論文 - 忍久保　洋

Highly Electron‐Donating Antiaromatic N,N′‐Dimethyldiazaporphyrins via Reductive Dimethylation 招待有り 査読有り 国際誌

Kohei Ohtake, Hideaki Takano, Hiroshi Shinokubo

ChemistryEurope   3 巻   頁： e20250010   2025年6月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

Ni(II) N,N′‐dimethyl‐5,15‐diazaporhyrins are efficiently prepared through reductive dimethylation of 5,15‐diazaporphyrin Ni(II) complexes with sodium dispersion in the presence of dimethyl sulfate. The obtained reduced diazaporphyrins exhibit highly upfield‐shifted ¹H NMR spectra and narrowed HOMO–LUMO gaps originating from their distinct antiaromatic nature. The electrochemical analysis reveals their highly electron‐donating property, which leads to the formation of a charge transfer (CT) complex with tetracyanoquinodimethane (TCNQ) as an electron acceptor. The CT complex of Ni(II) N,N′‐dimethyl‐10,20‐diphenyl‐5,15‐diazaporphyrin with TCNQ exhibits alternate π‐stacking orientation in the solid state. N,N′‐Dimethyl‐5,15‐diazaporphyrins also interact with C₆₀ in the solid state to yield cocrystals.

DOI： 10.1002/ceur.202500109

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Chiral Aromatic Micelles as Chiroptical Host Tools for Large Metallodyes in Water 査読有り 国際誌

Hashimoto, Y; Tanaka, Y; Liu, SY; Shinokubo, H; Yoshizawa, M

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   147 巻 ( 26 ) 頁： 23060 - 23067   2025年6月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the American Chemical Society  

In contrast to abundant aliphatic chiral cavities in nature, synthetic chiral cavities formed by self-assembly of aromatic subunits are quite rare, particularly providing an ability in induced chirality. Here, we report new chiral aromatic micelles capable of inducing the optical chirality of large metallodyes upon encapsulation. The aromatic micelle, with a core diameter of ∼3 nm, forms from axially chiral amphiphiles featuring a bent mesityl-substituted BINOL framework. Unlike alkyl and aromatic micelles reported previously, the obtained micelle emits strong fluorescence (Φ<inf>F</inf> > 40%) through the aggregation-induced emission effect in water. The adaptable chiral cavity of the micelle efficiently encapsulates several kinds of achiral metallodyes, such as metalated porphyrins and norcorroles, to afford aqueous host-guest composites, displaying efficient dye-based induced chirality through multiple CH-π interactions. Remarkably, the chirality induction of metallophthalocyanine, bearing a completely planar framework, and its stacked dimer can also be demonstrated (up to |g<inf>abs</inf>| = 2.4 × 10^-3) in the cavity under ambient aqueous conditions. To the best of our knowledge, the present aromatic micelles are the first host tools to induce the chiral properties of common to rare metallodyes, without additional covalent functionalizations. The chiroptical properties of the obtained host-guest composites are further tunable (i.e., 0.1- to 1.6-fold intensity) upon thermal stimuli in an irreversible fashion without disassembly.

DOI： 10.1021/jacs.5c06179

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Oxidation of Platina(II)corrole to Platina(IV)corrole 査読有り 国際誌

Kato, S; Miwa, K; Takano, H; Shinokubo, H

INORGANIC CHEMISTRY   64 巻 ( 22 ) 頁： 10916 - 10922   2025年5月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Inorganic Chemistry  

Recently, the aromaticity and antiaromaticity of organometallacycles have received much attention to understand the cyclic electronic delocalization through d orbitals on the metal center. Here, we prepared a Pd(II) platina(II)corrole bipyridyl complex, which was converted to the corresponding stable Pt(IV) complex upon oxidation with iodobenzene dichloride. Oxidation of the platinum center did not result in the C-C bond formation between two pyrrole units via reductive elimination. The X-ray diffraction analysis of these complexes elucidated their nonplanar molecular structures. The nonaromatic nature of platina(II)- and platina(IV)corroles was revealed by ¹H NMR analysis and NICS calculations.

