1
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Shioukhi I, Batchu H, Schwartz G, Minion L, Deree Y, Bogoslavsky B, Shimon LJW, Wade J, Hoffman R, Fuchter MJ, Markovich G, Gidron O. Helitwistacenes-Combining Lateral and Longitudinal Helicity Results in Solvent-Induced Inversion of Circularly Polarized Light. Angew Chem Int Ed Engl 2024; 63:e202319318. [PMID: 38224528 DOI: 10.1002/anie.202319318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/17/2024]
Abstract
Helicity is expressed differently in ortho- and para-fused acenes-helicenes and twistacenes, respectively. While the extent of helicity is constant in helicenes, it can be tuned in twistacenes, and the handedness of flexible twistacenes is often determined by more rigid helicenes. Here, we combine helicenes with rigid twistacenes consisting of a tunable degree of twisting, forming helitwistacenes. While the X-ray structures reveal that the connection does not affect the helicity of each moiety, their electronic circular dichroism (ECD) and circularly polarized luminescence (CPL) spectra are strongly affected by the helicity of the twistacene unit, resulting in solvent-induced sign inversion. ROESY NMR and TD-DFT calculations support this observation, which is explained by differences in the relative orientation of the helicene and twistacene moieties.
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Affiliation(s)
- Israa Shioukhi
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel
| | - Harikrishna Batchu
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel
| | - Gal Schwartz
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Louis Minion
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, White City Campus, 82 Wood Lane, W12 0BZ, London, U.K
| | - Yinon Deree
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel
| | - Benny Bogoslavsky
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel
| | - Linda J W Shimon
- Chemical Research Support Unit, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Jessica Wade
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, White City Campus, 82 Wood Lane, W12 0BZ, London, U.K
- Department of Materials, Royal School of Mines, Imperial College London, SW7 2AZ, London, U.K
| | - Roy Hoffman
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel
| | - Matthew J Fuchter
- Molecular Sciences Research Hub, Department of Chemistry, Imperial College London, White City Campus, 82 Wood Lane, W12 0BZ, London, U.K
| | - Gil Markovich
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Ori Gidron
- Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel
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2
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Agrawal AR, Shiouki I, Deree Y, Bogoslavsky B, Gidron O. Controlling helicene's pitch by molecular tethering. Org Biomol Chem 2024; 22:1365-1368. [PMID: 38258458 DOI: 10.1039/d3ob02075d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
We applied post-cyclization annulation to introduce a series of tethered S-shaped double [4]helicenes in which the intramolecular tether imposes a specific helical handedness. Introducing a tether and then shortening the tether length incrementally increase the pitch angle of [4]helicene, thus enabling a quantitative study of the effects of helicene's pitch on its electronic and (chiro)optical properties.
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Affiliation(s)
- Abhijeet R Agrawal
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel.
| | - Israa Shiouki
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel.
| | - Yinon Deree
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel.
| | - Benny Bogoslavsky
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel.
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel.
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3
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Dishi O, Rahav Y, Gidron O. π-Conjugated oligofuran macrocycles. Chem Commun (Camb) 2024; 60:522-529. [PMID: 38109063 DOI: 10.1039/d3cc05225g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
This Feature Article overviews a new class of π-conjugated materials - macrocyclic furans. Starting from their synthesis, we review their unique structural, optical and electronic properties, chemical reactivity, and potential application as synthons. Finally, we discuss the study of oligofuran macrocycles as a model system for exploring the concept of global aromaticity and the size limitation of Hückel's rule in neutral macrocycles.
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Affiliation(s)
- Or Dishi
- The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel.
| | - Yuval Rahav
- The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel.
| | - Ori Gidron
- The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel.
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4
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Rahav Y, Rajagopal SK, Dishi O, Bogoslavsky B, Gidron O. Alternating behavior in furan-acetylene macrocycles reveals the size-dependency of Hückel's rule in neutral molecules. Commun Chem 2023; 6:100. [PMID: 37244950 DOI: 10.1038/s42004-023-00902-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/15/2023] [Indexed: 05/29/2023] Open
Abstract
Aromaticity can be assigned by Hückel's rule, which predicts that planar rings with delocalized (4n + 2) π-electrons are aromatic, whereas those with 4n π-electrons are antiaromatic. However, for neutral rings, the maximal value of "n" to which Hückel's rule applies remains unknown. Large macrocycles exhibiting global ring current can serve as models for addressing this question, but the global ring current are often overshadowed in these molecules by the local ring current of the constituent units. Here, we present a series of furan-acetylene macrocycles, ranging from the pentamer to octamer, whose neutral states display alternating contributions from global aromatic and antiaromatic ring currents. We find that the odd-membered macrocycles display global aromatic characteristics, whereas the even-membered macrocycles display contributions from globally antiaromatic ring current. These factors are expressed electronically (oxidation potentials), optically (emission spectra), and magnetically (chemical shifts), and DFT calculations predict global ring current alternations up to 54 π-electrons.
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Affiliation(s)
- Yuval Rahav
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Shinaj K Rajagopal
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Or Dishi
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Benny Bogoslavsky
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Ori Gidron
- Institute of Chemistry, The Center for Nanoscience and Nanotechnology, Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel.
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5
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Amsallem D, Kumar A, Naaman R, Gidron O. Spin polarization through axially chiral linkers: Length dependence and correlation with the dissymmetry factor. Chirality 2023. [PMID: 36896481 DOI: 10.1002/chir.23556] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/17/2023] [Accepted: 02/24/2023] [Indexed: 03/11/2023]
Abstract
The chiral-induced spin selectivity (CISS) effect relates to the spin-selective electron transport through chiral molecules; therefore, the chiral molecules act as spin filters. In past studies, correlation was found between the magnitude of the spin filtering and the intensity of the circular dichroism (CD) spectrum (the first Compton peak) of the molecules. Since the intensity of the CD peak relates to both the magnitude of the electric and magnetic dipole transitions, it was not clear which of these properties correlate with the CISS effect. This work aims at addressing this question. By studying the spin-dependent conduction and the CD spectra of the thiol-functionalized enantiopure binaphthalene (BINAP) and ternaphthalene (TERNAP), we found that both BINAP and TERNAP exhibit a similar spin polarization of 50%, despite the first Compton peak in TERNAP being almost twice as intense as the peak in BINAP. These results can be explained by the similar values of their anisotropy (or dissymmetry) factor, gabs , which is proportional to the magnetic transition dipole moment. Hence, we concluded that the CISS effect is proportional to the transition dipole moment in chiral molecules, namely, to the dissymmetry factor.
