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Fukuda H, Tsurumaki E, Wakamatsu K, Toyota S. Unusually Short H⋅⋅⋅H Contacts in Intramolecularly Cyclized Helically Fused Anthracenes. Chemistry 2024:e202401627. [PMID: 38751350 DOI: 10.1002/chem.202401627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Indexed: 06/27/2024]
Abstract
The intramolecular coupling of dichloro-substituted helically fused anthracenes using the Yamamoto coupling yielded cyclized products with sterically congested molecular structures. The X-ray analysis and DFT calculations showed that the aromatic framework adopted a nonplanar structure with a twisted conformation about the newly formed single bond, which acts as a chiral axis. Interestingly, the X-ray structure obtained through the Hirshfeld atom refinement revealed short interatomic distances between the inner hydrogen atoms (1.648-1.692 Å), much shorter than the sum of their van der Waals radii. Owing to these unusually short contacts, the 1H NMR spectrum exhibited a significant deshielding (12.5 ppm) and a large nuclear Overhauser effect (44 %). Additionally, the IR spectrum displayed a high-frequency shift of the C-H stretching vibration. These observations, along with the noncovalent interaction plot indicative of a characteristic steric environment, strongly support the presence of steric hindrance. Moreover, dynamic NMR measurement of the mesityl-substituted derivative yielded a barrier to helical inversion of 84 kJ mol-1. The optical properties and crystal packing of the cyclized products are also reported.
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Affiliation(s)
- Hiroki Fukuda
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Eiji Tsurumaki
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Kan Wakamatsu
- Department of Chemistry, Faculty of Science, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama, 700-0005, Japan
| | - Shinji Toyota
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
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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] [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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Porsev VV, Evarestov RA. Current State of Computational Modeling of Nanohelicenes. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2295. [PMID: 37630880 PMCID: PMC10458037 DOI: 10.3390/nano13162295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023]
Abstract
This review considers the works that focus on various aspects of the theoretical description of nanohelicenes (other equivalent names are graphene spirals, graphene helicoid, helical graphene nanoribbon, or helical graphene)-a promising class of one-dimensional nanostructures. The intrinsic helical topology and continuous π-system lead to the manifestation of unique optical, electronic, and magnetic properties that are also highly dependent on axial and torsion strains. In this paper, it was shown that the properties of nanohelicenes are mainly associated with the peripheral modification of the nanohelicene ribbon. We have proposed a nomenclature that enables the classification of all nanohelicenes as modifications of some prototype classes.
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Affiliation(s)
- Vitaly V. Porsev
- Quantum Chemistry Department, Saint-Petersburg State University, St Petersburg 199034, Russia
| | - Robert A. Evarestov
- Quantum Chemistry Department, Saint-Petersburg State University, St Petersburg 199034, Russia
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Bloch WM, Horiuchi S, Holstein JJ, Drechsler C, Wuttke A, Hiller W, Mata RA, Clever GH. Maximized axial helicity in a Pd 2L 4 cage: inverse guest size-dependent compression and mesocate isomerism. Chem Sci 2023; 14:1524-1531. [PMID: 36794203 PMCID: PMC9906678 DOI: 10.1039/d2sc06629g] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 01/12/2023] [Indexed: 01/21/2023] Open
Abstract
Helicity is an archetypal structural motif of many biological systems and provides a basis for molecular recognition in DNA. Whilst artificial supramolecular hosts are often helical, the relationship between helicity and guest encapsulation is not well understood. We report a detailed study on a significantly coiled-up Pd2L4 metallohelicate with an unusually wide azimuthal angle (∼176°). Through a combination of NMR spectroscopy, single-crystal X-ray diffraction, trapped ion mobility mass spectrometry and isothermal titration calorimetry we show that the coiled-up cage exhibits extremely tight anion binding (K of up to 106 M-1) by virtue of a pronounced oblate/prolate cavity expansion, whereby the Pd-Pd separation decreases for mono-anionic guests of increasing size. Electronic structure calculations point toward strong dispersion forces contributing to these host-guest interactions. In the absence of a suitable guest, the helical cage exists in equilibrium with a well-defined mesocate isomer that possesses a distinct cavity environment afforded by a doubled Pd-Pd separation distance.