DOI： 10.1021/acs.inorgchem.5c00942

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Rolling two-dimensional covalent organic framework (COF) sheets into one-dimensional electronic and proton-conductive nanotubes 査読有り 国際共著 国際誌

Li, ZW; Paitandi, RP; Tsutsui, Y; Matsuda, W; Nobuoka, M; Chen, B; Ghosh, S; Tanaka, T; Suda, M; Zhu, T; Kageyama, H; Miyake, Y; Shinokubo, H; Takagi, M; Shimazaki, T; Tachikawa, M; Suzuki, K; Kaji, H; Ando, Y; Ezaki, T; Seki, S

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   122 巻 ( 16 ) 頁： e2424314122   2025年4月

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of the National Academy of Sciences of the United States of America  

Mimicking the interconvertible carbon allotropes of 2-dimensional (2D) graphene and 1-dimensional (1D) carbon nanotubes (CNTs), herein we report the in situ transformation of 2D π-conjugated covalent organic frameworks (COFs) sheet into 1D nanotubular structures via self-assembly the sheets at solvent interfaces. The facile “roll-sheets” self-assembly resulted in coaxial nanotubes with uniform cross-sectional diameter, which was realized for diazapyrene-based COFs but not for the corresponding pyrene COF, although both possess similar chemical structures. Upon replacing the carbon atoms at 2,7-positions of pyrene with nitrogen, contrasting optical and electronic properties were realized, reflecting the rolled structure of the conjugated 2D sheets. The nanotubes exhibited concerted electronic- and proton-conducting nature with stable conducting pathways at ambient conditions. The nitrogen centers act simultaneously as the site for charge carrier doping and proton acceptors, as evidenced by the high photo- and electrical conductivity, as well as the record proton conductivity (σ = 1.98 S cm⁻¹) results. The present diazapyrene-based 1D nanotubular COF serves as a unique materials platform with electronic conduction in the wall and proton conduction in the core, respectively.

DOI： 10.1073/pnas.2424314122

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Effect of structural bending on the photophysical properties of perylene bisimide 招待有り 査読有り 国際誌

Sotome, H; Higashi, M; Tanaka, Y; Shinokubo, H; Kobori, Y; Fukui, N

JOURNAL OF CHEMICAL PHYSICS   162 巻 ( 11 ) 頁： 114305   2025年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Chemical Physics  

The effect of nonplanarity on the electronic properties of π-systems has been difficult to study systematically because of the limited availability of suitable model compounds. Our group recently synthesized a series of end-to-end bent perylene bisimide (PBI) cyclophanes, whose degree of bending is adjustable by modifying the internal alkyl tethers. Herein, we subjected these bent PBI derivatives to theoretical calculations and time-resolved spectroscopy. The current study has offered rational explanations for several unique photophysical characteristics of bent PBIs: (1) the redshifts of the S<inf>0</inf>-S<inf>1</inf> transitions, (2) the decrease in extinction coefficients, (3) the broadening of spectral shapes, and (4) the suppression of nonradiative decay processes. Furthermore, the investigation of the S<inf>1</inf> states and radical anions has revealed that structural bending also substantially alters the energy levels of upper molecular orbitals such as LUMO+2.

DOI： 10.1063/5.0255756

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Captodative Approach to Stable Nitrogen-Centered Radicals, Anions, and Cations Exhibiting Near-Infrared Electrochromism 査読有り 国際共著 国際誌 Open Access

Tajima, K; Bucher, C; Shimizu, D; Fukui, N; Shinokubo, H

JACS AU   5 巻 ( 3 ) 頁： 1421 - 1428   2025年3月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Jacs Au  

Redox interconversion of the oxidation state of nitrogen via hydrogenation and dehydrogenation represents a powerful strategy for designing stimuli-responsive materials. In sharp contrast, the interconversion of nitrogen centers via electron transfer has been underexplored due to the high reactivity of aminyl radicals (R<inf>2</inf>N^•), amide anions (R<inf>2</inf>N^-), and nitrenium cations (R<inf>2</inf>N⁺). Herein, we demonstrate that a captodative approach, i.e., the dual incorporation of electron-donating and electron-accepting units, is effective to stabilize these three classes of nitrogen-centered species within the same molecular scaffold. We synthesized a 9,10-dihydroacridine derivative with nitrogen-doping at the 9-position and imide-substitution at the 2,3- and 6,7-positions. This molecule afforded an aminyl radical upon hydrogen abstraction with PbO<inf>2</inf>. The injection or removal of an electron of the aminyl radical furnished the corresponding amide anion and nitrenium cation, respectively. The aminyl radical, amide anion, and nitrenium cation exhibit significant stability under ambient conditions. Redox interconversion between the amide anion and nitrenium cation results in a drastic change in near-infrared (NIR) absorption due to switching of the local aromaticity of the central six-membered ring. These attractive properties lead to electrochromism in the NIR region (up to 1050 nm) between the closed-shell species.

