1
|
Wang D, Shi C, Baumgarten M, Wang W, Liu J. Nonalternating π-System Mediated Spin Coupling in Azulene Nitronyl Nitroxide Diradicals. J Org Chem 2024; 89:12277-12285. [PMID: 39137948 DOI: 10.1021/acs.joc.4c01206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
To explore the distinctions in spin coupling between the molecular bridges of alternating and nonalternating π-systems, we synthesized a pair of isoelectronic compounds, namely, 2,6-Na-NN and 2,6-Az-NN, by utilizing naphthalene and azulene (naphthalene = Na and azulene = Az) as the bridges, respectively. Moreover, we conducted assessments to predict the coupling paths for nonalternating azulene. Variable-temperature EPR (VT-EPR) and SQUID results consistently reveal that both 2,6-Na-NN and 2,6-Az-NN exhibit antiferromagnetic coupling interactions, with coupling constants of J(2,6-Na-NN) = -22.3 cm-1 and J(2,6-Az-NN) = -30.1 cm-1, respectively. Density functional theory computations support these discoveries by revealing negative coupling constants (J < 0) and the spin densities population of the diradicals are observed to delocalize into the molecular bridges. This work suggests the most suitable coupling path for 2,6-Az-NN. In addition, we have investigated the potential spatial resistance of the diradicals in conjunction with single-crystal data. Theoretical calculations underestimating the torsion angle of the diradicals and overestimating the value of the magnetic coupling provide an explanation for this phenomenon. The final experimental results and theoretical calculations show that the 2,6-Az-NN coupling path prefers short paths.
Collapse
Affiliation(s)
- Di Wang
- Anhui Key Laboratory of Advanced Building Materials, School of Materials Science and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China
| | - Chengfang Shi
- School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Martin Baumgarten
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Wenping Wang
- School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jin Liu
- Anhui Key Laboratory of Advanced Building Materials, School of Materials Science and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China
| |
Collapse
|
2
|
Xu Y, Teng C, Wang Y, Chen D, Yin D, Yan L. Self-enhanced regulation of stable organic radicals with polypeptide nanoparticles for mild second near-infrared phototheranostics. J Colloid Interface Sci 2024; 669:578-589. [PMID: 38729006 DOI: 10.1016/j.jcis.2024.05.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 04/30/2024] [Accepted: 05/06/2024] [Indexed: 05/12/2024]
Abstract
Stable organic radicals have emerged as a promising option to enhance fluorescence quantum yield (QY), gaining traction in medical treatment due to their unique electronic transitions from the ground state (D0) to the doublet excited state (D1). We synthesized a stable dicyanomethyl radical with a NIR-II fluorescence QY of 0.86 %, surpassing many NIR-II organic dyes. Subsequently, amphiphilic polymer-encapsulated nanoparticles (NPs) containing the radical were created, achieving a NIR-II fluorescence QY of 0.32 %, facilitating high-contrast bio-imaging. These CNPPs exhibit self-enhanced photothermal properties, elevating photothermal conversion efficiency (PCE) from 43.5 % to 57.5 % under 915 nm laser irradiation. This advancement enables more efficient photothermal therapy (PTT) with lower dye concentrations and reduced laser power, enhancing both feasibility and safety. Through regular fractionated mild photothermal therapy, we observed the release of damage-associated molecular patterns (DAMPs) and an increase in cytokine expression, culminating in combined mild phototherapy (m-PTT)-mediated immunogenic cell death (ICD). Consequently, we developed an immunostimulatory tumor vaccine, showcasing a novel approach for refining photothermal agents (PTA) and optimizing the PTT process.
Collapse
Affiliation(s)
- Yixuan Xu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China. Hefei, Jinzai road 96. 230026, Anhui, PR China; Key Laboratory of Precision and Intelligent Chemistry, and Department of Chemical Physics, University of Science and Technology of China. Hefei, Jinzai road 96. 230026, Anhui, PR China
| | - Changchang Teng
- Key Laboratory of Precision and Intelligent Chemistry, and Department of Chemical Physics, University of Science and Technology of China. Hefei, Jinzai road 96. 230026, Anhui, PR China
| | - Yating Wang
- Key Laboratory of Precision and Intelligent Chemistry, and Department of Chemical Physics, University of Science and Technology of China. Hefei, Jinzai road 96. 230026, Anhui, PR China
| | - Dejia Chen
- Key Laboratory of Precision and Intelligent Chemistry, and Department of Chemical Physics, University of Science and Technology of China. Hefei, Jinzai road 96. 230026, Anhui, PR China
| | - Dalong Yin
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China. Hefei, Jinzai road 96. 230026, Anhui, PR China
| | - Lifeng Yan
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China. Hefei, Jinzai road 96. 230026, Anhui, PR China; Key Laboratory of Precision and Intelligent Chemistry, and Department of Chemical Physics, University of Science and Technology of China. Hefei, Jinzai road 96. 230026, Anhui, PR China.