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Affiliation(s)
- Witold M. Bloch
- Department of Chemistry and Chemical Biology, TU Dortmund UniversityOtto-Hahn-Straße 644227 DortmundGermany,Institute for Nanoscale Science and Technology, College of Science and Engineering, Flinders UniversityAdelaideSouth Australia 5042Australia
| | - Shinnosuke Horiuchi
- Department of Chemistry and Chemical Biology, TU Dortmund University Otto-Hahn-Straße 6 44227 Dortmund Germany .,Division of Chemistry and Materials Science, Graduate School of Engineering, Nagasaki University Bunkyo-machi Nagasaki 852-8521 Japan
| | - Julian J. Holstein
- Department of Chemistry and Chemical Biology, TU Dortmund UniversityOtto-Hahn-Straße 644227 DortmundGermany
| | - Christoph Drechsler
- Department of Chemistry and Chemical Biology, TU Dortmund University Otto-Hahn-Straße 6 44227 Dortmund Germany
| | - Axel Wuttke
- Institute of Physical Chemistry, Georg-August University GöttingenTammannstraße 637077 GöttingenGermany
| | - Wolf Hiller
- Department of Chemistry and Chemical Biology, TU Dortmund University Otto-Hahn-Straße 6 44227 Dortmund Germany
| | - Ricardo A. Mata
- Institute of Physical Chemistry, Georg-August University GöttingenTammannstraße 637077 GöttingenGermany
| | - Guido H. Clever
- Department of Chemistry and Chemical Biology, TU Dortmund UniversityOtto-Hahn-Straße 644227 DortmundGermany
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Suzuki K, Fukuda H, Toda H, Imai Y, Nojima Y, Hasegawa M, Tsurumaki E, Toyota S. Substituent effects on helical structures and chiroptical properties of fused anthracenes with bulky phenyl groups. Tetrahedron 2023. [DOI: 10.1016/j.tet.2022.133243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Kiel GR, Bergman HM, Samkian AE, Schuster NJ, Handford RC, Rothenberger AJ, Gomez-Bombarelli R, Nuckolls C, Tilley TD. Expanded [23]-Helicene with Exceptional Chiroptical Properties via an Iterative Ring-Fusion Strategy. J Am Chem Soc 2022; 144:23421-23427. [PMID: 36525313 DOI: 10.1021/jacs.2c09555] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Expanded helicenes are an emerging class of helical nanocarbons composed of alternating linear and angularly fused rings, which give rise to an internal cavity and a large diameter. The latter is expected to impart exceptional chiroptical properties, but low enantiomerization free energy barriers (ΔG‡e) have largely precluded experimental interrogation of this prediction. Here, we report the syntheses of expanded helicenes containing 15, 19, and 23 rings on the inner helical circuit, using two iterations of an Ir-catalyzed, site-selective [2 + 2 + 2] reaction. This series of compounds displays a linear relationship between the number of rings and ΔG‡e. The expanded [23]-helicene, which is 7 rings longer than any known single carbohelicene and among the longest known all-carbon ladder oligomers, exhibits a ΔG‡e that is high enough (29.2 ± 0.1 kcal/mol at 100 °C in o-DCB) to halt enantiomerization at ambient temperature. This enabled the isolation of enantiopure samples displaying circular dichroism dissymmetry factors of ±0.056 at 428 nm, which are ≥1.7× larger than values for previously reported classical and expanded helicenes. Computational investigations suggest that this improved performance is the result of both the increased diameter and length of the [23]-helicene, providing guiding design principles for high dissymmetry molecular materials.
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Affiliation(s)
- Gavin R Kiel
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Harrison M Bergman
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Adrian E Samkian
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Nathaniel J Schuster
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Rex C Handford
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - August J Rothenberger
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Rafael Gomez-Bombarelli
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Colin Nuckolls
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - T Don Tilley
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
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Li R, Ma B, He RY, Zhang B, Zhang YK, Feng SY, An P. Azepine- or Oxepine-embedded Double Saddle-Helix Nanographenes. Chem Asian J 2021; 17:e202101365. [PMID: 34904381 DOI: 10.1002/asia.202101365] [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: 12/08/2021] [Indexed: 11/09/2022]
Abstract
The azepine- and oxepine-embedded polycyclic aromatic hydrocarbons (PAH) 1-3, as the hexa-peri-hexabenzocoronene (HBC)-based nanographenes (NG) were designed and synthesized by Diels-Alder reaction of cyclic alkene with tetrachlorothiophene-S,S-dioxide, followed by Suzuki-Miyaura cross-coupling and Scholl-type cyclodehydrogenation. Due to the strained seven-membered ring and the inherent structural pattern, heteroatom-doped NGs 1-3 show Cs symmetrical, double saddle-helix hybrid conformation, which represents a new shape for HBC based nanographenes. The calculation studies reveal the low aromaticity of the 8π heterocycles themselves and the heterocycles also decrease the electron delocalization of benzenes surrounding them. Dynamics-based calculation suggests the Cs symmetry would maintain druing the saddle-inversion process. Meanwhile, we show property perturbation by doping with different heteroatoms.
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Affiliation(s)
- Ranran Li
- School of Chemical Science and Technology, Ynunan University, Kunming, 650500, P. R. China
| | - Bin Ma
- School of Chemical Science and Technology, Ynunan University, Kunming, 650500, P. R. China
| | - Run-Ying He
- School of Chemical Science and Technology, Ynunan University, Kunming, 650500, P. R. China
| | - Bin Zhang
- School of Chemical Science and Technology, Ynunan University, Kunming, 650500, P. R. China
| | - Yi-Kang Zhang
- School of Chemical Science and Technology, Ynunan University, Kunming, 650500, P. R. China
| | - Shi-Yu Feng
- School of Chemical Science and Technology, Ynunan University, Kunming, 650500, P. R. China
| | - Peng An
- School of Chemical Science and Technology, Ynunan University, Kunming, 650500, P. R. China
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