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Borstelmann J, Schneider L, Rominger F, Deschler F, Kivala M. Helically Chiral π-Expanded Azocines Through Regioselective Beckmann Rearrangement and Their Charged States. Angew Chem Int Ed Engl 2024:e202405570. [PMID: 38716767 DOI: 10.1002/anie.202405570] [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: 03/21/2024] [Indexed: 06/16/2024]
Abstract
We report a synthetic approach to π-expanded [6]helicenes incorporating tropone and azocine units in combination with a 5-membered ring, which exhibit intriguing structural, electronic, and chiroptical properties. The regioselective Beckmann rearrangement allows the isolation of helical scaffolds containing 8-membered lactam, azocine, and amine units. As shown by X-ray crystallographic analysis, the incorporation of tropone or azocine units leads to highly distorted [6]helicene moieties, with distinct packing motifs in the solid state. The compounds exhibit promising optoelectronic properties with considerable photoluminescence quantum yields and tunable emission wavelengths depending on the relative position of the nitrogen center within the polycyclic framework. Separation of the enantiomers by chiral high-performance liquid chromatography (HPLC) allowed characterization of their chiroptical properties by circular dichroism (CD) and circularly polarized luminescence (CPL) spectroscopy. The azocine compounds feature manifold redox chemistry, allowing for the characterization of the corresponding radical anions and cations as well as the dications and dianions, with near-infrared (NIR) absorption bands extending beyond 3000 nm. Detailed theoretical studies provided insights into the aromaticity evolution upon reduction and oxidation, suggesting that the steric strain prevents the azocine unit from undergoing aromatization, while the indene moiety dominates the observed redox chemistry.
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Affiliation(s)
- Jan Borstelmann
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Lars Schneider
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Felix Deschler
- Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120, Heidelberg, Germany
| | - Milan Kivala
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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Liu J, Hong J, Liao Z, Tan J, Liu H, Dmitrieva E, Zhou L, Ren J, Cao XY, Popov AA, Zou Y, Narita A, Hu Y. Negatively Curved Octagon-Incorporated Aza-nanographene and its Assembly with Fullerenes. Angew Chem Int Ed Engl 2024; 63:e202400172. [PMID: 38345140 DOI: 10.1002/anie.202400172] [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: 01/03/2024] [Indexed: 03/01/2024]
Abstract
A negatively curved aza-nanographene (NG) containing two octagons was synthesized by a regioselective and stepwise cyclodehydrogenation procedure, in which a double aza[7]helicene was simultaneously formed as an intermediate. Their saddle-shaped structures with negative curvature were unambiguously confirmed by X-ray crystallography, thereby enabling the exploration of the structure-property relationship by photophysical, electrochemical and conformational studies. Moreover, the assembly of the octagon-embedded aza-NG with fullerenes was probed by fluorescence spectral titration, with record-high binding constants (Ka=9.5×103 M-1 with C60, Ka=3.7×104 M-1 with C70) found among reported negatively curved polycyclic aromatic compounds. The tight association of aza-NG with C60 was further elucidated by X-ray diffraction analysis of their co-crystal, which showed the formation of a 1 : 1 complex with substantial concave-convex interactions.
