1
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Yu Y, Wang C, Hung FF, Chen C, Pan D, Che CM, Liu J. Benzo-Extended Heli(aminoborane)s: Inner Rim BN-Doped Helical Molecular Carbons with Remarkable Chiroptical Properties. J Am Chem Soc 2024. [PMID: 39101597 DOI: 10.1021/jacs.4c06997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Atomically precise synthesis of three-dimensional boron-nitrogen (BN)-based helical structures constitutes an undeveloped field with challenges in synthetic chemistry. Herein, we synthesized and comprehensively characterized a new class of helical molecular carbons, named benzo-extended [n]heli(aminoborane)s ([n]HABs), in which the helical structures consisted of n = 8 and n = 10 ortho-condensed conjugated rings with alternating BN atoms at the inner rims. X-ray crystallographic analysis, photophysical studies, and density functional theory calculations revealed the unique characteristics of this novel [n]HAB system. Owing to the high enantiomerization energy barriers, the optical resolution of [8]HAB and [10]HAB was achieved with chiral high-performance liquid chromatography. The isolated enantiomers of [10]HAB exhibited record absorption and luminescence dissymmetry factors (|gabs|=0.061; |glum|=0.048), and boosted CPL brightness up to 292 M-1 cm-1, surpassing most helicene derivatives, demonstrating that the introduction of BN atoms into the inner positions of helicenes can increase both the |gabs| and |glum| values.
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Affiliation(s)
- Yang Yu
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong 999077, PR China
| | - Chang Wang
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong 999077, PR China
| | - Faan-Fung Hung
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong 999077, PR China
| | - Chen Chen
- Department of Physics and Department of Chemistry, The Hong Kong University of Science and Technology, Hong Kong 999077, PR China
| | - Ding Pan
- Department of Physics and Department of Chemistry, The Hong Kong University of Science and Technology, Hong Kong 999077, PR China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong 999077, PR China
| | - Junzhi Liu
- State Key Laboratory of Synthetic Chemistry, HKU-CAS Joint Laboratory on New Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong 999077, PR China
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2
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Lupi M, Fabbri M, Mazzeo G, Longhi G, Abbate S, Viglianisi C, Menichetti S. Organocatalytic hydrogen bond donor/Lewis base (HBD/LB) synthesis and chiroptical properties of thiabridged [5]helicenes. Org Biomol Chem 2024. [PMID: 39040026 DOI: 10.1039/d4ob00979g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Thiabridged [5]helicenes are obtained from thioaryl-N-phthalimido benzo[a]phenothiazines using a hydrogen bond donor/Lewis base organocatalytic approach. Resolution of [5]helicenes using either (1S)-(-)-camphanic acid as a chiral auxiliary or CSP-HPLC is reported. Thiabridged [5]helicenes show an exceptional configurational stability with racemization energy barriers higher than 40 kcal mol-1. Electronic circular dichroism and TD-DFT calculations permit the assignment of the absolute configuration, demonstrating that the sign of optical rotation is not easily related to the M or P structure. Separated enantiomers show circularly polarized luminescence with high dissymmetry ratio.
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Affiliation(s)
- Michela Lupi
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Via della Lastruccia 13, Sesto Fiorentino (FI), 50019 Florence, Italy.
| | - Mosè Fabbri
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Via della Lastruccia 13, Sesto Fiorentino (FI), 50019 Florence, Italy.
| | - Giuseppe Mazzeo
- Department of Molecular and Translational Medicine (DMMT), University of Brescia, V. le Europa 11, Brescia (BS), 25121 Brescia, Italy
| | - Giovanna Longhi
- Department of Molecular and Translational Medicine (DMMT), University of Brescia, V. le Europa 11, Brescia (BS), 25121 Brescia, Italy
| | - Sergio Abbate
- Department of Molecular and Translational Medicine (DMMT), University of Brescia, V. le Europa 11, Brescia (BS), 25121 Brescia, Italy
| | - Caterina Viglianisi
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Via della Lastruccia 13, Sesto Fiorentino (FI), 50019 Florence, Italy.
| | - Stefano Menichetti
- Department of Chemistry "Ugo Schiff" (DICUS), University of Florence, Via della Lastruccia 13, Sesto Fiorentino (FI), 50019 Florence, Italy.