DOI： 10.1021/jacsau.5c00037

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その他リンク： https://doi.org/10.1021/jacsau.5c00037

Synthesis and Properties of Donor-Acceptor-Type Cyclobisbiphenylenecarbonyls 査読有り 国際誌

Nishimoto, E; Ikai, T; Shinokubo, H; Fukui, N

CHEMISTRY-A EUROPEAN JOURNAL   31 巻 ( 15 ) 頁： e202404194   2025年1月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemistry - A European Journal  

The scalable synthesis of figure-eight π-systems is challenging for the conventional bottom-up approach. We have recently reported that the oxidative inner-bond cleavage of commercially available dibenzo[g,p]chrysene efficiently furnishes a figure-eight π-acceptor, cyclobisbiphenylenecarbonyl (CBBC), in large quantity. Furthermore, its donor–acceptor-type derivative with four N-carbazolyl substituents at the meta-positions of the carbonyl groups exhibited thermally activated delayed fluorescence (TADF) and circularly polarized luminescence (CPL) with a high |gCPL| value of 1.0×10−2. Herein, we synthesized nine donor–acceptor-type CBBC derivatives by changing the donor substituents and their positions. Compared to previously reported carbazole-substituted CBBC, tetramethylcarbazole- and 9,10-dihydro-9,9-dimethylacridine-substituted derivatives exhibited enhanced emission quantum yields and accelerated reverse intersystem crossing. The functionalization of the para-positions of the carbonyl groups resulted in better tunability of emission colors rather than meta-functionalization, whose color variation ranges from light blue to red. The incorporation of bulky substituents at the meta-positions of the carbonyl groups induced the conformational change to a distorted ring structure. Investigation of the substituent effect on the chiroptical properties revealed that the introduction of less bulky donor units such as carbazole at the meta-positions of the carbonyl groups is effective in achieving high |gCPL| values.

DOI： 10.1002/chem.202404194

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その他リンク： https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202404194

Development of Stable π -Conjugated Hydrocarbons with Narrow HOMO-LUMO Gaps 査読有り 国際誌

Fukui N., Shinokubo H.

Yuki Gosei Kagaku Kyokaishi Journal of Synthetic Organic Chemistry   83 巻 ( 5 ) 頁： 455 - 463   2025年

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Yuki Gosei Kagaku Kyokaishi Journal of Synthetic Organic Chemistry  

Carbon and hydrogen are fundamental components of organic molecules. Various functional π - systems have been created via the structural modification of conventional π -conjugated hydrocarbons. Novel π -conjugated hydrocarbon skeletons with attractive electronic structures are a source of novel functional materials. Notably, π -conjugated hydrocarbons with a narrow HOMO-LUMO gap are attractive research targets. Hydrocarbons with antiaromaticity or diradical character often exhibit narrow HOMO-LUMO gaps. However, these molecules are inherently reactive, thus requiring kinetic stabilization by sterically hindered peripheral substituents. This article describes the synthesis and properties of as-indaceno[3,2,1,8,7,6-ghijklm]terrylene, indeno[1,2,3,4-pqra]perylene, and its π - extended derivatives. These π -conjugated hydrocarbons are sufficiently stable under ambient conditions despite their narrow HOMO-LUMO gaps.

DOI： 10.5059/yukigoseikyokaishi.83.455

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Development of Stable π-Conjugated Hydrocarbons with Narrow HOMO-LUMO Gaps 査読有り 国際誌

Fukui, N; Shinokubo, H

JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN   83 巻 ( 5 ) 頁： 455 - 463   2025年

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

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Diradical character view of energy stabilization in π-stacked dimers of antiaromatic molecules 査読有り 国際誌 Open Access

Sugimori, R; Kishi, R; Shinokubo, H; Kitagawa, Y

CHEMISTRY LETTERS   53 巻 ( 12 ) 頁： upae224   2024年12月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemistry Letters  

We theoretically examined the energy stabilization mechanism of closely π-stacked dimers of antiaromatic molecules from the viewpoint of diradical character (y). Quantum chemical calculations for π-stacked dimer models of cyclobutadienes and Ni(II) norcorroles revealed that the balance between the destabilization due to structural deformation in each monomer and the stabilization due to intermolecular orbital interaction between 4nπ systems and dispersion force determined the stabilization in the π-dimer structures.

