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Stockerl WJ, Reißenweber L, Gerwien A, Bach NN, Thumser S, Mayer P, Gschwind RM, Dube H. Azotriptycenes: Photoswitchable Molecular Brakes. Chemistry 2024; 30:e202302267. [PMID: 37779321 DOI: 10.1002/chem.202302267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 09/24/2023] [Accepted: 09/27/2023] [Indexed: 10/03/2023]
Abstract
The control of molecular motions is a central topic of molecular machine research. Molecular brakes are fundamental building blocks towards such goal as they allow deliberately decelerating specific motions after an outside stimulus is applied. Here we present azotriptycenes as structural framework for light-controlled molecular brakes. The intrinsic kinetics and their changes upon azotriptycene isomerization are scrutinized comprehensively by a mixed theoretical and variable temperature NMR approach. With azotriptycenes C-N bond rotation rates can be decelerated or accelerated reversibly by up to five orders of magnitude. Rate change effects are highly localized and are strongest for the C-N bond connecting a triptycene rotor fragment to the central diazo group. The detailed mechanistic insights provide a solid basis for further conscious design and applications in the future.
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Affiliation(s)
- Willibald J Stockerl
- Institut für Organische Chemie, Universität Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Lilli Reißenweber
- Department of Chemistry and Pharmacy, Friedrich-Alexander Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Aaron Gerwien
- Department of Chemistry and Center for Integrated Protein Science CIPSM, Ludwig-Maximilians Universität München, Butenandtstr. 5-13, 81377, Munich, Germany
| | - Nicolai N Bach
- Department of Chemistry and Pharmacy, Friedrich-Alexander Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Stefan Thumser
- Department of Chemistry and Pharmacy, Friedrich-Alexander Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Peter Mayer
- Department of Chemistry and Center for Integrated Protein Science CIPSM, Ludwig-Maximilians Universität München, Butenandtstr. 5-13, 81377, Munich, Germany
| | - Ruth M Gschwind
- Institut für Organische Chemie, Universität Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
| | - Henry Dube
- Department of Chemistry and Pharmacy, Friedrich-Alexander Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
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2
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Lin B, Karki I, Pellechia PJ, Shimizu KD. Electrostatically-gated molecular rotors. Chem Commun (Camb) 2022; 58:5869-5872. [DOI: 10.1039/d2cc00512c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ability to control molecular-scale motion using electrostatic interactions was demonstrated using an N-phenylsuccinimide molecular rotor with an electrostatic pyridyl-gate. Protonation of the pyridal-gate forms stabilizing electrostatic interactions in the...
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3
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Komiya N, Ikeshita M, Tosaki K, Sato A, Itami N, Naota T. Catalytic Enantioselective Rotation of Watermill‐Shaped Dinuclear Pd Complexes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100140] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Naruyoshi Komiya
- Department of Chemistry, Graduate School of Engineering Science Osaka University Machikaneyama, Toyonaka, Osaka 560-8531 Japan
- Chemistry Laboratory The Jikei University School of Medicine Kokuryo, Chofu, Tokyo 182-8570 Japan
| | - Masahiro Ikeshita
- Department of Chemistry, Graduate School of Engineering Science Osaka University Machikaneyama, Toyonaka, Osaka 560-8531 Japan
| | - Koichi Tosaki
- Department of Chemistry, Graduate School of Engineering Science Osaka University Machikaneyama, Toyonaka, Osaka 560-8531 Japan
| | - Atsushi Sato
- Department of Chemistry, Graduate School of Engineering Science Osaka University Machikaneyama, Toyonaka, Osaka 560-8531 Japan
| | - Nao Itami
- Department of Chemistry, Graduate School of Engineering Science Osaka University Machikaneyama, Toyonaka, Osaka 560-8531 Japan
| | - Takeshi Naota
- Department of Chemistry, Graduate School of Engineering Science Osaka University Machikaneyama, Toyonaka, Osaka 560-8531 Japan