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3
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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; 30: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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4
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Matsuo Y, Gon M, Tanaka K, Seki S, Tanaka T. Synthesis of Aza[ n]helicenes up to n = 19: Hydrogen-Bond-Assisted Solubility and Benzannulation Strategy. J Am Chem Soc 2024; 146:17428-17437. [PMID: 38866732 DOI: 10.1021/jacs.4c05156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Synthetic challenges toward anomalous structures and electronic states often involve handling problems such as insolubility in common organic solvents and oxidative degradation under aerobic conditions. We designed benzo-annulated aza[n]helicenes, which benefit from both the suppressed elevation of highest occupied molecular orbital (HOMO) energies and high solubility due to hydrogen bonding with solvent molecules to overcome these challenges. This strategy enabled the synthesis of six new aza[n]helicenes ([n]AHs) of different lengths (n = 9-19) from acyclic precursors via one-pot intramolecular oxidative fusion reactions. The structures of all of the synthesized aza[n]helicenes were determined by X-ray diffraction (XRD) analysis, and their electrochemical potentials were measured by cyclic voltammetry. Among the synthesized aza[n]helicenes, [17]AH and [19]AH are the first heterohelicenes with a triple-layered helix. The noncovalent interaction (NCI) plots confirm the existence of an effective π-π interaction between the layers. The absorption and fluorescence spectra red-shifted as the helical lengths increased, without any distinct saturation points. The optical resolutions of N-butylated [9]AH, [11]AH, [13]AH, and [15]AH were accomplished, and their circular dichroism (CD) and circularly polarized luminescence (CPL) were measured. Thus, the structural, (chir)optical, and electrochemical properties of the aza[n]helicenes were comprehensively analyzed.
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Affiliation(s)
- Yusuke Matsuo
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Masayuki Gon
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kazuo Tanaka
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Shu Seki
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Takayuki Tanaka
- Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
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5
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Hirano J, Miyoshi S, Yashima E, Ikai T, Shinokubo H, Fukui N. Synthesis of sterically congested double helicene by alkyne cycloisomerization. Chem Commun (Camb) 2024; 60:6035-6038. [PMID: 38775051 DOI: 10.1039/d4cc01573h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
Alkyne cycloisomerization of 2,7,10,15-tetra(ortho-alkynylphenyl)benzo[g,p]chrysene containing bulky 4-alkoxy-2,6-dimethylphenyl groups at the alkyne terminals selectively proceeded at the sterically crowded bay-region. The obtained double helicene adopts a distorted structure with a high racemization barrier due to the intramolecular steric repulsion.
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Affiliation(s)
- Junichiro Hirano
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan.
| | - Sayaka Miyoshi
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan.
| | - Eiji Yashima
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan.
| | - Tomoyuki Ikai
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan.
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Hiroshi Shinokubo
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan.
- Integrated Research Consortium on Chemical Science (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Norihito Fukui
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan.
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
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6
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Watanabe K, Tsurumaki E, Hasegawa M, Toyota S. Structure and Chiroptical Properties of Anthra[1,2-a]anthracene-1-yl Dimers as New Biaryls. Chemistry 2024; 30:e202400929. [PMID: 38554080 DOI: 10.1002/chem.202400929] [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: 03/05/2024] [Revised: 03/23/2024] [Accepted: 03/30/2024] [Indexed: 04/01/2024]
Abstract
Dimers of anthra[1,2-a]anthracene-1-yl units and its mesityl derivative were synthesized by Ni(0)-mediated coupling of the corresponding chloro derivatives as new biaryls. The X-ray analysis and DFT calculations revealed that two polycyclic aromatic units with nonplanar deformations took a twisted conformation about the single bond as a chiral axis. Enantiomers of the nonsubstituted compound were resolved by chiral HPLC, and the enantiopure samples showed intense Cotton effects at 321 nm in the circular dichroism (CD) spectra and emission bands at 449 nm in the circularly polarized luminescence (CPL) spectra with dissymmetry factor of |glum| 3.6×10-3. The absolute stereochemistry of this biaryl was determined by the theoretical calculation of CD spectrum by the time-dependent DFT method. The barrier to enantiomerization was determined to be 108 kJ mol-1 at 298 K. The dynamic process proceeded via a stepwise mechanism involving the helical inversion of each aromatic unit and the rotation about the biaryl axis as analyzed by the DFT calculations.