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Affiliation(s)
- Dana Amsallem
- Institute of Chemistry, Center for Nanoscience and Nanotechnology and the Cazalli Institute, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Anil Kumar
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot, Israel
| | - Ron Naaman
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot, Israel
| | - Ori Gidron
- Institute of Chemistry, Center for Nanoscience and Nanotechnology and the Cazalli Institute, The Hebrew University of Jerusalem, Jerusalem, Israel
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6
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Bedi A, Schwartz G, Hananel U, Manor Armon A, Shioukhi I, Markovich G, Gidron O. The effect of axial and helical chirality on circularly polarized luminescence: lessons learned from tethered twistacenes. Chem Commun (Camb) 2023; 59:2011-2014. [PMID: 36723083 DOI: 10.1039/d2cc07074j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effect of axial and helical twisting on the circularly polarized luminescence of acenes was studied both experimentally and computationally, using four series of tethered twisted acenes. We find that the combination of axial and helical chirality yields the highest anisotropy factors, and that the ratio between the absorption and emission anisotropy factors is an intrinsic property for twistacenes.
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Affiliation(s)
- Anjan Bedi
- Institute of Chemistry, Center for Nanoscience and Nanotechnology and the Cazalli Institute, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Gal Schwartz
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Uri Hananel
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Amit Manor Armon
- Institute of Chemistry, Center for Nanoscience and Nanotechnology and the Cazalli Institute, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Israa Shioukhi
- Institute of Chemistry, Center for Nanoscience and Nanotechnology and the Cazalli Institute, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Gil Markovich
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Ori Gidron
- Institute of Chemistry, Center for Nanoscience and Nanotechnology and the Cazalli Institute, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
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7
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Metzger TS, Batchu H, Kumar A, Fedotov DA, Goren N, Bhowmick DK, Shioukhi I, Yochelis S, Schapiro I, Naaman R, Gidron O, Paltiel Y. Optical Activity and Spin Polarization: The Surface Effect. J Am Chem Soc 2023; 145:3972-3977. [PMID: 36765468 DOI: 10.1021/jacs.2c10456] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Chirality ('handedness') is a property that underlies a broad variety of phenomena in nature. Chiral molecules appear in two forms, and each is a mirror image of the other, the two enantiomers. The chirality of molecules is associated with their optical activity, and circular dichroism is commonly applied to identify the handedness of chiral molecules. Recently, the chiral induced spin selectivity (CISS) effect was established, according to which transfer of electrons within chiral molecules depends on the electron's spin. Which spin is preferred depends on the handedness of the chiral molecule and the direction of motion of the electron. Several experiments in the past indicated that there may be a relation between the optical activity of the molecules and their spin selectivity. Here, we show that for a molecule containing several stereogenic axes, when adsorbed on a metal substrate, the peaks in the CD spectra have the same signs for the two enantiomers. This is not the case when the molecules are adsorbed on a nonmetallic substrate or dissolved in solution. Quantum chemical simulations are able to explain the change in the CD spectra upon adsorption of the molecules on conductive and nonconductive surfaces. Surprisingly, the CISS properties are similar for the two enantiomers when adsorbed on the metal substrate, while when the molecules are adsorbed on nonmetallic surface, the preferred spin depends on the molecule handedness. This correlation between the optical activity and the CISS effect indicates that the CISS effect relates to the global polarizability of the molecule.
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Affiliation(s)
- Tzuriel S Metzger
- Department of Applied Physics and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Harikrishna Batchu
- Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Anil Kumar
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot 76100, Israel
| | - Daniil A Fedotov
- Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Naama Goren
- Department of Applied Physics and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Deb Kumar Bhowmick
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot 76100, Israel
| | - Israa Shioukhi
- Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Shira Yochelis
- Department of Applied Physics and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Igor Schapiro
- Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Ron Naaman
- Department of Chemical and Biological Physics, Weizmann Institute, Rehovot 76100, Israel
| | - Ori Gidron
- Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
| | - Yossi Paltiel
- Department of Applied Physics and Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 9190401, Israel
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8
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Rajagopal SK, Dishi O, Bogoslavsky B, Gidron O. Transformation of π-conjugated macrocycles: from furanophanes to napthalenophanes. Chem Commun (Camb) 2022; 58:13652-13655. [PMID: 36412186 DOI: 10.1039/d2cc05434e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Applying sequential Diels-Alder cycloaddition and deoxygenation to small π-conjugated furan macrocycles fully converts them to 1,4-naphthalophanes with either ethylene or acetylene spacers, depending on the reaction conditions. 1,4-Napthalenophane tetraene exhibits a 1,3-alternating conformation in the solid state, inclusion of solvent molecules within the macrocycle, and low reduction potentials.
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Affiliation(s)
- Shinaj K Rajagopal
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Or Dishi
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Benny Bogoslavsky
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
| | - Ori Gidron
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
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9
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Dishi O, Rahav Y, Carmieli R, Gidron O. A Macrocyclic Furan with Accessible Oxidation States: Switching Between Aromatic and Antiaromatic Global Ring Currents. Chemistry 2022; 28:e202202082. [PMID: 35932151 PMCID: PMC9826138 DOI: 10.1002/chem.202202082] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Indexed: 01/11/2023]
Abstract
Macrocyclic furans are predicted to switch between global aromaticity and antiaromaticity, depending on their oxidation states. However, the macrocyclic furans reported to date are stabilized by electron withdrawing groups, which result in inaccessible oxidation states. To circumvent this problem, a post-macrocyclization approach was applied to introduce methylene-substituted macrocyclic furans, which display an extremely low oxidation potential of -0.23 vs. Fc/Fc+ , and are partially oxidized in ambient conditions. Additional oxidation to the dication results in aromaticity switching to a global 30πe- aromatic state, as indicated by the formation of a strong diatropic current observed in the 1 H NMR spectrum. NICS and ACID calculations support this trend and provide evidence for a different pathway for the global current in the neutral and dicationic states. According to these findings, macrocyclic furans can be rendered as promising p-type materials with stable oxidation states.