| |
Collapse
|
3
|
Dai D, Zhan Q, Shi T, Wang D, Zheng Y. Spin characteristics in conjugated stable diradicals. Chem Commun (Camb) 2024; 60:8997-9006. [PMID: 39081131 DOI: 10.1039/d4cc03067b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/21/2024]
Abstract
Spin properties are intrinsic characters of electrons. Radical molecules contain unpaired electron(s), and their unique chemical and physical properties make them an ideal platform for investigating spin properties in molecular systems. Among them, the burgeoning interest in stable conjugated diradicals is attributed to their distinctive characteristics, notably the dynamic resonance structures between open-shell and closed-shell forms, the malleability of their spin states, and the profound influence of intermolecular spin-spin interactions. A deep understanding of the spin characteristics of unpaired electrons in stable conjugated diradicals provides guidance for the design, synthesis, and characterization of radical-based materials. In this review, we discuss the unique spin delocalization, spin states, and spin-spin coupling characteristics of conjugated diradicals and emphasize how to precisely control these spin characteristics to understand their role in the molecules and as functional radical materials.
Collapse
Affiliation(s)
- Dacheng Dai
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu 611731, People's Republic of China.
| | - Qian Zhan
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu 611731, People's Republic of China.
| | - Tianfang Shi
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu 611731, People's Republic of China.
| | - Dongsheng Wang
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu 611731, People's Republic of China.
| | - Yonghao Zheng
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu 611731, People's Republic of China.
- State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing 210023, People's Republic of China
| |
Collapse
|
4
|
Huang Y, Zheng X, Wu J, Gao Y, Ling Q, Lin Z. Photoinduced π-Bond breakage causing dynamic closing-opening shell transition of Z-type Diphenylmaleonitriles molecules. Nat Commun 2024; 15:6514. [PMID: 39095431 PMCID: PMC11297039 DOI: 10.1038/s41467-024-50943-4] [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: 03/14/2024] [Accepted: 07/24/2024] [Indexed: 08/04/2024] Open
Abstract
Organic molecules with dynamic covalent-bonding characteristics have attracted much attention for their important role in constructing stimulus-responsive smart materials. However, it is difficult to realize sensitive and reversible covalent bond cleavage/formation through external stimuli in the aggregated state of molecules. Herein, a series of 2,3-diphenylmaleonitriles (DPMNs) with photoinduced π-bond cleavage properties have been designed and synthesized to construct the dynamic covalent bond materials. The cis-form 2,3-diphenylmaleonitriles (Z-DPMNs) exhibit significant photochromism in both solid and solution states under ultraviolet light and visible light. The photochromism stems from the photoinduced π-bond splitting of Z-DPMNs, resulting in a transition from the closed-shell to open-shell structure. Moreover, the twisted structure and molecular stacking of Z-DPMNs, the push-pull electron effect of substituents, and the external factors including temperature and solvent polarity have important effects on the dynamic conversion of π-bonds. Based on the sensitive and reversible optical performance transformation, Z-DPMNs can be applied as safety ink in anti-counterfeiting, information encryption and storage systems. This work not only provides an approach for constructing dynamic covalent bonds but also greatly enriches stimulus-responsive materials.
Collapse
Affiliation(s)
- Yuanshan Huang
- Fujian Key Laboratory of Polymer Materials, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, China
| | | | - Junyan Wu
- Fujian Key Laboratory of Polymer Materials, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, China
| | - Yong Gao
- Fujian Key Laboratory of Polymer Materials, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, China
| | - Qidan Ling
- Fujian Key Laboratory of Polymer Materials, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, China
| | - Zhenghuan Lin
- Fujian Key Laboratory of Polymer Materials, College of Chemistry and Materials Science, Fujian Normal University, Fuzhou, China.
| |
Collapse
|
5
|
Li H, Cheng W, Lv J, Wang C. Synthesis of Fully Substituted Pyrazoles with a Dicyanomethyl Group via DBU/Lewis Acid-Mediated Annulation of D-A Cyclopropanes with Arylhydrazines. J Org Chem 2024; 89:10355-10362. [PMID: 38959522 DOI: 10.1021/acs.joc.4c00919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The efficient synthesis of fully substituted pyrazoles with a dicyanomethyl group was developed via an annulation reaction of 2-aroyl D-A cyclopropanes with arylhydrazines in the presence of DBU/AlCl3 reaction systems. This synthetic approach featured a wide range of readily available aroyl-substituted D-A cyclopropanes with diverse functional groups and a diversity of substituents on pyrazole products and had operationally simple and mild reaction conditions.