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Lien CY, Hsu YF, Liu YH, Peng SM, Shinmyozu T, Yang JS. Steric Engineering of Cyclometalated Pt(II) Complexes toward High-Contrast Monomer-Excimer-Based Mechanochromic and Vapochromic Luminescence. Inorg Chem 2020; 59:11584-11594. [PMID: 32799471 DOI: 10.1021/acs.inorgchem.0c01390] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Ligands play a crucial role in the supramolecular photoluminescence properties of Pt(II) square-planar complexes. To improve the luminescence color responses of N∧C∧N cyclometalated Pt(II) complexes to external stimuli such as mechanical stress and chemical vapors, we have conducted a steric engineering of the previous systems 1a-1d [Inorg. Chem. 2017, 56, 4978-4989] by introducing two tert-butyl groups to the tridentate ligand to form complexes 2a-2c. Unlike the "too low" or "too high" steric hindrance of the NCNPt core in 1a-1d, the combined steric effects of the tert-butyl groups at one side and the pentiptycene group at the other side of the NCNPt core in 2b are "just right" for generating as-prepared powders with pure monomer (green) emission or pure excimer (red) emission, depending on the rate of precipitation from solutions. The synergistic steric effects are also beneficial to the solid-state luminescence quantum efficiency (30-36%). As a result of the differences in steric interactions and thus in the relative monomer vs excimer emission intensity, each complex of 2a-2c performs a two-step luminescence mechanochromism and vapochromism with different color patterns. This work provides an intriguing example of steric engineering of Pt(II) complexes toward highly emissive molecular solids with high-contrast mechanochromic and vapochromic luminescence.
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Affiliation(s)
- Chen-Yu Lien
- Department of Chemistry, National Taiwan University No 1 Sec 4 Roosevelt Road, Taipei 10617, Taiwan (R.O.C.)
| | - Ying-Feng Hsu
- Department of Chemistry, National Taiwan University No 1 Sec 4 Roosevelt Road, Taipei 10617, Taiwan (R.O.C.)
| | - Yi-Hung Liu
- Department of Chemistry, National Taiwan University No 1 Sec 4 Roosevelt Road, Taipei 10617, Taiwan (R.O.C.)
| | - Shie-Ming Peng
- Department of Chemistry, National Taiwan University No 1 Sec 4 Roosevelt Road, Taipei 10617, Taiwan (R.O.C.)
| | - Teruo Shinmyozu
- Department of Chemistry, National Taiwan University No 1 Sec 4 Roosevelt Road, Taipei 10617, Taiwan (R.O.C.)
| | - Jye-Shane Yang
- Department of Chemistry, National Taiwan University No 1 Sec 4 Roosevelt Road, Taipei 10617, Taiwan (R.O.C.)
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Chiu C, Yang J. Photoluminescent and Photoresponsive Iptycene‐Incorporated π‐Conjugated Systems: Fundamentals and Applications. CHEMPHOTOCHEM 2020. [DOI: 10.1002/cptc.201900300] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Chun‐Wei Chiu
- Department of ChemistryNational Taiwan University No 1, Sec 4, Roosevelt Rd Taipei 10617 Taiwan
| | - Jye‐Shane Yang
- Department of ChemistryNational Taiwan University No 1, Sec 4, Roosevelt Rd Taipei 10617 Taiwan
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Nikitin K, O'Gara R. Mechanisms and Beyond: Elucidation of Fluxional Dynamics by Exchange NMR Spectroscopy. Chemistry 2019; 25:4551-4589. [PMID: 30421834 DOI: 10.1002/chem.201804123] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Indexed: 12/31/2022]
Abstract
Detailed mechanistic information is crucial to our understanding of reaction pathways and selectivity. Dynamic exchange NMR techniques, in particular 2D exchange spectroscopy (EXSY) and its modifications, provide indispensable intricate information on the mechanisms of organic and inorganic reactions and other phenomena, for example, the dynamics of interfacial processes. In this Review, key results from exchange NMR studies of small molecules over the last few decades are systemised and discussed. After a brief introduction to the theory, the key types of dynamic processes are identified and fundamental examples given of intra- and intermolecular reactions, which, in turn, could involve, or not, bond-making and bond-breaking events. Following that logic, internal molecular rotation, intramolecular stereomutation and molecular recognition will first be considered because they do not typically involve bond breaking. Then, rearrangements, substitution-type reactions, cyclisations, additions and other processes affecting chemical bonds will be discussed. Finally, interfacial molecular dynamics and unexpected combinations of different types of fluxional processes will also be highlighted. How exchange NMR spectroscopy helps to identify conformational changes, coordination and molecular recognition processes as well as quantify reaction energy barriers and extract detailed mechanistic information by using reaction rate theory in conjunction with computational techniques will be shown.