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Affiliation(s)
- Or Dishi
- Institute of ChemistryThe Hebrew University of JerusalemEdmond J. Safra CampusJerusalem9190401Israel
| | - Yuval Rahav
- Institute of ChemistryThe Hebrew University of JerusalemEdmond J. Safra CampusJerusalem9190401Israel
| | - Raanan Carmieli
- Chemical Research Support UnitWeizmann Institute of ScienceRehovot7610001Israel
| | - Ori Gidron
- Institute of ChemistryThe Hebrew University of JerusalemEdmond J. Safra CampusJerusalem9190401Israel
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10
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Malakar P, Borin V, Bedi A, Schapiro I, Gidron O, Ruhman S. The impact of twisting on the intersystem crossing in acenes: an experimental and computational study. Phys Chem Chem Phys 2022; 24:2357-2362. [PMID: 35018908 DOI: 10.1039/d1cp05728f] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Due to their unique excited state dynamics, acenes play a dominant role in optoelectronic and light-harvesting applications. Their optical and electronic properties are typically tailored by side-group engineering, which often result in distortion of the acene core from planarity. However, the effect of such distortion on their excited state dynamics is not clear. In this work, we investigate the effect of twisting on the photophysics of acenes, which are helically locked to a defined twist angle by tethers of different lengths. Ultrafast transient absorption and time resolved fluorescence show a clear dependence of the rate of intersystem crossing with twisting. This trend is explained using quantum chemical calculations, showing an increase of spin-orbit coupling (SOC). At much earlier times, structural reorganization in S1, including coherent vibrational wave packet motions, is reflected in transient spectral changes. As predicted by theory, decreasing the length of diagonal tether induces enhanced activity and frequency blue-shifting of a normal vibration consisting of anthracene twisting against restraint of the tethering chain. Overall, these results serve as design principles for tuning photophysical properties of acenes via controlled twisting of their aromatic core.
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Affiliation(s)
- Partha Malakar
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Veniamin Borin
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Anjan Bedi
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Sanford Ruhman
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel.
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11
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Dishi O, Malakar P, Shimon LJW, Ruhman S, Gidron O. Cover Feature: Ring Size Determines the Conformation, Global Aromaticity and Photophysical Properties of Macrocyclic Oligofurans (Chem. Eur. J. 71/2021). Chemistry 2021. [DOI: 10.1002/chem.202104303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Or Dishi
- Institute of Chemistry The Hebrew University of Jerusalem Edmond J. Safra Campus Jerusalem 9190401 Israel
| | - Partha Malakar
- Institute of Chemistry The Hebrew University of Jerusalem Edmond J. Safra Campus Jerusalem 9190401 Israel
| | - Linda J. W. Shimon
- Chemical Research Support Unit Weizmann Institute of Science Rehovot 7610001 Israel
| | - Sanford Ruhman
- Institute of Chemistry The Hebrew University of Jerusalem Edmond J. Safra Campus Jerusalem 9190401 Israel
| | - Ori Gidron
- Institute of Chemistry The Hebrew University of Jerusalem Edmond J. Safra Campus Jerusalem 9190401 Israel
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12
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Dishi O, Malakar P, Shimon LJW, Ruhman S, Gidron O. Ring Size Determines the Conformation, Global Aromaticity and Photophysical Properties of Macrocyclic Oligofurans. Chemistry 2021; 27:17794-17801. [PMID: 34747542 DOI: 10.1002/chem.202103536] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Indexed: 11/09/2022]
Abstract
In π-conjugated macrocycles, there is a trade-off between the global and local expression of effects such as aromaticity, with the outcome of the trade-off determined by the geometry and aromaticity of the constituent units. Compared with other aromatic rings, the aromatic character of furan is relatively small, and therefore global effects in macrocyclic furans are expected to be more pronounced. Following our introduction of macrocyclic oligofuran, we present the first synthesis of a series of π-conjugated bifuran macrocycles of various ring sizes, from trimer to hexamer, and characterize them using both computational and experimental methods. The properties of macrocyclic oligofurans change considerably with size: The smaller trimer is rigid, weakly emissive and planar as revealed by its single crystal structure, and displays global antiaromaticity. In contrast, the larger pentamer and hexamer are flexible, emissive, have non-planar structures, and exhibit local aromaticity. The results are supported by NICS and ACID calculations that indicate the global antiaromaticity of planar furan macrocycles, and by transient absorption measurements showing sharp absorption band for the trimer and only the internal conversion decay pathway.
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Affiliation(s)
- Or Dishi
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Partha Malakar
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Linda J W Shimon
- Chemical Research Support Unit, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Sanford Ruhman
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, 9190401, Israel
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13
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Armon AM, Bedi A, Borin V, Schapiro I, Gidron O. Bending versus Twisting Acenes - A Computational Study. European J Org Chem 2021; 2021:5424-5429. [PMID: 34819798 PMCID: PMC8597036 DOI: 10.1002/ejoc.202100865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/23/2021] [Indexed: 01/07/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are widely used in organic electronic devices. The electronic, magnetic, and optical properties of PAHs can be tuned by structural modifications to the aromatic backbone to introduce an inherent distortion from planarity, such as bending or twisting. However, it remains difficult to isolate and control the effects of such distortions. Here, we sought to understand how backbone twisting and bending affect the electronic properties of acenes, as models for larger PAHs. We found that, even when highly distorted from planarity (30° per ring), acenes maintain their aromatic character and π orbital delocalization with minor mixing of the σ and π orbitals. In addition, the energy gap between the HOMO and LUMO decreases with increasing twist, while the gap is hardly affected by bending, since the energy of both orbitals increase to a similar extent. For bent acenes in the triplet state, the spin becomes more localized with increasing bend, whereas twisting produces an evenly distributed spin delocalization. These findings can guide the synthesis of PAHs with tailored properties.