Collapse
Affiliation(s)
- Haiwen Li
- School of Chemistry and Chemical Engineering, Yangzhou University, 180 Siwangting Street, Yangzhou 225002, P. R. China
| | - Wenzhe Cheng
- School of Chemistry and Chemical Engineering, Yangzhou University, 180 Siwangting Street, Yangzhou 225002, P. R. China
| | - Jiaman Lv
- School of Chemistry and Chemical Engineering, Yangzhou University, 180 Siwangting Street, Yangzhou 225002, P. R. China
| | - Cunde Wang
- School of Chemistry and Chemical Engineering, Yangzhou University, 180 Siwangting Street, Yangzhou 225002, P. R. China
| |
Collapse
|
6
|
Lu Y, Sugita H, Mikami K, Aoki D, Otsuka H. A rational design strategy of radical-type mechanophores with thermal tolerance. Chem Sci 2023; 14:8792-8797. [PMID: 37621432 PMCID: PMC10445462 DOI: 10.1039/d3sc02991c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 07/28/2023] [Indexed: 08/26/2023] Open
Abstract
Radical-type mechanophores (RMs) are attractive molecules that undergo homolytic scission of their central C-C bond to afford radical species upon exposure to heat or mechanical stimuli. However, the lack of a rational design concept limits the development of RMs with pre-determined properties. Herein, we report a rational design strategy of RMs with high thermal tolerance while maintaining mechanoresponsiveness. A combined experimental and theoretical analysis revealed that the high thermal tolerance of these RMs is related to the radical-stabilization energy (RSE) as well as the Hammett and modified Swain-Lupton constants at the para-position (σp). The trend of the RSE values is in good agreement with the experimentally evaluated thermal tolerance of a series of mechanoresponsive RMs based on the bisarylcyanoacetate motif. Furthermore, the singly occupied molecular orbital (SOMO) levels clearly exhibit a negative correlation with σp within a series of RMs that are based on the same skeleton, paving the way toward the development of RMs that can be handled under ambient conditions without peroxidation.
Collapse
Affiliation(s)
- Yi Lu
- Department of Chemical Science and Engineering, Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku Tokyo 152-8550 Japan
| | - Hajime Sugita
- Department of Chemical Science and Engineering, Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku Tokyo 152-8550 Japan
- Sagami Chemical Research Institute 2743-1 Hayakawa Ayase Kanagawa 252-1193 Japan
| | - Koichiro Mikami
- Sagami Chemical Research Institute 2743-1 Hayakawa Ayase Kanagawa 252-1193 Japan
| | - Daisuke Aoki
- Department of Chemical Science and Engineering, Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku Tokyo 152-8550 Japan
| | - Hideyuki Otsuka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology 2-12-1 Ookayama, Meguro-ku Tokyo 152-8550 Japan
- Living Systems Materialogy (LiSM) Research Group, International Research Frontiers Initiative (IRFI), Tokyo Institute of Technology 4259 Nagatsuta-cho, Midori-ku Yokohama 226-8501 Japan
| |
Collapse
|
7
|
Badía-Domínguez I, Canola S, Hernández Jolín V, López Navarrete JT, Sancho-García JC, Negri F, Ruiz Delgado MC. Tuning the Diradical Character of Indolocarbazoles: Impact of Structural Isomerism and Substitution Position. J Phys Chem Lett 2022; 13:6003-6010. [PMID: 35737902 PMCID: PMC9272443 DOI: 10.1021/acs.jpclett.2c01325] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In this study, a set of 10 positional indolocarbazole (ICz) isomers substituted with dicyanomethylene groups connected via para or meta positions are computationally investigated with the aim of exploring the efficiency of structural isomerism and substitution position in controlling their optical and electronic properties. Unrestricted density functional theory (DFT), a spin-flip time-dependent DFT approach, and the multireference CASSCF/NEVPT2 method have been applied to correlate the diradical character with the energetic trends (i.e., singlet-triplet energy gaps). In addition, the nucleus-independent chemical shift together with ACID plots and Raman intensity calculations were used to strengthen the relationship between the diradical character and (anti)aromaticity. Our study reveals that the substitution pattern and structural isomerism represent a very effective way to tune the diradical properties in ICz-based systems with meta-substituted systems with a V-shaped structure displaying the largest diradical character. Thus, this work contributes to the elucidation of the challenging chemical reactivity and physical properties of diradicaloid systems, guiding experimental chemists to produce new molecules with desirable properties.