DOI： 10.1093/chemle/upae224

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その他リンク： https://doi.org/10.1093/chemle/upae224

Catalytic Construction of Stereogenic Boron Center on BODIPY via Enantioselective Suzuki–Miyaura Coupling 査読有り 国際誌

Aiko Kondo, Hideaki Takano, Hiroshi Shinokubo

Chemistry Letters     2024年11月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/chemle/upae218

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Bowl-Shaped Anthracene-Fused Antiaromatic Ni(II) Norcorrole: Synthesis, Structure, Assembly with C60, and Photothermal Conversion 査読有り 国際誌

Wang, KS; Ghosh, A; Shimizu, D; Takano, H; Ishida, M; Kishi, R; Shinokubo, H

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION   64 巻 ( 7 ) 頁： e202419289   2024年11月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Angewandte Chemie - International Edition  

The synthesis of bowl-shaped antiaromatic molecules is challenging because the molecular distortion further destabilizes these already inherently reactive molecules. Here, we report the synthesis and properties of bowl-shaped fused anthrylnorcorroles that exhibit near-infrared (NIR) absorption reaching 1900 nm. The oxidation of meso-anthryldibromodipyrrin provides fused anthryldibromodipyrrin, which was converted to the fused mono- and bisanthrylnorcorroles through Ni(0)-mediated intramolecular coupling with a bis(dibromodipyrrin) Ni(II) complex. Single-crystal X-ray diffraction analyses revealed bowl-shaped structures for the fused mono- and bisanthrylnorcorroles, which enables them to act as suitable receptors for C60 with bonding constants of 2.89×103 M−1 and 1.59×103 M−1, respectively. The formation of a 1 : 1 complex between the fused monoanthrylnorcorrole and C60 was confirmed by single-crystal X-ray diffraction analysis. The effective expansion of the π-conjugation through the triple fusion of the norcorrole with the anthracene units substantially enhances the near-infrared absorption bands, which endows these anthrylnorcorroles with effective photothermal conversion.

DOI： 10.1002/anie.202419289

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その他リンク： https://onlinelibrary.wiley.com/doi/10.1002/anie.202419289

Zig-zag-fused π-extended BODIPYs via gold-catalysed cycloisomerisation 招待有り 査読有り 国際誌

Ohashi, F; Takano, H; Shinokubo, H

Chemical Communications   60 巻 ( 88 ) 頁： 12892 - 12895   2024年11月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Communications  

π-Extension of the BODIPY core is an effective strategy to modulate the physical properties of BODIPYs. However, π-extension on the zig-zag edge of BODIPYs remains unexplored. Here, we disclose the synthesis of zig-zag-fused BODIPYs through gold-catalysed cycloisomerisation. The obtained BODIPYs show fascinating photophysical properties including near-infrared absorption and emission.

DOI： 10.1039/d4cc04416a

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Synthesis and electron-transporting properties of phenazine bisimides 査読有り 国際誌

Tajima, K; Moribe, T; Matsuo, K; Yamada, H; Seki, S; Yokokura, S; Shimada, T; Fukui, N; Shinokubo, H

JOURNAL OF MATERIALS CHEMISTRY C   13 巻 ( 2 ) 頁： 655 - 662   2024年10月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Materials Chemistry C  

The dual incorporation of imide substituents and imine-type nitrogen atoms into π-systems represents an emerging guideline for the design of robust and high-performance n-type semiconductors. Herein, we have adapted this strategy to a simple molecular motif: anthracene, and thus synthesized phenazine bisimides (PzBIs). PzBIs exhibit superior electron affinity compared to anthracene bisimide and phenazine due to the presence of two types of functional electron-withdrawing units. The existence of imine-type nitrogen atoms in PzBI leads to the formation of two-dimensionally extended brickwork arrangements while anthracene bisimide forms one-dimensionally slipped-stacked arrays. Consequently, the electron mobility of the vacuum-deposited film of N,N′-dicyclohexyl PzBI is ten times higher than that of the corresponding anthracene bisimide. Furthermore, the OFET device of N,N′-bisheptafluorobutyl PzBI exhibits good air persistency, and its intrinsic electron mobility has been estimated to be approximately 0.7 cm2 V−1 s−1 by the time-resolved microwave conductivity measurement. The current study demonstrates that the dual incorporation strategy endows even a simple and small π-system with good performance as an n-type semiconductor.

