernick
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
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31
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Ilhan F, Tyson DS, Stasko DJ, Kirschbaum K, Meador MA. Twisted, Z-Shaped Perylene Bisimide. J Am Chem Soc 2005; 128:702-3. [PMID: 16417343 DOI: 10.1021/ja056912o] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The first derivative of a new class of perylene bisimide chromophores, N,N'-bis(octyl)-3,9-bis(phenyl)perylene-1,2,7,8-tetracarboxyl bisimide, 1, has been synthesized and its fundamental photophysical and electrochemical properties assessed. The extended, Z-shaped structure was achieved by use of the classic photoenolization of an o-methylbenzophenone analogue, 1,5-dibenzoyl-9,10-dihydroanthracene, and in situ Diels-Alder trapping of the resulting o-xylylenol intermediates with N-octylmaleimide. Subsequent dehydration and aromatization of the resulting bisadduct afforded 1. In dichloromethane, bisimide 1 has an absorption lambdamax at 491 nm (epsilon = 29,600 M-1 cm-1), a fluorescence lambdamax at 517 nm with a high quantum yield (Phi = 0.70), and a single-exponential fluorescence decay (tau = 5.01 ns). Pure crystals of 1 have red emission, suggesting exciplex formation in the solid state. X-ray crystallographic analysis of 1 revealed significant twisting of its perylene core.
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Affiliation(s)
- Faysal Ilhan
- Polymers Branch, Materials and Structures Division, NASA Glenn Research Center, 21000 Brookpark Road, Cleveland, Ohio 44135, USA
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Weiss EA, Tauber MJ, Kelley RF, Ahrens MJ, Ratner MA, Wasielewski MR. Conformationally Gated Switching between Superexchange and Hopping within Oligo-p-phenylene-Based Molecular Wires. J Am Chem Soc 2005; 127:11842-50. [PMID: 16104763 DOI: 10.1021/ja052901j] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We observe well-defined regions of superexchange and thermally activated hopping in the temperature dependence of charge recombination (CR) in a series of donor-bridge-acceptor (D-B-A) systems, where D = phenothiazine (PTZ), B = p-phenylene (Ph(n)), n = 1-4, and A = perylene-3,4:9,10-bis(dicarboximide) (PDI). A fit to the thermally activated CR rates of the n = 3 and n = 4 compounds yields activation barriers of 1290 and 2030 cm(-1), respectively, which match closely with theoretically predicted and experimentally observed barriers for the planarization of terphenyl and quaterphenyl. Negative activation of CR in the temperature regions dominated by superexchange charge transport is the result of a fast conformational equilibrium that increasingly depopulates the reactive state for CR as temperature is increased. The temperature dependence of the effective donor-acceptor superexchange coupling, V(DA), measured using magnetic field effects on the efficiency of the charge recombination process, shows that CR occurs out of the conformation with lower V(DA) via the energetically favored triplet pathway.
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Affiliation(s)
- Emily A Weiss
- Center for Nanofabrication and Molecular Self-Assembly and Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
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Weiss EA, Tauber MJ, Ratner MA, Wasielewski MR. Electron Spin Dynamics as a Probe of Molecular Dynamics: Temperature-Dependent Magnetic Field Effects on Charge Recombination within a Covalent Radical Ion Pair. J Am Chem Soc 2005; 127:6052-61. [PMID: 15839706 DOI: 10.1021/ja043398y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The electron spin-spin exchange interaction, 2J, in radical pairs (RPs) is exquisitely sensitive to the details of molecular structure and can thus serve as an important probe of structural dynamics in RPs of potential interest to photonic and electronic devices. Photoinitiated ultrafast two-step charge separation produces (1)(MeOAn(+)(*)-6ANI-NI(-)(*)), where MeOAn = p-methoxyaniline, 6ANI = 4-(N-piperidinyl)naphthalene-1,8-dicarboximide, and NI = naphthalene-1,8:4,5-bis(dicarboximide). Radical pair intersystem crossing subsequently produces (3)(MeOAn(+)(*)-6ANI-NI(-)(*)), and the total RP population decays with approximately 10 ns lifetime at 140 K, which increases to nearly 30 ns at 300 K in toluene. The activation energy observed for this process is negative and can be explained by a mechanism involving a conformational preequilibrium of the RP followed by charge recombination. Over the same temperature range, the magnetic field effect (MFE) on yield of the triplet recombination product, MeOAn-6ANI-(3)()NI, yields the magnitude of 2J, which directly monitors the superexchange electronic coupling for charge recombination. A single resonance in the MFE plot is observed at 300 K, which splits into two resonances at temperatures below 230 K, suggesting that there are two distinct groups of RP conformations at low temperature. The magnitude of 2J for the lower field resonance (10 mT) at 140 K is 5 times smaller than that of the high field resonance. At 300 K the equilibrium is shifted almost entirely to the set of conformers with the stronger electronic coupling. The motion that couples these two groups of conformations is the motion that most effectively gates the donor-acceptor electronic coupling.
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Affiliation(s)
- Emily A Weiss
- Center for Nanofabrication and Molecular Self-Assembly and Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, USA
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35
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Chernick ET, Ahrens MJ, Scheidt KA, Wasielewski MR. Copper-Promoted N-Arylations of Cyclic Imides within Six-Membered Rings: A Facile Route to Arylene-Based Organic Materials. J Org Chem 2005; 70:1486-9. [PMID: 15704992 DOI: 10.1021/jo0481351] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
[reaction: see text] Cyclic imides within six-membered rings are shown to undergo efficient N-arylation using various arylboronic esters mediated by copper(II) acetate in the presence of an amine base and oxygen atmosphere with gentle heating. Until now, the synthesis of N-arylated cyclic imides having six-membered rings was restricted largely to strongly heating anilines in the presence of anhydrides. This reaction is applicable to the synthesis of new organic materials based on arylene imide and bis(imide) dyes, such as perylene-3,4:9,10-bis(dicarboximide)s.
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Affiliation(s)
- Erin T Chernick
- Department of Chemistry and Center for Nanofabrication and Molecular Self-Assembly, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
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