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Affiliation(s)
- Amit Manor Armon
- Institute of ChemistryThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Anjan Bedi
- Institute of ChemistryThe Hebrew University of JerusalemJerusalem9190401Israel
- Department of ChemistrySRM Institute of Science and TechnologyKattankulathur603203Tamil NaduIndia
| | - Veniamin Borin
- Fritz Haber Center for Molecular Dynamics ResearchInstitute of ChemistryThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics ResearchInstitute of ChemistryThe Hebrew University of JerusalemJerusalem9190401Israel
| | - Ori Gidron
- Institute of ChemistryThe Hebrew University of JerusalemJerusalem9190401Israel
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14
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Palomo L, Gordillo Gámez F, Bedi A, Gidron O, Casado J, Ramírez FJ. Raman and ROA analyses of twisted anthracenes: connecting vibrational and electronic/photonic structures. Phys Chem Chem Phys 2021; 23:13996-14003. [PMID: 34151326 PMCID: PMC8246141 DOI: 10.1039/d1cp01505b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/30/2021] [Indexed: 11/25/2022]
Abstract
In this article the Raman and Raman Optical Activity (ROA) spectra of a series of enantiomeric twisted anthracenes are presented. The evolution of their vibrational spectra is understood in the context of the variation of π-electron delocalization as a result of the twisting imparted by the belt structure and in terms of the modulation of the resonance Raman/ROA effects which are photonic properties also tuned by anthracene twisting. The Raman/ROA vibrational spectra are simulated by several theoretical approaches to account for their vibrational and electronic properties including the theoretical evaluation of resonance effects. We furthermore incorporate a vibrational and ROA activity dissection analysis as provided in the Pyvib2 program valid to establish correlations among vibrational modes of different molecules with different electronic structures and equivalent vibrational dynamics. This paper is one of the very first attempts to use ROA spectroscopy in π-conjugated molecules with twisted and helical morphologies that contrast with the well-known cases of ROA studies of chiral helicenes in which the impact of π-electron delocalization in the electronic/photonic/vibrational (Raman/ROA) spectra is negligible.
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Affiliation(s)
- Luis Palomo
- Departamento de Química Física, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain.
| | - Fernando Gordillo Gámez
- Departamento de Química Física, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain.
| | - Anjan Bedi
- Institute of Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel and Department of Chemistry, SRM Institute of Science and Technolog, Kattankulathur 603203, Tamil Nadu, India
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Juan Casado
- Departamento de Química Física, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain.
| | - Francisco J Ramírez
- Departamento de Química Física, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain.
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15
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Amsallem D, Bedi A, Tassinari F, Gidron O. Relation between Morphology and Chiroptical Properties in Chiral Conducting Polymer Films: A Case Study in Chiral PEDOT. Macromolecules 2020; 53:9521-9528. [PMID: 33191953 PMCID: PMC7660938 DOI: 10.1021/acs.macromol.0c01731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 10/07/2020] [Indexed: 11/28/2022]
Abstract
The electronic properties of conducting polymers are influenced by their micro- and macrostructural orders, which can be tailored by substituent modification. However, while the effect of substituents on conducting polymers is extensively investigated, chiral substituents are far less studied. Furthermore, many chiral conducting polymers have regioirregular structures, which result in polymer films with inferior properties. In this work, we apply electronic circular dichroism (ECD) spectroscopy to study the morphological changes to the chiral polymers under different polymerization conditions. For this purpose, we investigated 3,4-ethylenedioxythiophene (EDOT) derivatives having two stereogenic centers on each monomer and bearing methyl or phenyl side groups (dimethyl-EDOT and diphenyl-EDOT, respectively). Polymerizing the enantiomerically pure monomers produces regioregular and stereoregular dimethyl-PEDOT and diphenyl-PEDOT, respectively. The effect of the electrolyte and solvent on polymer film morphology was studied using scanning electron microscopy (SEM) and ECD, showing a correlation between the polymer's morphology and the chiroptical properties of its films. We found that, for diphenyl-PEDOT, the combination of perchlorate anion electrolyte and acetonitrile solvent resulted in a unique morphology characterized by significant intermolecular interactions. These interactions were clearly observable in the ECD spectra in the form of exciton couplings, whose presence was supported by TD-DFT calculations. A small enantiomeric excess was sufficient to induce very intense ECD signals, demonstrating chiral amplification in electropolymerized films.
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Affiliation(s)
- Dana Amsallem
- The
Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 9190401 Jerusalem, Israel
| | - Anjan Bedi
- The
Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 9190401 Jerusalem, Israel
| | - Francesco Tassinari
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, 76100 Rehovot, Israel
| | - Ori Gidron
- The
Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 9190401 Jerusalem, Israel
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16
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Abstract
![]()
The use of polyaromatic hydrocarbons
to capture and release singlet oxygen is of considerable importance
in materials chemistry, synthesis, and photodynamic therapy. Here
we studied the ability of a series of tethered twistacenes, possessing
different degrees of backbone twist, to capture and release singlet
oxygen via the reversible Diels–Alder reaction. When the twistacene
acts as both a sensitizer and a diene, the photo-oxidation rate depends
on the extinction coefficient of the irradiation wavelength. However,
when the twistacenes function solely as a diene, the rate of photo-oxidation
increases with increasing twist. The rate of the reverse reaction,
the singlet oxygen release, also increases with increasing twist.