DOI： 10.1039/d4tc03306j

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Synthesis of four regioisomeric Ni(II) azacorroles via oxidative ring-expansion of prefunctionalised norcorroles 査読有り 国際共著 国際誌

Li, S; Zhang, SW; Ohtake, K; Shinokubo, H; Li, XF

ORGANIC CHEMISTRY FRONTIERS   11 巻 ( 20 ) 頁： 5928 - 5937   2024年10月

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Organic Chemistry Frontiers  

We explored the synthesis of four regioisomeric formylated and brominated azacorroles via oxidative insertion of prefunctionalised Ni(ii) norcorroles. We also found that the reaction of Ni(ii) azacorroles with the Vilsmeier reagent afforded 2- and 3-formylazacorroles. The structures of all the products were characterised thoroughly by high-resolution mass spectrometry, NMR and UV-vis absorption spectroscopy together with X-ray diffraction analysis. The synthesis of four regioisomers of formyl- and bromoazacorroles allowed a detailed study of the substituent effect depending on the position of the functionality.

DOI： 10.1039/d4qo01415d

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Inner-Bond-Cleavage Approach to Figure-Eight Macrocycles from Planar Aromatic Hydrocarbons 査読有り 国際共著 国際誌

Yoshina, R; Hirano, J; Nishimoto, E; Sakamoto, Y; Tajima, K; Minabe, S; Uyanik, M; Ishihara, K; Ikai, T; Yashima, E; Omine, T; Ishiwari, F; Saeki, A; Kim, J; Oh, J; Kim, D; Liu, GT; Yasuda, T; Shinokubo, H; Fukui, N

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   146 巻 ( 43 ) 頁： 29383 - 29390   2024年9月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the American Chemical Society  

Figure-eight-shaped nonplanar π-systems adopt distinctive chiral D2-symmetric structures, which are ideal for realizing efficient circularly polarized luminescence (CPL). However, the short-step and enantioselective synthesis of figure-eight π-systems represents a considerable challenge for the conventional bottom-up synthetic strategy. Herein, we report that the oxidative cleavage of the internal double bond of a commercially available polycyclic aromatic hydrocarbon, i.e., dibenzo[g,p]chrysene (DBC), catalytically affords a figure-eight electron-accepting macrocycle, i.e., cyclobisbiphenylenecarbonyl (CBBC), with high scalability (up to 3.3 g) and excellent enantioselectivity (94% ee). This inner-bond-cleavage approach also applies to larger PAHs, affording highly distorted molecular frameworks that comprise two figure-eight subunits. Furthermore, we demonstrate that the peripheral functionalization of CBBC with carbazole afforded donor-acceptor-type emitter, which shows thermally activated delayed fluorescence and emits CPL with a g value of 1.0 × 10-2. This g value is ten times higher than those of previously reported chiral TADF-active emitters for circularly polarized organic light-emitting diodes. These results demonstrate that oxidative inner-bond cleavage is a powerful synthetic strategy for creating innovative materials that incorporate molecules with figure-eight structures.

DOI： 10.1021/jacs.4c07985

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An n-type semiconducting diazaporphyrin-based hydrogen-bonded organic framework 査読有り 国際誌

Sakurai, T; Tanabe, T; Iguchi, H; Li, ZW; Matsuda, W; Tsutsui, Y; Seki, S; Matsuda, R; Shinokubo, H

CHEMICAL SCIENCE   15 巻 ( 32 ) 頁： 12922 - 12927   2024年8月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Science  

Significant effort has been devoted to the development of materials that combine high electrical conductivity and permanent porosity. This paper discloses a diazaporphyrin-based hydrogen-bonded organic framework (HOF) with porosity and n-type semiconductivity. A 5,15-diazaporphyrin Ni(ii) complex with carboxyphenyl groups at the meso positions afforded a HOF due to hydrogen-bonding interactions between the carboxy groups and meso-nitrogen atoms. The thermal and chemical stabilities of the HOF were examined using powder X-ray diffraction analysis, and the charge-carrier mobility was determined to be 2.0 × 10−7 m2 V−1 s−1 using the flash-photolysis time-resolved microwave conductivity (FP-TRMC) method. An analogous diazaporphyrin, which does not form a HOF, exhibited mobility that was 20 times lower. The results presented herein highlight the crucial role of hydrogen-bonding networks in achieving conductive pathways that can tolerate thermal perturbation.