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Affiliation(s)
- Jun Liu
- College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
| | - Juan Hong
- College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
| | - Zhenxing Liao
- College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
| | - Jingyun Tan
- Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Haoliang Liu
- Department of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China
| | - Evgenia Dmitrieva
- Center of Spectroelectrochemistry, Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Long Zhou
- College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
| | - Jie Ren
- MOE Key Laboratory of Macromolecular Synthesis and Functionalization, International Research Center for X Polymers Department of Polymer Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Xiao-Yu Cao
- Department of Chemistry and Chemical Engineering, Xiamen University, 361005, Xiamen, China
| | - Alexey A Popov
- Center of Spectroelectrochemistry, Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069, Dresden, Germany
| | - Yingping Zou
- College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
| | - Akimitsu Narita
- Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Yunbin Hu
- College of Chemistry and Chemical Engineering, Central South University, 410083, Changsha, China
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Venugopal G, Kumar V, Badrinarayan Jadhav A, Dongre SD, Khan A, Gonnade R, Kumar J, Santhosh Babu S. Boron- and Oxygen-Doped π-Extended Helical Nanographene with Circularly Polarised Thermally Activated Delayed Fluorescence. Chemistry 2024; 30:e202304169. [PMID: 38270385 DOI: 10.1002/chem.202304169] [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: 12/29/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 01/26/2024]
Abstract
Helical nanographenes have garnered substantial attention owing to their finely adjustable optical and semiconducting properties. The strategic integration of both helicity and heteroatoms into the nanographene structure, facilitated by a boron-oxygen-based multiple resonance (MR) thermally activated delayed fluorescence (TADF), elevates its photophysical and chiroptical features. This signifies the introduction of an elegant category of helical nanographene that combines optical (TADF) and chiroptical (CPL) features. In this direction, we report the synthesis, optical, and chiroptical properties of boron, oxygen-doped Π-extended helical nanographene. The π-extension induces distortion in the DOBNA-incorporated nanographene, endowing a pair of helicenes, (P)-B2NG, and (M)-B2NG exhibiting circularly polarized luminescence with glum of -2.3×10-3 and +2.5×10-3, respectively. B2NG exhibited MR-TADF with a lifetime below 5 μs, and a reasonably high fluorescence quantum yield (50 %). Our molecular design enriches the optical and chiroptical properties of nanographenes and opens up new opportunities in multidisciplinary fields.
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Affiliation(s)
- Geethu Venugopal
- CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411 008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India
| | - Viksit Kumar
- CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411 008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India
| | - Ashok Badrinarayan Jadhav
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati, 517507, India
| | - Sangram D Dongre
- CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411 008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India
| | - Abujunaid Khan
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India
- NCIM-Resource Center, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Rajesh Gonnade
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411 008, India
| | - Jatish Kumar
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Tirupati, 517507, India
| | - Sukumaran Santhosh Babu
- CSIR-National Chemical Laboratory (CSIR-NCL), Dr. Homi Bhabha Road, Pune, 411 008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India
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Ruan L, Luo W, Zhang H, Liu P, Shi Y, An P. Cycl[2,2,4]azine-embedded non-alternant nanographenes containing fused antiaromatic azepine ring. Chem Sci 2024; 15:1511-1519. [PMID: 38274082 PMCID: PMC10806646 DOI: 10.1039/d3sc05515a] [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: 10/17/2023] [Accepted: 12/14/2023] [Indexed: 01/27/2024] Open
Abstract
The development of non-alternant nanographenes has attracted considerable attention due to their unique photophysical properties. Herein, we reported a novel aza-doped, non-alternant nanographene (NG) 1 by embedding the cycl[2,2,4]azine unit into the benzenoid NG framework. Single-crystal X-ray diffractometry suggests saddle or twisted nonplanar geometry of the entire backbone of 1 and coplanar conformation of the cycl[2,2,4]azine unit. DFT calculation together with solid structure indicates that NG 1 possesses significant local antiaromaticity in the azepine ring. By oxidative process or trifluoroacetic acid treatment, this nanographene can transform into a mono-radical cation, which was confirmed by UV/Vis absorption, 1H NMR, and electron paramagnetic resonance (EPR) spectroscopy. The antiaromaticity/aromaticity switching of the azepine ring on 1˙+ from 1 enables the high stability of this radical cation, which remained intact for over 1 day. Due to the electron-donating nature of the nitrogen and the unique electronic structure, NG 1 exhibits strong electron-donating properties, as proved by the intermolecular charge transfer towards C60 with a high association constant. Furthermore, selective modification of NG 1 was accomplished by Vilsmeier reaction, and the derivatives 7 and 8 with substituted benzophenone were obtained. The photophysical and electronic properties can be tuned by the introduction of different electronic groups in benzophenone.