The calculated transition state energy decreases with increasing twist,
which can explain the observed trend. The presence of the tether significantly
increases the reversibility of the reaction, which can proceed in
repeated forward and reverse cycles in very high yield under mild
conditions, as required for molecular switches.
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Affiliation(s)
- Anjan Bedi
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Amit Manor Armon
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
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17
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Mulay SV, Dishi O, Fang Y, Niazi MR, Shimon LJW, Perepichka DF, Gidron O. A macrocyclic oligofuran: synthesis, solid state structure and electronic properties. Chem Sci 2019; 10:8527-8532. [PMID: 32055302 PMCID: PMC7003964 DOI: 10.1039/c9sc03247a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/19/2019] [Indexed: 11/27/2022] Open
Abstract
The first π-conjugated macrocyclic system with an oligofuran backbone display planar conformation and forms large π-aggregates, in contrast to the twisted conformation of small macrocyclic oligothiophenes.
We report the first π-conjugated macrocyclic system with an oligofuran backbone. The calculated HOMO–LUMO gap is similar to that of the corresponding linear polymer, indicating a remarkable electron delocalization. The X-ray structure reveals a planar conformation, in contrast to the twisted conformation of macrocyclic oligothiophenes. The intermolecular π–π stacking distance is extremely small (3.17 Å), indicating very strong interactions. The macrocycle forms large π-aggregates in solution and shows a tendency toward highly ordered multilayer adsorption at the solid–liquid interface. The face-on orientation of molecules explains the higher hole mobility observed in the out-of-plane direction.
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Affiliation(s)
- Sandip V Mulay
- Institute of Chemistry , The Hebrew University of Jerusalem , Edmond J. Safra Campus , Jerusalem , Israel .
| | - Or Dishi
- Institute of Chemistry , The Hebrew University of Jerusalem , Edmond J. Safra Campus , Jerusalem , Israel .
| | - Yuan Fang
- Department of Chemistry , McGill University , Montreal , QC H3A 0B8 , Canada .
| | - Muhammad R Niazi
- Department of Chemistry , McGill University , Montreal , QC H3A 0B8 , Canada .
| | - Linda J W Shimon
- Chemical Research Support Unit , Weizmann Institute of Science , Rehovot , Israel
| | | | - Ori Gidron
- Institute of Chemistry , The Hebrew University of Jerusalem , Edmond J. Safra Campus , Jerusalem , Israel .
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18
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Tait CE, Bedi A, Gidron O, Behrends J. Photoexcited triplet states of twisted acenes investigated by Electron Paramagnetic Resonance. Phys Chem Chem Phys 2019; 21:21588-21595. [PMID: 31539003 DOI: 10.1039/c9cp04135d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Twisting of the acene backbone out of planarity in twisted acenes leads to a variation in their optical and electronic properties. The effect of increasing twist angles on the properties of the photoexcited triplet states of a series of anthracene-based helically tethered twisted acenes is investigated here by Electron Paramagnetic Resonance (EPR) spectroscopy. Increasing signal intensities with increasing twist angles indicate increased intersystem crossing efficiencies for the twisted molecules compared to the untethered reference compound. Variations in the electron spin polarisation observed in the transient EPR spectra, in particular for the compound with the shortest tether, imply changes in the sublevel population kinetics depending on molecular geometry. Changes in the zero-field splitting parameters and in the proton hyperfine couplings for compounds with short tethers and therefore higher twist angles point towards a slight redistribution of the spin density compared to the parent compound. The experimental results can be explained by considering both an increase in twist angle and a related decrease in the dihedral angle between the phenyl side groups and the acene core. The observation of a clear excitation-wavelength dependence suggests preferential excitation of different molecular conformations, with conformers characterised by higher twist angles selected at higher wavelengths.
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Affiliation(s)
- Claudia E Tait
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
| | - Anjan Bedi
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Jan Behrends
- Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
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Abstract
The properties of polycyclic aromatic hydrocarbons are determined by their size, shape, and functional groups. Equally important is their curvature, since deviation from planarity can affect their optical, electronic, and magnetic properties and also induce chirality. Acenes, which can be viewed as one-dimensional nanocarbons, are often twisted out of planarity. Although twisting is expected to affect the above-mentioned properties, it is often overlooked. This Account focuses on helically locked twistacenes (twisted acenes) having different twist angles and the effect of twisting on their electronic and optical properties. Various synthetic approaches to inducing backbone twist in acenes are discussed, with a focus on the introduction of a diagonal tether across the core, as this minimizes confounding substituent effects. Using such tethered acenes as our model, we then discuss the effects of twisting the aromatic core on twistacene properties. Electronic properties. Increasing the degree of twist only slightly affects the HOMO and LUMO energy levels. Twisting leads to a small increase in the HOMO level and a decrease in the LUMO level, which produces an overall decrease in the HOMO-LUMO gap. Optical properties. As the degree of twist increases, a slight bathochromic shift is observed in the absorption spectra, in accordance with the decrease in the HOMO-LUMO gap. The fluorescence quantum efficiency and the fluorescence lifetime also decrease. This is likely to be related to an increasing rate of intersystem crossing, which arises from increased spin-orbit coupling. In addition, computational studies indicate that the S0-T1 energy gap decreases with increasing twist. Chiroptical properties. Increased twisting results in a larger Cotton effect and anisotropy factor, with the anisotropy factors of Ant-Cn being higher than those of longer helicenes. The parallel orientation of electric and magnetic transition dipole moments in twistacenes underlies this behavior and renders them as excellent chiroptical materials. The same trend is observed for the radical cations of twistacenes, which absorb in the NIR spectral region. Conjugation and delocalization. Twisting the anthracene radical cation up to 40° (13° per benzene ring) does not significantly affect spin delocalization, with the EPR spectra of twistacene radical cations showing that only slight localization occurs. This is in line with computational studies, which show only a small decrease in π-overlap for large acene twist. Overall, modifying the length of the tether in diagonally tethered acenes allows chemists to control core twist and to induce chirality. Twisting affects key optical, electronic, and chiroptical properties of acenes. Consequently, controlling the twist angle can improve the future design of nanocarbons with desired properties.