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Affiliation(s)
- Kota Watanabe
- 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
| | - Masashi Hasegawa
- Department of Chemistry, School of Science, Kitasato University, Sagamihara, Kanagawa, 252-0373, 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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7
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Niu W, Fu Y, Deng Q, Qiu ZL, Liu F, Popov AA, Komber H, Ma J, Feng X. Enhancing Chiroptical Responses in Helical Nanographenes via Geometric Engineering of Double [7]Helicenes. Angew Chem Int Ed Engl 2024; 63:e202319874. [PMID: 38372180 DOI: 10.1002/anie.202319874] [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: 12/22/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/20/2024]
Abstract
Helical nanographenes with high quantum yields and strong chiroptical responses are pivotal for developing circularly polarized luminescence (CPL) materials. Here, we present the successful synthesis of novel π-extended double [7]helicenes (ED7Hs) where two helicene units are fused at the meta- or para-position of the middle benzene ring, respectively, as the structural isomers of the reported ortho-fused ED7H. The structural geometry of these ED7Hs is clearly characterized by single-crystal X-ray analysis. Notably, this class of ED7Hs exhibits bright luminescence with high quantum yields exceeding 40 %. Through geometric regulation of two embedded [7]helicene units from ortho-, meta- to para-position, these ED7Hs display exceptional amplification in chiroptical responses. This enhancement is evident in a remarkable approximate fivefold increase in the absorbance and luminescence dissymmetry factors (gabs and glum), respectively, along with a boosted CPL brightness up to 176 M-1 cm-1, surpassing the performance of most helicene-based chiral NGs. Furthermore, DFT calculations elucidate that the geometric adjustment of two [7]helicene units allows the precise alignment of electric and magnetic transition dipole moments, leading to the observed enhancement of their chiroptical responses. This study offers an effective strategy for magnifying the CPL performance in chiral NGs, promoting their expanded application as CPL emitters.
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Affiliation(s)
- Wenhui Niu
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle, 06120, Germany
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
| | - Yubin Fu
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle, 06120, Germany
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
| | - Qingsong Deng
- State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Zhen-Lin Qiu
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
| | - Fupin Liu
- Leibniz Institute for Solid State and Materials Research, 01069, Dresden, Germany
| | - Alexey A Popov
- Leibniz Institute for Solid State and Materials Research, 01069, Dresden, Germany
| | - Hartmut Komber
- Leibniz-Institut für Polymerforschung Dresden e. V., Hohe Straße 6, 01069, Dresden, Germany
| | - Ji Ma
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle, 06120, Germany
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
- College of Materials Science and Opto-Electronic Technology & Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Science, 100049, Beijing, P. R. China
| | - Xinliang Feng
- Max Planck Institute of Microstructure Physics, Weinberg 2, Halle, 06120, Germany
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
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8
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Huo GF, Xu WT, Han Y, Zhu J, Hou X, Fan W, Ni Y, Wu S, Yang HB, Wu J. Expanded Azahelicenes with Large Dissymmetry Factors. Angew Chem Int Ed Engl 2024; 63:e202403149. [PMID: 38421194 DOI: 10.1002/anie.202403149] [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: 02/14/2024] [Revised: 02/29/2024] [Accepted: 02/29/2024] [Indexed: 03/02/2024]
Abstract
Expanded azahelicenes, as heteroanalogues of helically chiral helicenes, hold significant potential for chiroptical materials. Nevertheless, their investigation and research have remained largely unexplored. Herein, we present the facile synthesis of a series of expanded azahelicenes NHn (n=1-5) consisting of 11, 19, 27, 35, and 43 fused rings, mainly by Suzuki coupling followed by Bi(OTf)3-mediated cyclization of vinyl ethers. The structures of NH2, NH3 and NH4 were confirmed through X-ray crystallography analysis, and their (P)- and (M)- enantiomers were also isolated with chiral high performance liquid chromatography. The enantiomers exhibit large absorption (abs) and luminescence (lum) dissymmetry factors, with |gabs|max=0.044; |glum|max=0.003 for NH2, |gabs|max=0.048; |glum|=0.014 for NH3, and |gabs|max=0.043; |glum|max=0.021 for NH4, which are superior to their respective all-carbon analogues.