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Affiliation(s)
- Kirill Nikitin
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Ryan O'Gara
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
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Affiliation(s)
- Senkai Han
- College of Chemistry; Beijing Normal University; Xinjiekouwaidajie 19 100875 Beijing P.R. China
| | - Yingying Wu
- College of Chemistry; Beijing Normal University; Xinjiekouwaidajie 19 100875 Beijing P.R. China
| | - Ran Duan
- Institute of Chemistry; Chinese Academy of Sciences; Zhongguancun North First Street 2 100190 Beijing P.R. China
| | - Hua Jiang
- College of Chemistry; Beijing Normal University; Xinjiekouwaidajie 19 100875 Beijing P.R. China
| | - Ying Wang
- College of Chemistry; Beijing Normal University; Xinjiekouwaidajie 19 100875 Beijing P.R. China
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Abstract
Despite having significant applications in building nanomachines, molecular rotors with the rotational speed modulations to multiple stages in a wide range of frequency have not yet been well established. Here, we report the discovery of a stimuli-responsive molecular rotor, the rotational speed of which in the slow-to-fast range could be modulated to at least four stages triggered by acid/base and metal cations. The rotor itself rotates rapidly at ambient or elevated temperature but displays a restricted rotation after deprotonation due to the produced intramolecular electrostatic repulsion. Subsequent addition of Li+ or Na+ cations introduces an electrostatic bridge to stabilize the transition state of the deprotonated rotor, thus giving a cation-radius-dependent acceleration of the rotation to render the rotor running at a mid-speed. All the stimuli are highly reversible. Our studies provide a conceptual approach for constructing multistage rotational-speed-changing molecular rotors, and further, the practical nanomachines. Molecular rotors with rotational speed modulation have not yet been well established. Here, the authors report a pH and metal cation triggered molecular rotor, which allows for a four stage speed modulation in the slow-to-fast frequency range.
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Gordillo MA, Soto-Monsalve M, Carmona-Vargas CC, Gutiérrez G, D'vries RF, Lehn JM, Chaur MN. Photochemical and Electrochemical Triggered Bis(hydrazone) Switch. Chemistry 2017; 23:14872-14882. [DOI: 10.1002/chem.201703065] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Indexed: 01/30/2023]
Affiliation(s)
- Mónica A. Gordillo
- Departamento de Química, Facultad de Ciencias Naturales y Exactas; Universidad del Valle, A.A; 25360 Cali Colombia
| | - Mónica Soto-Monsalve
- Instituto de Química de São Carlos; Universidade de São Paulo; 13566-590 São Carlos Brazil
| | - Christian C. Carmona-Vargas
- Departamento de Química, Facultad de Ciencias Naturales y Exactas; Universidad del Valle, A.A; 25360 Cali Colombia
| | - Gustavo Gutiérrez
- Departamento de Ciencias Farmacéuticas; Universidad Icesi, Cali; Colombia
| | - Richard F. D'vries
- Facultad de Ciencias Básicas; Universidad Santiago de Cali; Cali Colombia
| | - Jean-Marie Lehn
- Laboratoire de Chimie Supramoléculaire, Institut de Science et d'Ingéniere Supramoléculaires; Université de Strasbourg; 8 Allée Gaspard Monge 67000 Strasbourg France
| | - Manuel N. Chaur
- Departamento de Química, Facultad de Ciencias Naturales y Exactas; Universidad del Valle, A.A; 25360 Cali Colombia
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Tseng T, Lu HF, Kao CY, Chiu CW, Chao I, Prabhakar C, Yang JS. Redox-Gated Tristable Molecular Brakes of Geared Rotation. J Org Chem 2017; 82:5354-5366. [PMID: 28440080 DOI: 10.1021/acs.joc.7b00729] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
p-Bis(arylcarbonyl)pentiptycenes 2 (aryl = 4-(trifluoromethyl)phenyl) and 3 (aryl = mesityl) have been prepared and investigated as redox-gated molecular rotors. For 2, rotations about the pentiptycene-carbonyl bond (the α rotation) and about the aryl-carbonyl bond (the β rotation) are independent, and the rotation barriers are 11.3 and 9.5 kcal mol-1, respectively, at 298 K. In contrast, the α and β rotations in 3 are correlated (geared) in a 2-fold cogwheel pathway between the aryl and the pentiptycene groups with a much lower rotation barrier of 6.5 kcal mol-1 at 298 K in spite of the bulkier aryl groups. Electrochemical reduction of the neutral forms led first to radical anions (2•- and 3•-) and then to a bis(radical anion) for 22- but a dianion for 32-. The redox operations switch the independent α and β rotations in 2 into a geared rotation in both 2•- and 22- and result in a slow-fast-stop rotation mode for 2-2•--22-. The two redox states 3•- and 32- retain the geared α and β rotations and follow a fast-slow-stop mode for 3-3•--32-. Both molecular systems mimic tristable molecular brakes and display 8-9 orders of magnitude difference in rotation rate through the redox switching.