DOI： 10.1039/d4sc03455d

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その他リンク： https://doi.org/10.1039/D4SC03455D

Radical reactivity of antiaromatic Ni(II) norcorroles with azo radical initiators 招待有り 査読有り 国際誌

Shafie, SA; Nozawa, R; Takano, H; Shinokubo, H

BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY   20 巻   頁： 1967 - 1972   2024年8月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Beilstein Journal of Organic Chemistry  

Norcorrole is a stable 16π-antiaromatic porphyrinoid that exhibits characteristic reactivities and physical properties. Here, we disclose the reaction of Ni(II) norcorroles with alkyl radicals derived from azo radical initiators. The radical selectively attacked the distal α-position relative to the meso-position to construct a nonaromatic bowl-shaped structure. The photophysical and electrochemical properties of the obtained radical adducts were compared to those of the parent Ni(II) norcorrole. The radical reactivity of Ni(II) norcorroles was investigated by density functional theory (DFT) calculations.

DOI： 10.3762/bjoc.20.172

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Ultrafine Spatial Modulation of Diazapyrene-Based Two-Dimensional Conjugated Covalent Organic Frameworks 査読有り 国際共著 国際誌

Li, ZW; Tsuneyuki, T; Paitandi, RP; Nakazato, T; Odawara, M; Tsutsui, Y; Tanaka, T; Miyake, Y; Shinokubo, H; Takagi, M; Shimazaki, T; Tachikawa, M; Suzuki, K; Kaji, H; Ghosh, S; Seki, S

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY   146 巻 ( 33 ) 頁： 23497 - 23507   2024年8月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of the American Chemical Society  

Tailormade bottom-up synthesis of covalent organic frameworks (COFs) from various functional building blocks offer not only tunable topology and pore size but also multidimensional properties. High crystallinity is one of the prerequisites for their structures and associated physicochemical properties. Among different π-conjugated motifs for constructing COFs, pyrene-based tetragonal structures are effective in achieving highly ordered and crystalline states. In the present research, we demonstrated that the substitution of pyrene with 2,7-diazapyrene produces nearly “flat” structures of two-dimensional (2D) COF layers by controlling the torsional angle of linker molecules. Featuring finite pore diameters and excellent thermodynamic stability of ∼500 °C, ordered face-to-face (slipped AA) stacking arrangements were produced. Extended electrical conjugation spanning 2D frames with modest optical bandgaps (Eg) of ∼2.1 eV shows the planar character of diazapyrene-based COFs. The stacking of the conjugated 2D frames with small Eg values is also beneficial for the formation of highly stable conducting pathways in the crystalline state, which was confirmed by the results of the microwave conductivity measurements. Nitrogen centers in diazapyrene units also play a key role as the active sites for proton transfer, and the maximum proton conductivity of σ = 10-2 S cm-1 was achieved along the cocontinuous nanopore structures surrounded by the active sites. Results show that tetragonal COFs based on diazapyrene can be used as a highly crystalline two-dimensional material with special electrical and proton-conducting capabilities.

DOI： 10.1021/jacs.4c07091

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Homochiral and Heterochiral Self-Sorting Assemblies of Antiaromatic Ni(II) Norcorrole Dimers 査読有り 国際誌

Liu, SY; Li, S; Ukai, S; Nozawa, R; Fukui, N; Sugimori, R; Kishi, R; Shinokubo, H

CHEMISTRY-A EUROPEAN JOURNAL   30 巻 ( 39 ) 頁： e202400292   2024年7月

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemistry - A European Journal  

Recently, π–π stacked antiaromatic π-systems have received considerable attention because they can exhibit stacked-ring aromaticity due to substantial intermolecular orbital interactions. Here, we report three antiaromatic norcorrole dimers that self-assemble to form supramolecular architectures through chiral self-sorting. A 2,2’-linked norcorrole dimer with 3,5-di-tert-butylphenyl groups forms a π-stacked dimer both in solid and solution states via homochiral self-sorting. Its association constant in solution is (3.6±1.7)×105 M−1 at 20 °C. In the solid state, 3,3’-linked norcorrole dimers with 3,5-di-tert-butylphenyl and phenyl groups afford macrocyclic and helical supramolecular assemblies via heterochiral and homochiral self-sorting, respectively. Notably, the subtle modification in the substituent resulted in a complete change in the structure of the aggregates and the chiral self-sorting mode. The present findings demonstrate that structural manipulation in antiaromatic monomer units leads to the formation of various supramolecular assemblies on the basis of the attractive interactions between antiaromatic π-systems.

DOI： 10.1002/chem.202400292

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