Collapse
Affiliation(s)
- Irene Badía-Domínguez
- Department
of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Sofia Canola
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, 40126 Bologna, Italy
| | - Víctor Hernández Jolín
- Department
of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain
| | - Juan T. López Navarrete
- Department
of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain
| | | | - Fabrizia Negri
- Department
of Chemistry “Giacomo Ciamician”, University of Bologna, 40126 Bologna, Italy
- INSTM, UdR Bologna, 40126 Bologna, Italy
| | - M. Carmen Ruiz Delgado
- Department
of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 29071 Málaga, Spain
| |
Collapse
|
8
|
Boyn JN, McNamara LE, Anderson JS, Mazziotti DA. Interplay of Electronic and Geometric Structure Tunes Organic Biradical Character in Bimetallic Tetrathiafulvalene Tetrathiolate Complexes. J Phys Chem A 2022; 126:3329-3337. [PMID: 35604797 DOI: 10.1021/acs.jpca.2c01773] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis and design of organic biradicals with tunable singlet-triplet gaps have become the subject of significant research interest, owing to their possible photochemical applications and use in the development of molecular switches and conductors. Recently, tetrathiafulvalene tetrathiolate (TTFtt) has been demonstrated to exhibit such organic biradical character in doubly ionized bimetallic complexes. In this article we use high-level ab initio calculations to interrogate the electronic structure of a series of TTFtt-bridged metal complexes, resolving the factors governing their biradical character and singlet-triplet gaps. We show that the degree of biradical character correlates with a readily measured experimental predictor, the central TTFtt C-C bond length, and that it may be described by a one-parameter model, providing valuable insight for the future rational design of TTFtt based biradical compounds and materials.
Collapse
Affiliation(s)
- Jan-Niklas Boyn
- Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Lauren E McNamara
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - John S Anderson
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - David A Mazziotti
- Department of Chemistry and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| |
Collapse
|
9
|
Yamaguchi Y, Takano R, Ishida T. Pincer-type bisnitroxide radicals involving tetramethylenedioxy and o-xylylenedioxy bridges. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.153841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
10
|
Ueda M, Kokubun M, Mazaki Y. Synthesis, structures, and properties of triskelion-shaped fluorophores bearing coumarins with nitrogen-containing donor groups. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Masafumi Ueda
- Department of Chemistry, Graduate School of Science, Kitasato University, 1-15-1, Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373
| | - Mirai Kokubun
- Department of Chemistry, Graduate School of Science, Kitasato University, 1-15-1, Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373
| | - Yasuhiro Mazaki
- Department of Chemistry, Graduate School of Science, Kitasato University, 1-15-1, Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373
| |
Collapse
|
11
|
Normal & reversed spin mobility in a diradical by electron-vibration coupling. Nat Commun 2021; 12:6262. [PMID: 34716307 PMCID: PMC8556253 DOI: 10.1038/s41467-021-26368-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 09/29/2021] [Indexed: 11/26/2022] Open
Abstract
π−conjugated radicals have great promise for use in organic spintronics, however, the mechanisms of spin relaxation and mobility related to radical structural flexibility remain unexplored. Here, we describe a dumbbell shape azobenzene diradical and correlate its solid-state flexibility with spin relaxation and mobility. We employ a combination of X-ray diffraction and Raman spectroscopy to determine the molecular changes with temperature. Heating leads to: i) a modulation of the spin distribution; and ii) a “normal” quinoidal → aromatic transformation at low temperatures driven by the intramolecular rotational vibrations of the azobenzene core and a “reversed” aromatic → quinoidal change at high temperatures activated by an azobenzene bicycle pedal motion amplified by anisotropic intermolecular interactions. Thermal excitation of these vibrational states modulates the diradical electronic and spin structures featuring vibronic coupling mechanisms that might be relevant for future design of high spin organic molecules with tunable magnetic properties for solid state spintronics. In this manuscript, Negri, Zheng, Casado et al develop a stable and flexible diradical. Using a combination of experimental and theoretical techniques, they show how heating leads to change in the electronic and spin delocalizations ocurring between quinoidal and aromatic forms, and elucidate a unique spin-vibrational coupling.