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Affiliation(s)
- Gui-Fei Huo
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Wei-Tao Xu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - Yi Han
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Jun Zhu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Xudong Hou
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Wei Fan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Yong Ni
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Shaofei Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
| | - Hai-Bo Yang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore
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9
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Pinar Solé A, Klívar J, Šámal M, Stará IG, Starý I, Mendieta-Moreno JI, Ernst KH, Jelínek P, Stetsovych O. On-Surface Synthesis of Helicene Oligomers. Chemistry 2024:e202304127. [PMID: 38587984 DOI: 10.1002/chem.202304127] [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: 12/14/2023] [Revised: 04/03/2024] [Accepted: 04/07/2024] [Indexed: 04/10/2024]
Abstract
We report on-surface synthesis of heterochiral 1D heptahelicene oligomers after deposition of a racemic heptahelicene monomer on an Au(111) surface followed by Ullmann coupling under ultrahigh vacuum conditions. Structure, chirality and mode of adsorption of the resulting dimers to octamers are inferred from the scanning probe microscopy and theoretical calculations.
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Affiliation(s)
- Andrés Pinar Solé
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague, Czech Republic
| | - Jiří Klívar
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague 6, Czech Republic
| | - Michal Šámal
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague 6, Czech Republic
| | - Irena G Stará
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague 6, Czech Republic
| | - Ivo Starý
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, 166 10, Prague 6, Czech Republic
| | - Jesús I Mendieta-Moreno
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague, Czech Republic
- Universidad Autónoma de Madrid, Theoretical Condensed Matter Physics Department, C/ Francisco Tomás y, Valiente 7, Module 05, Facultad de Ciencias, E-28049, Madrid, Spain
| | - Karl-Heinz Ernst
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague, Czech Republic
- Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600, Dübendorf, Switzerland
- University of Zurich Department of Chemistry, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Pavel Jelínek
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague, Czech Republic
| | - Oleksandr Stetsovych
- Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague, Czech Republic
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10
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Guo H, Lovell JB, Shu C, Pink M, Morton M, Rajca S, Rajca A. Chiral π-Conjugated Double Helical Aminyl Diradical with the Triplet Ground State. J Am Chem Soc 2024; 146:9422-9433. [PMID: 38501228 DOI: 10.1021/jacs.4c02057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
We report a neutral high-spin diradical of chiral C2-symmetric bis[5]diazahelicene with ΔEST ≈ 0.4 kcal mol-1, as determined by EPR spectroscopy/SQUID magnetometry. The diradical is the most persistent among all high-spin aminyl radicals reported to date by a factor of 20, with a half-life of up to 6 days in 2-MeTHF at room temperature. Its triplet ground state and excellent persistence may be associated with the unique spin density distribution within the dihydrophenazine moiety, which characterizes two effective 3-electron C-N bonds analogous to the N-O bond of a nitroxide radical. The enantiomerically enriched (ee ≥ 94%) (MM)- and (PP)-enantiomers of the precursors to the diradicals are obtained by either preparative chiral supercritical fluid chromatography or resolution via functionalization with the chiral auxiliary of the C2-symmetric racemic tetraamine. The barrier for the racemization of the solid tetraamine is ΔG‡ = 43 ± 0.01 kcal mol-1 in the 483-523 K range. The experimentally estimated lower limit of the barrier for the racemization of a diradical, ΔG‡ ≥ 26 kcal mol-1 in 2-MeTHF at 293 K, is comparable to the DFT-determined barrier of ΔG‡ = 31 kcal mol-1 in the gas phase at 298 K. While the enantiomerically pure tetraamine displays strong chiroptical properties, with anisotropy factor |g| = |Δε|/ε = 0.036 at 376 nm, |g| ≈ 0.005 at 548 nm of the high-spin diradical is comparable to that recently reported triplet ground-state diradical dication. Notably, the radical anion intermediate in the generation of diradical exhibits a large SOMO-HOMO inversion, SHI = 35 kcal mol-1.