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Affiliation(s)
- Anjan Bedi
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel
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20
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Luo GF, Biniuri Y, Chen WH, Neumann E, Fadeev M, Marjault HB, Bedi A, Gidron O, Nechushtai R, Stone D, Happe T, Willner I. Artificial Photosynthesis with Electron Acceptor/Photosensitizer-Aptamer Conjugates. Nano Lett 2019; 19:6621-6628. [PMID: 31407917 DOI: 10.1021/acs.nanolett.9b02880] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sequence-specific aptamers act as functional scaffolds for the assembly of photosynthetic model systems. The Ru(II)-tris-bipyridine photosensitizer is conjugated by different binding modes to the antityrosinamide aptamer to yield a set of photosensitizer-aptamer binding scaffolds. The N-methyl-N'-(3-aminopropane)-4,4'-bipyridinium electron acceptor, MV2+, is covalently linked to tyrosinamide, TA, to yield the conjugate TA-MV2+. The tyrosinamide unit in TA-MV2+ acts as a ligand for anchoring TA-MV2+ to the Ru(II)-tris-bipyridine-aptamer scaffold, generating the diversity of photosensitizer-aptamer/electron acceptor supramolecular conjugates. Effective electron transfer quenching in the photosynthetic model systems is demonstrated, and the quenching efficiencies are controlled by the structural features of the conjugates. The redox species generated by the photosensitizer-aptamer/electron acceptor supramolecular systems mediate the ferredoxin-NADP+ reductase, FNR, catalyzed synthesis of NADPH, and the Pt-nanoparticle-catalyzed evolution of hydrogen (H2). The novelty of the study rests on the unprecedented use of aptamer scaffolds as functional units for organizing photosynthetic model systems.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Thomas Happe
- Fakultät für Biologie und Biotechnologie, AG Photobiotechnologie , Ruhr Universität Bochum , Universitätsstraße 150 , 44801 Bochum , Germany
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21
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Abstract
We introduce the first series of enantiopure twistacene radical cations, which form reversibly upon chemical or electrochemical oxidation. Their vis-NIR chiroptical properties (Cotton effect and anisotropy factor) increase systematically with the backbone twist. The hyperfine constants observed by EPR demonstrate significant spin delocalization even for large backbone twist angles.
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Affiliation(s)
- Anjan Bedi
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel.
| | - Raanan Carmieli
- Chemical Research Support Unit, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel.
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22
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Affiliation(s)
- Hadar R. Yakir
- Institute of ChemistryThe Hebrew University of Jerusalem, Edmond J. Safra Campus Jerusalem 91904 Israel
| | - Linda J. W. Shimon
- Chemical Research Support UnitWeizmann Institute of Science Rehovot 76100 Israel
| | - Ori Gidron
- Institute of ChemistryThe Hebrew University of Jerusalem, Edmond J. Safra Campus Jerusalem 91904 Israel
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23
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Bedi A, Gidron O. Front Cover: Chiroptical Properties of Twisted Acenes: Experimental and Computational Study (Chem. Eur. J. 13/2019). Chemistry 2019. [DOI: 10.1002/chem.201900301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Anjan Bedi
- Institute of Chemistry; The Hebrew University of Jerusalem; Edmond J. Safra Campus Jerusalem Israel
| | - Ori Gidron
- Institute of Chemistry; The Hebrew University of Jerusalem; Edmond J. Safra Campus Jerusalem Israel
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24
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Abstract
Acenes that are twisted out of planarity are expected to display chiroptical properties. However, the effect of twisting on the chiroptical properties of acenes has not been investigated computationally or experimentally. Herein, we present a computational investigation of the chiroptical properties of anthracenes to pentacenes, combined with an experimental study using a series of helically locked acenes, twisted to different torsional angles in their enantiopure form. The lowest energy transition, which is relatively weak in acenes, becomes dominant in their circular dichroism spectra upon twisting. We find that the rotational strength of acenes consistently increases with increasing twist. The experimental data obtained from enantiopure tethered twistacenes show the same trend as the calculated result, with a strong Cotton effect and anisotropy factor, rendering twisted acenes as excellent chiroptical materials.
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Affiliation(s)
- Anjan Bedi
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem, Israel
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25
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Bedi A, Gidron O. Chiroptical Properties of Twisted Acenes: Experimental and Computational Study. Chemistry 2019. [DOI: 10.1002/chem.201900302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Anjan Bedi
- Institute of ChemistryThe Hebrew University of Jerusalem Edmond J. Safra Campus Jerusalem Israel
| | - Ori Gidron
- Institute of ChemistryThe Hebrew University of Jerusalem Edmond J. Safra Campus Jerusalem Israel
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26
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Abstract
π-Conjugated molecules are the active materials in organic electronics, yet the range of available materials is limited by the nontrivial, multistep synthetic process required to obtain long π-conjugated backbones. Here, Diels–Alder cycloaddition and its reactivity and selectivity are evaluated as a means for obtaining long, novel, π-conjugated backbones. Particular attention is paid to the Diels–Alder conjugation products of furans, such as selectively substituted arenes and, potentially, carbon nanoribbons.1 Introduction2 Aromatic Transformations by Diels–Alder Cycloaddition3 The Question of Regioselectivity4 Outlook
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Affiliation(s)
- Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem
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27
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Abstract
Twisting linear acenes out of planarity affects their electronic and optical properties, and induces chirality. However, it is difficult to isolate the effect of twisting from the substituent effect. Moreover, many twistacenes (twisted acenes) readily racemize in solution. Here, we introduce a series of twistacenes having an anthracene backbone diagonally tethered by an n-alkyl bridge, which induces a twist of various angles. This allows us to systematically monitor the effect of twisting on electronic and optical properties. We find that absorption is bathochromically shifted with increasing twist, while fluorescence quantum efficiency drops dramatically. The tethered twistacenes were isolated to their enantiomerically pure form, displaying strong chiroptical properties and anisotropy factor ( g-value). No racemization was observed even upon prolonged heating, rendering these tethered twistacenes suitable as enantiopure helical building units for π-conjugated backbones.