Collapse
|
12
|
Badía-Domínguez I, Peña-Álvarez M, Wang D, Pérez Guardiola A, Vida Y, Rodríguez González S, López Navarrete JT, Hernández Jolín V, Sancho García JC, García Baonza V, Nash R, Hartl F, Li H, Ruiz Delgado MC. Dynamic Covalent Properties of a Novel Indolo[3,2-b]carbazole Diradical. Chemistry 2021; 27:5509-5520. [PMID: 33474741 DOI: 10.1002/chem.202005211] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Indexed: 12/15/2022]
Abstract
This work describes the synthesis and properties of a dicyanomethylene-substituted indolo[3,2-b]carbazole diradical ICz-CN. This quinoidal system dimerises almost completely to (ICz-CN)2 , which contains two long C(sp3 )-C(sp3 ) σ-bonds between the dicyanomethylene units. The minor open-shell ICz-CN component in the solid-state mixture was identified by EPR spectroscopy. Cyclic voltammetry and UV-visible spectroelectrochemical data, as well as comparison with reference monomer ICz-Br reveal that the nature of the one-electron oxidation of (ICz-CN)2 at ambient temperature and ICz-CN at elevated temperature is very similar in all these compounds due to the prevailing localization of their HOMO on the ICz backbone. The peculiar cathodic behaviour reflects the co-existence of (ICz-CN)2 and ICz-CN. The involvement of the dicyanomethylene groups stabilizes the close-lying LUMO and LUMO+1 of (ICz-CN)2 and especially ICz-CN compared to ICz-Br, resulting in a distinctive cathodic response at low overpotentials. Differently from neutral ICz-CN, its radical anion and dianion are remarkably stable under ambient conditions. The UV/Vis(-NIR) electronic transitions in parent (ICz-CN)2 and ICz-CN and their different redox forms have been assigned convincingly with the aid of TD-DFT calculations. The σ-bond in neutral (ICz-CN)2 is cleaved in solution and in the solid-state upon soft external stimuli (temperature, pressure), showing a strong chromism from light yellow to blue-green. Notably, in the solid state, the monomeric diradical species is predominantly formed under high hydrostatic pressure (>1 GPa).
Collapse
Affiliation(s)
- Irene Badía-Domínguez
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 229071, Málaga, Spain
| | - Miriam Peña-Álvarez
- Present address: Centre for Science at Extreme Conditions & School of, Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD, UK.,MALTA-Consolider Team, Department of Physical Chemistry I, Chemistry Faculty, University Complutense of Madrid, 28040, Madrid, Spain
| | - Deliang Wang
- Key Laboratory of Synthetic and Self-assembly Chemistry for, Organic Functional Materials, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | | | - Yolanda Vida
- Departamento de Química Orgánica, Universidad de Málaga-IBIMA, Campus de Teatinos s/n, 29071, Málaga, Spain.,Centro Andaluz de Nanomedicina y Biotecnología-BIONAND, Parque Tecnológico de Andalucía, C/ Severo Ochoa 35, 29590 Campanillas, Málaga, Spain
| | - Sandra Rodríguez González
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 229071, Málaga, Spain
| | - Juan T López Navarrete
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 229071, Málaga, Spain
| | - Víctor Hernández Jolín
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 229071, Málaga, Spain
| | - Juan C Sancho García
- Department of Physical Chemistry, University of Alicante, 03080, Alicante, Spain
| | - Valentín García Baonza
- MALTA-Consolider Team and Instituto de Geociencias IGEO (CSIC-UCM), University Complutense of Madrid, 28040, Madrid, Spain
| | - Rosie Nash
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6DX, UK
| | - František Hartl
- Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6DX, UK
| | - Hongxiang Li
- Key Laboratory of Synthetic and Self-assembly Chemistry for, Organic Functional Materials, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China
| | - M Carmen Ruiz Delgado
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, 229071, Málaga, Spain
| |
Collapse
|
13
|
Kawamura A, Xie J, Boyn JN, Jesse KA, McNeece AJ, Hill EA, Collins KA, Valdez-Moreira JA, Filatov AS, Kurutz JW, Mazziotti DA, Anderson JS. Reversible Switching of Organic Diradical Character via Iron-Based Spin-Crossover. J Am Chem Soc 2020; 142:17670-17680. [PMID: 32948091 DOI: 10.1021/jacs.0c08307] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Airi Kawamura
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jiaze Xie
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jan-Niklas Boyn
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Kate A. Jesse
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Andrew J. McNeece
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Ethan A. Hill
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Kelsey A. Collins
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | | | - Alexander S. Filatov
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - Josh W. Kurutz
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - David A. Mazziotti