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Affiliation(s)
- Lan Ruan
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
| | - Wanhua Luo
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
| | - Haifan Zhang
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
| | - Peng Liu
- School of Chemical Science and Technology, Yunnan University Kunming 650091 P. R. China
| | - Yong Shi
- 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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Ji B, Qi Z, Ye T, Li S, Shi Y, Cui S, Xiao J. Straightforward Synthesis of Pentagon-Embedded Expanded [11]Helicenes for Radiative Cooling Property. Chemistry 2024; 30:e202302893. [PMID: 37867144 DOI: 10.1002/chem.202302893] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 10/24/2023]
Abstract
Two new pentagon-embedded carbo[11]helicenes have been designed and synthesized in a three-step process, which are the first example of carbo[11]helicenes through the post-functionalization of twistacene. TD-DFT analyses indicate that both of them possess high enantiomerization barriers of 42.29 kcal/mol and 40.76 kcal/mol, respectively. They emit strong red fluorescence and can be chemically oxidized into stable cationic radicals upon addition of AgSbF6 evidenced by the bathochromic-shifted absorption spectra and the appearance of electronic paramagnetic resonance (EPR) signals. In addition, such helical derivatives can be chosen as radiative cooling materials in a glass model house, and the maxima of 5.4 °C for the former and 6.5 °C for the latter are found in the comparative tests, which might be caused by the NIR reflective response.
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Affiliation(s)
- Bingliang Ji
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding, 071002, P. R. China
| | - Zewei Qi
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding, 071002, P. R. China
| | - Tongtong Ye
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding, 071002, P. R. China
| | - Shuangxuan Li
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding, 071002, P. R. China
| | - Yanwei Shi
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding, 071002, P. R. China
| | - Shuang Cui
- Division of Analysis, SINOPEC (Beijing) Research Institute of Chemical Industry, Co. Ltd., Beijing, P. R. China
| | - Jinchong Xiao
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding, 071002, P. R. China
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Qi Z, Shang H, Ji B, Shi Y, Ye T, Li Y, Xiao J. Heptagon-Embedded Helicene Derivatives: Synthesis, Crystal Structural Analyses, and Circularly Polarized Luminescence. J Org Chem 2023; 88:14550-14558. [PMID: 37812747 DOI: 10.1021/acs.joc.3c01563] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Two pairs of isomers of heptagon-embedded helical arenes (3/6 and 10/13) have been strategically prepared, where the molecular structures of 3 and 13 have been identified through single crystal X-ray diffraction analysis. The effect of the heptagon unit on the physical properties of 3, 6, 10, and 13 is investigated in a comparative manner, and the results indicate that the optical enantiomers of 13 obtained from HPLC exhibit promising chiroptical properties.
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Affiliation(s)
- Zewei Qi
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding 071002, P. R. China
| | - Honglin Shang
- Department of Physics, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Bingliang Ji
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding 071002, P. R. China
| | - Yanwei Shi
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding 071002, P. R. China
| | - Tongtong Ye
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding 071002, P. R. China
| | - Yiming Li
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Hebei University, Baoding 071002, P. R. China
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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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Li R, Wang D, Li S, An P. Construction of hexabenzocoronene-based chiral nanographenes. Beilstein J Org Chem 2023; 19:736-751. [PMID: 37284588 PMCID: PMC10241098 DOI: 10.3762/bjoc.19.54] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/17/2023] [Indexed: 06/08/2023] Open
Abstract
The past decade witnessed remarkable success in synthetic molecular nanographenes. Encouraged by the widespread application of chiral nanomaterials, the design, and construction of chiral nanographenes is a hot topic recently. As a classic nanographene unit, hexa-peri-hexabenzocoronene generally serves as the building block for nanographene synthesis. This review summarizes the representative examples of hexa-peri-hexabenzocoronene-based chiral nanographenes.
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Affiliation(s)
- Ranran Li
- School of Chemical Science and Technology, Yunnan University, Kunming 650500, P. R. China
| | - Di Wang
- School of Chemical Science and Technology, Yunnan University, Kunming 650500, P. R. China
| | - Shengtao Li
- School of Chemical Science and Technology, Yunnan University, Kunming 650500, P. R. China
| | - Peng An
- School of Chemical Science and Technology, Yunnan University, Kunming 650500, P. R. China
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