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Affiliation(s)
- Anjan Bedi
- Institute of Chemistry , The Hebrew University of Jerusalem, Edmond J. Safra Campus , Jerusalem 91904 , Israel
| | - Linda J W Shimon
- Chemical Research Support Unit , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Ori Gidron
- Institute of Chemistry , The Hebrew University of Jerusalem, Edmond J. Safra Campus , Jerusalem 91904 , Israel
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28
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Affiliation(s)
- Or Dishi
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
| | - Ori Gidron
- Institute of Chemistry, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 91904, Israel
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29
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Affiliation(s)
- Sunita Gadakh
- Institute of Chemistry; The Hebrew University of Jerusalem; Edmond J. Safra Campus Jerusalem Israel
| | - Linda J. W. Shimon
- Chemical Research Support Unit; Weizmann Institute of Science; Rehovot 7610001 Israel
| | - Ori Gidron
- Institute of Chemistry; The Hebrew University of Jerusalem; Edmond J. Safra Campus Jerusalem Israel
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30
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Gadakh S, Shimon LJW, Gidron O. Regioselective Transformation of Long π-Conjugated Backbones: From Oligofurans to Oligoarenes. Angew Chem Int Ed Engl 2017; 56:13601-13605. [DOI: 10.1002/anie.201705914] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Sunita Gadakh
- Institute of Chemistry; The Hebrew University of Jerusalem; Edmond J. Safra Campus Jerusalem Israel
| | - Linda J. W. Shimon
- Chemical Research Support Unit; Weizmann Institute of Science; Rehovot 7610001 Israel
| | - Ori Gidron
- Institute of Chemistry; The Hebrew University of Jerusalem; Edmond J. Safra Campus Jerusalem Israel
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31
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Gidron O, Jirásek M, Wörle M, Diederich F. Enantiopure Alleno-Acetylenic Helicages Containing Multiple Binding Sites. Chemistry 2016; 22:16172-16177. [DOI: 10.1002/chem.201603923] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Ori Gidron
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
- The Institute of Chemistry; The Hebrew University of Jerusalem; Edmond J. Safra, Givat Ram Jerusalem 91904 Israel
| | - Michael Jirásek
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
| | - Michael Wörle
- Laboratorium für Anorganische Chemie; ETH Zurich; Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - François Diederich
- Laboratorium für Organische Chemie; ETH Zurich; Vladimir-Prelog-Weg 3 8093 Zurich Switzerland
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32
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Zenkina OV, Gidron O, Shimon LJW, Iron MA, van der Boom ME. Mechanistic Aspects of Aryl-Halide Oxidative Addition, Coordination Chemistry, and Ring-Walking by Palladium. Chemistry 2015; 21:16113-25. [PMID: 26382568 DOI: 10.1002/chem.201501580] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/17/2015] [Indexed: 11/07/2022]
Abstract
This contribution describes the reactivity of a zero-valent palladium phosphine complex with substrates that contain both an aryl halide moiety and an unsaturated carbon-carbon bond. Although η(2) -coordination of the metal center to a C=C or C≡C unit is kinetically favored, aryl halide bond activation is favored thermodynamically. These quantitative transformations proceed under mild reaction conditions in solution or in the solid state. Kinetic measurements indicate that formation of η(2) -coordination complexes are not nonproductive side-equilibria, but observable (and in several cases even isolated) intermediates en route to aryl halide bond cleavage. At the same time, DFT calculations show that the reaction with palladium may proceed through a dissociation-oxidative addition mechanism rather than through a haptotropic intramolecular process (i.e., ring walking). Furthermore, the transition state involves coordination of a third phosphine to the palladium center, which is lost during the oxidative addition as the C-halide bond is being broken. Interestingly, selective activation of aryl halides has been demonstrated by adding reactive aryl halides to the η(2) -coordination complexes. The product distribution can be controlled by the concentration of the reactants and/or the presence of excess phosphine.
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Affiliation(s)
- Olena V Zenkina
- Department of Organic Chemistry, The Weizmann Institute of Science, 76100 Rehovot (Israel).,Current address: Faculty of Science, University of Ontario Institute of Technology, Oshawa, ON (Canada)
| | - Ori Gidron
- Department of Organic Chemistry, The Weizmann Institute of Science, 76100 Rehovot (Israel)
| | - Linda J W Shimon
- Department of Chemical Research Support, The Weizmann Institute of Science, 76100 Rehovot (Israel)
| | - Mark A Iron
- Department of Chemical Research Support, The Weizmann Institute of Science, 76100 Rehovot (Israel)
| | - Milko E van der Boom
- Department of Organic Chemistry, The Weizmann Institute of Science, 76100 Rehovot (Israel).
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33
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Gidron O, Jirásek M, Trapp N, Ebert MO, Zhang X, Diederich F. Homochiral [2]Catenane and Bis[2]catenane from Alleno-Acetylenic Helicates - A Highly Selective Narcissistic Self-Sorting Process. J Am Chem Soc 2015; 137:12502-5. [PMID: 26380872 DOI: 10.1021/jacs.5b08649] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Homochiral strands of alternating alleno-acetylenes and phenanthroline ligands (P)-1 and (P2)-2, as well as their corresponding enantiomers, selectively assemble with the addition of silver(I) salt to yield dinuclear and trinuclear double helicates, respectively. Upon increasing the solvent polarity, the dinuclear and trinuclear helicates interlock to form a [2]catenane and bis[2]catenane, bearing 14 chirality elements, respectively. The solid-state structure of the [2]catenane reveals a nearly perfect fit of the interlocked strands, and the ECD spectra show a significant amplification of the chiroptical properties upon catenation, indicating stabilization of the helical secondary structure. Highly selective narcissistic self-sorting was demonstrated for a racemic mixture consisting of both short and long alleno-acetylenic strands, highlighting their potential for the preparation of linear catenanes of higher order.