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| | - John S. Anderson
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, United States
| |
Collapse
|
14
|
Affiliation(s)
- Joshua P. Peterson
- Department of Chemistry, Iowa State University, 1605 Gilman
Hall, Ames, Iowa 50010, United States
| | - Arthur H. Winter
- Department of Chemistry, Iowa State University, 1605 Gilman
Hall, Ames, Iowa 50010, United States
| |
Collapse
|
15
|
Adinarayana B, Kato K, Shimizu D, Tanaka T, Furukawa K, Osuka A. Cyclophane‐Type Chlorin Dimers from Dynamic Covalent Chemistry of 2,18‐Porphyrinyl Dicyanomethyl Diradicals. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914480] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- B. Adinarayana
- Department of ChemistryGraduate School of ScienceKyoto University, Sakyo-ku Kyoto 606-8502 Japan
| | - Kenichi Kato
- Department of ChemistryGraduate School of ScienceKyoto University, Sakyo-ku Kyoto 606-8502 Japan
| | - Daiki Shimizu
- Department of ChemistryGraduate School of ScienceKyoto University, Sakyo-ku Kyoto 606-8502 Japan
| | - Takayuki Tanaka
- Department of ChemistryGraduate School of ScienceKyoto University, Sakyo-ku Kyoto 606-8502 Japan
| | - Ko Furukawa
- Center for Coordination of Research FacilitiesInstitute for Research PromotionNiigata University, Nishi-ku Niigata 950-2181 Japan
- Institute for Molecular Science 38 Nishigo-naka, Myodaiji Okazaki 444-8585 Japan
| | - Atsuhiro Osuka
- Department of ChemistryGraduate School of ScienceKyoto University, Sakyo-ku Kyoto 606-8502 Japan
| |
Collapse
|
16
|
Adinarayana B, Kato K, Shimizu D, Tanaka T, Furukawa K, Osuka A. Cyclophane-Type Chlorin Dimers from Dynamic Covalent Chemistry of 2,18-Porphyrinyl Dicyanomethyl Diradicals. Angew Chem Int Ed Engl 2020; 59:4320-4323. [PMID: 31916366 DOI: 10.1002/anie.201914480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/19/2019] [Indexed: 11/07/2022]
Abstract
2,18-Bis(dicyanomethyl)-substituted NiII porphyrin 8 and ZnII porphyrin 11 were prepared and subjected to oxidation with PbO2 in CH2 Cl2 at 298 K to give cyclophane-type chlorin dimers (9)2 and (12)2 as a consequence of double recombination of biradicals 9 and 12, respectively. Dimer (9)2 takes a syn-conformation of two distorted NiII chlorins but (12)2 takes an anti-conformation of relatively planar ZnII chlorins. At 298 K, dimer (9)2 is stable and its 1 H NMR spectrum is sharp but becomes broad at high temperature, while the 1 H NMR spectrum of (12)2 is considerably broad even at 298 K but becomes sharper at low temperature. These results indicate that the chlorin dimers dissociate to radical species, but the activation barrier of the dissociation of (12)2 is much less than that of (9)2 . The involvement of diradicals in dynamic covalent chemistry has been suggested by thermal scrambling of hetero dimer (16)2 to give homo dimers (9)2 and (15)2 .
Collapse
Affiliation(s)
- B Adinarayana
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Kenichi Kato
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Daiki Shimizu
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Takayuki Tanaka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Ko Furukawa
- Center for Coordination of Research Facilities, Institute for Research Promotion, Niigata University, Nishi-ku, Niigata, 950-2181, Japan.,Institute for Molecular Science, 38 Nishigo-naka, Myodaiji, Okazaki, 444-8585, Japan
| | - Atsuhiro Osuka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| |
Collapse
|
17
|
Peterson JP, Ellern A, Winter AH. Spin Delocalization, Polarization, and London Dispersion Forces Govern the Formation of Diradical Pimers. J Am Chem Soc 2020; 142:5304-5313. [DOI: 10.1021/jacs.0c00190] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua P. Peterson
- Department of Chemistry, Iowa State University, 1608 Gilman Hall, Ames, Iowa 50010, United States
| | - Arkady Ellern
- Department of Chemistry, Iowa State University, 1608 Gilman Hall, Ames, Iowa 50010, United States
| | - Arthur H. Winter
- Department of Chemistry, Iowa State University, 1608 Gilman Hall, Ames, Iowa 50010, United States
| |
Collapse
|
18
|
Moshniaha L, Żyła-Karwowska M, Chmielewski PJ, Lis T, Cybińska J, Gońka E, Oschwald J, Drewello T, Rivero SM, Casado J, Stępień M. Aromatic Nanosandwich Obtained by σ-Dimerization of a Nanographenoid π-Radical. J Am Chem Soc 2020; 142:3626-3635. [PMID: 31997634 PMCID: PMC7467677 DOI: 10.1021/jacs.9b13942] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
A 139-π-electron
nanographenoid radical was obtained by expanding
the periphery of a naphthalimide–azacoronene hybrid with a
methine bridge. The radical was isolated in the form of its σ-dimer,
which was shown to possess a conformationally restricted two-layer
structure both in the solid state and in solution. The dimer is cleaved
into its parent radicals when exposed to ultraviolet or visible radiation
in toluene solutions but is resistant to thermally induced dissociation.