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Affiliation(s)
- Haoxin Guo
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Joshua B Lovell
- Teledyne ISCO, 4700 Superior Street, Lincoln, Nebraska 68504-1328, United States
| | - Chan Shu
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Maren Pink
- IUMSC, Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102, United States
| | - Martha Morton
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Suchada Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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11
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Yuan WC, Zeng HY, Zhang YP, Zhao JQ, You Y, Yin JQ, Zhou MQ, Wang ZH. Synthesis of Benzofuro[3,2- b]indol-3-one Derivatives via Dearomative (3 + 2) Cycloaddition of 2-Nitrobenzofurans and para-Quinamines. Molecules 2024; 29:1163. [PMID: 38474676 DOI: 10.3390/molecules29051163] [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: 02/08/2024] [Revised: 03/02/2024] [Accepted: 03/02/2024] [Indexed: 03/14/2024] Open
Abstract
An efficient dearomative (3 + 2) cycloaddition of para-quinamines and 2-nitrobenzofurans has been developed. This reaction proceeds smoothly under mild conditions and affords a series of benzofuro[3,2-b]indol-3-one derivatives in good to excellent yields (up to 98%) with perfect diastereoselectivities (all cases > 20:1 dr). The scale-up synthesis and versatile derivatizations demonstrate the potential synthetic application of the protocol. A plausible reaction mechanism is also proposed to account for the observed reaction process. This work represents the first instance of the N-triggered dearomative (3 + 2) cycloaddition of 2-nitrobenzofurans.
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Affiliation(s)
- Wei-Cheng Yuan
- Innovation Research Center of Chiral Drugs, Institute for Advanced Study, Chengdu University, Chengdu 610106, China
- China National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China
| | - Hai-Ying Zeng
- Innovation Research Center of Chiral Drugs, Institute for Advanced Study, Chengdu University, Chengdu 610106, China
- China National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China
| | - Yan-Ping Zhang
- Innovation Research Center of Chiral Drugs, Institute for Advanced Study, Chengdu University, Chengdu 610106, China
| | - Jian-Qiang Zhao
- Innovation Research Center of Chiral Drugs, Institute for Advanced Study, Chengdu University, Chengdu 610106, China
| | - Yong You
- Innovation Research Center of Chiral Drugs, Institute for Advanced Study, Chengdu University, Chengdu 610106, China
| | - Jun-Qing Yin
- Innovation Research Center of Chiral Drugs, Institute for Advanced Study, Chengdu University, Chengdu 610106, China
| | - Ming-Qiang Zhou
- China National Engineering Research Center of Chiral Drugs, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China
| | - Zhen-Hua Wang
- Innovation Research Center of Chiral Drugs, Institute for Advanced Study, Chengdu University, Chengdu 610106, China
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12
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Uceda RG, Cruz CM, Míguez-Lago S, de Cienfuegos LÁ, Longhi G, Pelta DA, Novoa P, Mota AJ, Cuerva JM, Miguel D. Can Magnetic Dipole Transition Moment Be Engineered? Angew Chem Int Ed Engl 2024; 63:e202316696. [PMID: 38051776 DOI: 10.1002/anie.202316696] [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: 11/03/2023] [Revised: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
The development of chiral compounds with enhanced chiroptical properties is an important challenge to improve device applications. To that end, an optimization of the electric and magnetic dipole transition moments of the molecule is necessary. Nevertheless, the relationship between chemical structure and such quantum mechanical properties is not always clear. That is the case of magnetic dipole transition moment (m) for which no general trends for its optimization have been suggested. In this work we propose a general rationalization for improving the magnitude of m in different families of chiral compounds. Performing a clustering analysis of hundreds of transitions, we have been able to identify a single group in which |m| value is maximized along the helix axis. More interestingly, we have found an accurate linear relationship (up to R2 =0.994) between the maximum value of this parameter and the area of the inner cavity of the helix, thus resembling classical behavior of solenoids. This research provides a tool for the rationalized synthesis of compounds with improved chiroptical responses.