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Affiliation(s)
- Ori Gidron
- Laboratory of Organic Chemistry, ETH Zurich , Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - Michael Jirásek
- Laboratory of Organic Chemistry, ETH Zurich , Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - Nils Trapp
- Laboratory of Organic Chemistry, ETH Zurich , Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - Marc-Olivier Ebert
- Laboratory of Organic Chemistry, ETH Zurich , Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - Xiangyang Zhang
- Laboratory of Organic Chemistry, ETH Zurich , Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
| | - François Diederich
- Laboratory of Organic Chemistry, ETH Zurich , Vladimir-Prelog-Weg 3, CH-8093 Zurich, Switzerland
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Sheberla D, Patra S, Wijsboom YH, Sharma S, Sheynin Y, Haj-Yahia AE, Barak AH, Gidron O, Bendikov M. Conducting polyfurans by electropolymerization of oligofurans. Chem Sci 2015; 6:360-371. [PMID: 28966762 PMCID: PMC5586207 DOI: 10.1039/c4sc02664k] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Accepted: 10/03/2014] [Indexed: 11/28/2022] Open
Abstract
Polyfuran films produced by electropolymerization of a series of oligofurans substituted with alkyl groups show improved properties, such as good conductivity and stability, well-defined spectroelectrochemistry and smooth morphology.
Polyfurans have never been established as useful conjugated polymers, as previously they were considered to be inherently unstable and poorly conductive. Here, we show the preparation of stable and conducting polyfuran films by electropolymerization of a series of oligofurans of different chain lengths substituted with alkyl groups. The polyfuran films show good conductivity in the order of 1 S cm–1, good environmental and electrochemical stabilities, very smooth morphologies (roughness 1–5 nm), long effective conjugation lengths, well-defined spectroelectrochemistry and electro-optical switching (in the Vis-NIR region), and have optical band-gaps in the range of 2.2–2.3 eV. A low oxidation potential needed for polymerization of oligofurans (compared to furan) is a key factor in achievement of improved properties of polyfurans reported in this work. DFT calculations and experiments show that polyfurans are much more rigid than polythiophenes, and alkyl substitution does not disturb backbone planarity and conjugation. The obtained properties of polyfuran films are similar or superior to the properties of electrochemically prepared poly(oligothiophene)s under similar conditions.
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Affiliation(s)
- Dennis Sheberla
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
| | - Snehangshu Patra
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
| | - Yair H Wijsboom
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
| | - Sagar Sharma
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
| | - Yana Sheynin
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
| | - Abd-Elrazek Haj-Yahia
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
| | - Adva Hayoun Barak
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
| | - Ori Gidron
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
| | - Michael Bendikov
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , 76100 , Israel
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Gidron O, Ebert MO, Trapp N, Diederich F. Chiroptical Detection of Nonchromophoric, Achiral Guests by Enantiopure Alleno-Acetylenic Helicages. Angew Chem Int Ed Engl 2014; 53:13614-8. [DOI: 10.1002/anie.201406585] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/24/2014] [Indexed: 11/12/2022]
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Gidron O, Ebert MO, Trapp N, Diederich F. Chiroptische Detektion achiraler Gäste ohne Chromophor durch enantiomerenreine alleno-acetylenische helicale Käfige. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201406585] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Donckele EJ, Gidron O, Trapp N, Diederich F. Outstanding Chiroptical Properties: A Signature of Enantiomerically Pure Alleno-Acetylenic Macrocycles and Monodisperse Acyclic Oligomers. Chemistry 2014; 20:9558-66. [DOI: 10.1002/chem.201402758] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Indexed: 02/01/2023]
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Gidron O, Bendikov M. α-Oligofurans: An Emerging Class of Conjugated Oligomers for Organic Electronics. Angew Chem Int Ed Engl 2014; 53:2546-55. [DOI: 10.1002/anie.201308216] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Indexed: 11/09/2022]
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Gidron O, Diskin-Posner Y, Bendikov M. High Charge Delocalization and Conjugation in Oligofuran Molecular Wires. Chemistry 2013; 19:13140-50. [DOI: 10.1002/chem.201301293] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Indexed: 11/08/2022]
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Hayoun Barak A, de Ruiter G, Lahav M, Sharma S, Gidron O, Evmenenko G, Dutta P, Bendikov M, van der Boom ME. Coordination-Based Molecular Assemblies of Oligofurans and Oligothiophenes. Chemistry 2013; 19:8821-31. [DOI: 10.1002/chem.201300034] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Indexed: 11/11/2022]
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Gidron O, Varsano N, Shimon LJW, Leitus G, Bendikov M. Study of a bifuran vs. bithiophene unit for the rational design of π-conjugated systems. What have we learned? Chem Commun (Camb) 2013; 49:6256-8. [DOI: 10.1039/c3cc41795f] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Gidron O, Shimon LJW, Leitus G, Bendikov M. Reactivity of Long Conjugated Systems: Selectivity of Diels–Alder Cycloaddition in Oligofurans. Org Lett 2012; 14:502-5. [DOI: 10.1021/ol202987e] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ori Gidron
- Department of Organic Chemistry and Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Linda J. W. Shimon
- Department of Organic Chemistry and Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Gregory Leitus
- Department of Organic Chemistry and Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Michael Bendikov
- Department of Organic Chemistry and Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 76100, Israel
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Ferrón CC, Delgado MCR, Gidron O, Sharma S, Sheberla D, Sheynin Y, Bendikov M, Navarrete JTL, Hernández V. α-Oligofurans show a sizeable extent of π-conjugation as probed by Raman spectroscopy. Chem Commun (Camb) 2012; 48:6732-4. [DOI: 10.1039/c2cc18144d] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Gidron O, Dadvand A, Sheynin Y, Bendikov M, Perepichka DF. Towards “green” electronic materials. α-Oligofurans as semiconductors. Chem Commun (Camb) 2011; 47:1976-8. [DOI: 10.1039/c0cc04699j] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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