Under inert conditions, the radicals recombine quantitatively into
the σ-dimer with observable kinetics, but they are oxidized
into a ketone derivative in the presence of atmospheric oxygen. Combined
structural, spectroscopic, and theoretical evidence shows that the
σ-dimer contains a weak C(sp3)–C(sp3) bond, but is stabilized against thermal dissociation by a very
strong dispersive interaction between the overlapping π surfaces.
Collapse
Affiliation(s)
- Liliia Moshniaha
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Marika Żyła-Karwowska
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Piotr J Chmielewski
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Tadeusz Lis
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Joanna Cybińska
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland.,PORT-Polski Ośrodek Rozwoju Technologii , ul. Stabłowicka 147 , 54-066 Wrocław , Poland
| | - Elżbieta Gońka
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Johannes Oschwald
- Department of Chemistry and Pharmacy , Friedrich-Alexander University Erlangen-Nuremberg , Egerlandstraße 3 , 91058 Erlangen , Germany
| | - Thomas Drewello
- Department of Chemistry and Pharmacy , Friedrich-Alexander University Erlangen-Nuremberg , Egerlandstraße 3 , 91058 Erlangen , Germany
| | - Samara Medina Rivero
- Departamento Quı́mica Fı́sica , Universidad de Málaga , Andalucia-Tech Campus de Teatinos s/n , 29071 Málaga , Spain
| | - Juan Casado
- Departamento Quı́mica Fı́sica , Universidad de Málaga , Andalucia-Tech Campus de Teatinos s/n , 29071 Málaga , Spain
| | - Marcin Stępień
- Wydział Chemii , Uniwersytet Wrocławski , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland
| |
Collapse
|
19
|
Peterson J, Zhang R, Winter AH. Effect of Structure on the Spin Switching and Magnetic Bistability of Solid-State Aryl Dicyanomethyl Monoradicals and Diradicals. ACS OMEGA 2019; 4:13538-13542. [PMID: 31460483 PMCID: PMC6705199 DOI: 10.1021/acsomega.9b01658] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
Stable organic radicals with switchable spin states have applications in medicine, biology, and material science. An emerging class of such spin-switchable radicals is based on dicyanomethyl radicals, which are typically thermally and air-stable species that form weakly bonded (closed-shell singlet) dimers at a lower temperature that rupture into electron paramagnetic resonance-active diradicals at a higher temperature. However, thus far, the study of these dicyanomethyl radicals has focused on their solution-phase behavior. An understanding of how chemical structure affects the solid-state spin switching behavior for these radicals is unknown. Here, we examine the solid-state spin crossover behavior of 6 monoradicals and 10 tethered diradicals and demonstrate that these species also undergo spin switching in the solid state. We find that the susceptibility for solid-state spin switching for the intermolecular dimers is weakly correlated to the solution-phase Gibbs free energies of dimerization, but no apparent correlations are seen between the solution-state free energies for the intramolecular dimerization and the solid-state behavior. Furthermore, intramolecular diradical dimers have greatly enhanced temperature-responsive behavior compared to their intermolecular counterparts. Crystalline and amorphous powders of the same radicals feature similar spin switching behavior, but the crystalline materials have slower bond-rupture kinetics at higher temperatures, suggesting that solid-state packing effects are an important kinetic consideration. An interesting feature of these systems is that, upon cooling down to room temperature after heating, some radicals remain trapped in the solids, indicating magnetic bistability, while others partially or fully return to the diamagnetic dimers. This work provides insights into how chemical structure affects spin crossover in the solid state for this new class of air-stable radicals, the knowledge of importance for the construction of dynamically responsive solid-state materials, and organic spin crossover polymers.