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Affiliation(s)
- Rafael G Uceda
- Departamento de Química Orgánica, Unidad de Excelencia de Química Aplicada a la Biomedicina y Medioambiente (UEQ), Universidad de Granada (UGR), Facultad de Ciencias C. U. Fuentenueva, 18071, Granada, Spain
| | - Carlos M Cruz
- Departamento de Química Orgánica, Unidad de Excelencia de Química Aplicada a la Biomedicina y Medioambiente (UEQ), Universidad de Granada (UGR), Facultad de Ciencias C. U. Fuentenueva, 18071, Granada, Spain
| | - Sandra Míguez-Lago
- Departamento de Química Orgánica, Unidad de Excelencia de Química Aplicada a la Biomedicina y Medioambiente (UEQ), Universidad de Granada (UGR), Facultad de Ciencias C. U. Fuentenueva, 18071, Granada, Spain
| | - Luis Álvarez de Cienfuegos
- Departamento de Química Orgánica, Unidad de Excelencia de Química Aplicada a la Biomedicina y Medioambiente (UEQ), Universidad de Granada (UGR), Facultad de Ciencias C. U. Fuentenueva, 18071, Granada, Spain
| | - Giovanna Longhi
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia, Viale Europa 11, 25123, Brescia, Italy
| | - David A Pelta
- Departamento de Ciencias de la Computación e Inteligencia Artificial, UGR C/Periodista Daniel Saucedo Aranda S/N, 18071, Granada, Spain
| | - Pavel Novoa
- Departamento de Ciencias de la Computación e Inteligencia Artificial, UGR C/Periodista Daniel Saucedo Aranda S/N, 18071, Granada, Spain
| | - Antonio J Mota
- Departamento de Química Inorgánica, UEQ, UGR, Facultad de Ciencias C. U. Fuentenueva, 18071, Granada, Spain
| | - Juan M Cuerva
- Departamento de Química Orgánica, Unidad de Excelencia de Química Aplicada a la Biomedicina y Medioambiente (UEQ), Universidad de Granada (UGR), Facultad de Ciencias C. U. Fuentenueva, 18071, Granada, Spain
| | - Delia Miguel
- Departamento de Fisicoquímica, UEQ, UGR, Facultad de Farmacia Avda. Profesor Clavera S/N, 18071, Granada, Spain
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13
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Li R, Ma B, Li S, Lu C, An P. Chalcogen-doped, ( seco)-hexabenzocoronene-based nanographenes: synthesis, properties, and chalcogen extrusion conversion. Chem Sci 2023; 14:8905-8913. [PMID: 37621425 PMCID: PMC10445433 DOI: 10.1039/d3sc02595k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 07/16/2023] [Indexed: 08/26/2023] Open
Abstract
A series of chalcogen-doped nanographenes (NGs) and their oxides are described. Their molecular design is conceptually based on the insertion of different chalcogens into the hexa-peri-hexabenzocoronene (HBC) backbone. All the NGs adopt nonplanar conformations, which would show better solubility compared to planar HBC. Except for the oxygen-doped, saddle-shaped NG, the insertion of large chalcogens like sulfur and selenium leads to a seco-HBC-based, helical geometry. All the three-dimensional structures are unambiguously confirmed by single-crystal X-ray diffractometry. Their photophysical properties including UV-vis absorption, fluorescence, chiroptical, charge distribution, and orbital gaps are investigated experimentally or theoretically. The properties of each structure are significantly affected by the doped chalcogen and its related oxidative state. Notably, upon heating or adding an acid, the selenium-doped NG or its oxide undergoes a selenium extrusion reaction to afford seco-HBC or HBC quantitatively, which can be treated as precursors of hydrocarbon HBCs.
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Affiliation(s)
- Ranran Li
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
| | - Bin Ma
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
| | - Shengtao Li
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
| | - Chongdao Lu
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
| | - Peng An
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
- Key Laboratory of Medicinal Chemistry for Natural Resource, Ministry of Education, Yunnan University Kunming 650091 P. R. China
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14
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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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15
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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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