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Affiliation(s)
- Ting Tseng
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Hsiu-Feng Lu
- Institute of Chemistry, Academia Sinica , Taipei 11529, Taiwan
| | - Chen-Yi Kao
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Chun-Wei Chiu
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
| | - Ito Chao
- Institute of Chemistry, Academia Sinica , Taipei 11529, Taiwan
| | - Chetti Prabhakar
- Department of Chemistry, National Institute of Technology , Kurukshetra 136119, India
| | - Jye-Shane Yang
- Department of Chemistry, National Taiwan University , Taipei 10617, Taiwan
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Yu C, Ma L, He J, Xiang J, Deng X, Wang Y, Chen X, Jiang H. Flexible, Linear Chains Act as Baffles To Inhibit the Intramolecular Rotation of Molecular Turnstiles. J Am Chem Soc 2016; 138:15849-15852. [PMID: 27960355 DOI: 10.1021/jacs.6b10816] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In artificial molecular devices, flexible, linear chains typically exhibit very weak capability in inhibiting molecular motion. Herein, we describe the dynamic properties of a series of molecular turnstiles consisting of a rigid frame and a phenyl rotator flanked with linear alkoxymethyl substituents. The long, flexible substituents act as elastic baffles to inhibit the rotations of the rotator at medium to fast speeds on the NMR time scale. When the rotator moves slowly, the substituents become more relaxed, thus obtaining an opportunity to completely thread through the cavity of the turnstiles. These findings reveal a basic but missing correlation between steric hindrance and speed of motion for flexible, linear chains in dynamic molecular devices, thus opening up a new direction toward molecular machines with more elaborate dynamic functions.
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Affiliation(s)
- Chengyuan Yu
- Key Laboratory of Theoretical and Computational Photochemistry and Key Laboratory of Radiopharmaceuticals, Ministry of Education; College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Lishuang Ma
- Key Laboratory of Theoretical and Computational Photochemistry and Key Laboratory of Radiopharmaceuticals, Ministry of Education; College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Jiaojiao He
- Key Laboratory of Theoretical and Computational Photochemistry and Key Laboratory of Radiopharmaceuticals, Ministry of Education; College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Junfeng Xiang
- Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
| | - Xuebin Deng
- Key Laboratory of Theoretical and Computational Photochemistry and Key Laboratory of Radiopharmaceuticals, Ministry of Education; College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Ying Wang
- Key Laboratory of Theoretical and Computational Photochemistry and Key Laboratory of Radiopharmaceuticals, Ministry of Education; College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Xuebo Chen
- Key Laboratory of Theoretical and Computational Photochemistry and Key Laboratory of Radiopharmaceuticals, Ministry of Education; College of Chemistry, Beijing Normal University , Beijing 100875, China
| | - Hua Jiang
- Key Laboratory of Theoretical and Computational Photochemistry and Key Laboratory of Radiopharmaceuticals, Ministry of Education; College of Chemistry, Beijing Normal University , Beijing 100875, China
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Internal C-C Bond Rotation in Photoisomers of α-Bisimines: a Light-Responsive Two-Step Molecular Speed Regulator Based on Double Imine Photoswitching. European J Org Chem 2016. [DOI: 10.1002/ejoc.201600113] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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