Collapse
|
20
|
Peterson JP, Winter AH. Solvent Effects on the Stability and Delocalization of Aryl Dicyanomethyl Radicals: The Captodative Effect Revisited. J Am Chem Soc 2019; 141:12901-12906. [PMID: 31352783 DOI: 10.1021/jacs.9b06576] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The captodative effect postulates that radicals substituted with both electron donating and accepting groups enjoy a special enhanced stabilization, a model given theoretical support by simple MO and resonance arguments. A key prediction from theory is that captodative stabilization of radicals is larger in polar solvents than in nonpolar solvents or the gas phase, which can be viewed in the resonance model as solvent stabilization of charge-separated resonance forms. Yet, several experimental studies have failed to observe a solvent effect on radical stability, casting doubt on key aspects of the captodative effect. Here, we examine in detail the effect of solvent on the stability of structurally related captodative aryl dicyanomethyl radicals. An attractive feature of these radicals is that they exist as stable steady state populations of radicals in equilibrium with their dimers, allowing us to directly characterize from experiment their thermodynamic stabilities and spin delocalization in solvents of varying polarity. In contrast to the prior studies, we find that captodative radicals are indeed stabilized by polar solvents, as measured by a shift in the radical-dimer association constants by up to 100-fold toward the radical upon going from nonpolar toluene to more polar DMF. Moreover, in polar solvents, the spin is shifted onto the donor substituent and away from the benzylic carbon. Within the resonance model, these results can be explained by the increased contributions of the zwitterionic resonance structures to the overall hybrid. These results provide experimental support to a key prediction from theory that had previously been dismissed.
Collapse
Affiliation(s)
- Joshua P Peterson
- Department of Chemistry , Iowa State University , 1608 Gilman Hall , Ames , Iowa 50010 , United States
| | - Arthur H Winter
- Department of Chemistry , Iowa State University , 1608 Gilman Hall , Ames , Iowa 50010 , United States
| |
Collapse
|
21
|
Varejão JOS, Varejão EVV, Fernandes SA. Synthesis and Derivatization of Julolidine: A Powerful Heterocyclic Structure. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900398] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Jodieh Oliveira Santana Varejão
- Grupo de Química Supramolecular e Biomimética (GQSB); Departamento de Química; Universidade Federal de Viçosa; 36570-900 Brazil
| | - Eduardo Vinícius Vieira Varejão
- Grupo de Química Supramolecular e Biomimética (GQSB); Departamento de Química; Universidade Federal de Viçosa; 36570-900 Brazil
| | - Sergio Antonio Fernandes
- Grupo de Química Supramolecular e Biomimética (GQSB); Departamento de Química; Universidade Federal de Viçosa; 36570-900 Brazil
| |
Collapse
|
22
|
Adinarayana B, Shimizu D, Furukawa K, Osuka A. Stable radical versus reversible σ-bond formation of (porphyrinyl)dicyanomethyl radicals. Chem Sci 2019; 10:6007-6012. [PMID: 31360409 PMCID: PMC6566382 DOI: 10.1039/c9sc01631g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 05/13/2019] [Indexed: 11/21/2022] Open
Abstract
(Porphyrinyl)dicyanomethyl radicals were produced by oxidation of dicyanomethyl-substituted porphyrins with PbO2. These radicals constitute a rare example displaying stable radical versus dynamic covalent chemistry (DCC) depending upon the substitution position of the dicyanomethyl radical. meso-Dicyanomethyl-substituted radicals exist as stable monomeric species and do not undergo any dimerization processes either in the solid state or in solution. In contrast, β-dicyanomethyl-substituted radicals are isolated as σ-dimers that are stable in the solid-state but display reversible σ-dimerization behavior in solution; monomeric radical species exist predominantly at high temperatures, while σ-dimerization is favoured at low temperatures. This dynamic behaviour has been confirmed by variable-temperature 1H NMR, UV-vis and EPR measurements. The structures of the stable radical and σ-dimer have been revealed by single-crystal X-ray diffraction analysis. The observed different reactivities of the two (porphyrinyl)dicyanomethyl radicals have been rationalized in terms of their spin delocalization behaviours.
Collapse
Affiliation(s)
- B Adinarayana
- Department of Chemistry , Graduate School of Science , Kyoto University , Sakyo-ku , Kyoto 606-8502 , Japan .
| | - Daiki Shimizu
- Department of Chemistry , Graduate School of Science , Kyoto University , Sakyo-ku , Kyoto 606-8502 , Japan .
| | - Ko Furukawa
- Centre for Instrumental Analysis , Niigata University , Nishiku , Niigata , 950-2181 , Japan
| | - Atsuhiro Osuka
- Department of Chemistry , Graduate School of Science , Kyoto University , Sakyo-ku , Kyoto 606-8502 , Japan .
| |
Collapse
|
23
|
Adinarayana B, Shimizu D, Osuka A. Stable (BIII
-Subporphyrin-5-yl)dicyanomethyl Radicals. Chemistry 2019; 25:1706-1710. [DOI: 10.1002/chem.201805601] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Bellamkonda Adinarayana
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| | - Daiki Shimizu
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| | - Atsuhiro Osuka
- Department of Chemistry; Graduate School of Science; Kyoto University; Sakyo-ku Kyoto 606-8502 Japan
| |
Collapse
|