DOI： 10.1021/prechem.3c00121

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Publishing type：Research paper (scientific journal)  

DOI： 10.1093/chemle/upad037

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Publishing type：Research paper (scientific journal)  

DOI： 10.1039/d3cc04887j

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PubMed

DOI： 10.1002/anie.202310613

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PubMed

Publishing type：Research paper (scientific journal)  

DOI： 10.1002/ange.202310613

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/prechem.3c00083

Publishing type：Research paper (scientific journal)   Publisher：Georg Thieme Verlag KG  

Abstract

A novel structurally constrained nanobelt, methylene-bridged [6]cyclo-2,6-naphthylene ([6]MCN), has been synthesized by the nickel-mediated intramolecular aryl–aryl coupling of a triflated prism[6]arene. The structural and electronic properties of [6]MCN were revealed through NMR studies and photophysical measurements. In contrast to methylene-bridged [6]cycloparaphenylene, our previously synthesized benzene-based analogue, [6]MCN has a low strain energy (77.4 kcal·mol–1) and displays bright fluorescence (Φ = 0.20).

DOI： 10.1055/a-2009-8219

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/jacs.3c02788

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PubMed

Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/jacs.2c13208

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PubMed

DOI： 10.1016/j.tet.2022.132907

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Aromatic polymers are the first-choice platform for current organic materials due to their distinct optical, electronic, and mechanical properties as well as their biocompatibility. However, bare aromatic polymer backbones tend to strongly aggregate, rendering them essentially insoluble in organic solvent. While the typical solution is to install many solubilizing substituents on the backbones, this often provokes undesired property changes. Herein, we report the synthesis of bare aromatic polymers enabled by a dendrimer support. An initiator arene containing a diterpenoid-based dendrimer undergoes Pd-catalyzed polymerization with monomers bearing no solubilizing substituents to furnish bare aromatic polymers such as polythiophenes and poly(para-phenylene)s. The high solubility of dendrimer-ligated polymers allows not only the unveiling of the properties of unsubstituted π-conjugated backbone, but also mild release of dendrimer-free aromatic polymers and even transfer of aromatic polymers to other materials, such as silica gel and protein, which may accelerate the creation of hybrid materials nowadays challenging to access.

DOI： 10.1038/s41467-022-33100-7

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PubMed

Other Link： https://www.nature.com/articles/s41467-022-33100-7

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

Nitrogen-doped nonalternant aromatic belt was synthesized via palladium-catalyzed six-fold annulative double N-arylation reaction. The highly symmetric structure and multistep oxidation behavior of the N-belt were confirmed.

DOI： 10.1039/d2sc02647c

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PubMed

Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Perfluorinated aromatic compounds, the so-called perfluoroarenes, are widely used in materials science owing to their high electron affinity and characteristic intermolecular interactions. However, methods to synthesize highly strained perfluoroarenes are limited, which greatly limits their structural diversity. Herein, we report the synthesis and isolation of perfluorocycloparaphenylenes (PFCPPs) as a class of ring-shaped perfluoroarenes. Using macrocyclic nickel complexes, we succeeded in synthesizing PF[n]CPPs (n = 10, 12, 14, 16) in one-pot without noble metals. The molecular structures of PF[n]CPPs (n = 10, 12, 14) were determined by X-ray crystallography to confirm their tubular alignment. Photophysical and electrochemical measurements revealed that PF[n]CPPs (n = 10, 12, 14) exhibited wide HOMO–LUMO gaps, high reduction potentials, and strong phosphorescence at low temperature. PFCPPs are not only useful as electron-accepting organic materials but can also be used for accelerating the creation of topologically unique molecular nanocarbon materials.

DOI： 10.1038/s41467-022-31530-x

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PubMed

Other Link： https://www.nature.com/articles/s41467-022-31530-x

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

The discovery and creation of new forms of carbon have always transformed the scientific landscape. For example, the discoveries of fullerenes, carbon nanotubes (CNTs), and graphenes have opened doors to the science of nanometersized carbon allotropes, otherwise known as nanocarbons. Since then, researchers worldwide have unveiled their outstanding physical and chemical properties, and a number of applications and technologies have arisen in not only materials science but also biological research fields. The synthesis and study of this privileged class of "single-molecule" compounds has become one of the most engaging subjects in chemistry and holds huge promise to establish new fields in molecular science. However, there have been huge gaps between established small-molecule chemistry and nanocarbon science. In the particular case of CNTs, it is still not possible to access structurally uniform CNTs. Although a wide range of synthetic methods have been reported, CNTs are generally accessed as a mixture of various structures. One logical strategy to achieve full synthetic control over CNTs is to build up from a template molecule with structural precision (the so-called "growth-from-template" strategy), where a short CNT segment molecule represents an initial synthetic target. To this end, organic synthesis techniques are our most powerful tools to synthesize short CNT segments such as carbon nanorings and carbon nanobelts. This Account highlights our 16-year campaign in the synthesis and application of carbon nanorings and carbon nanobelts. The first topic is the synthesis of carbon nanorings (cycloparaphenylenes) as substructures of CNTs. The second topic is the synthesis of armchair and zigzag carbon nanobelts, which consist solely of fully fused hexagonal rings and provide a continuous double-stranded cylindrical framework. The third topic is the synthesis of methylene-bridged cycloparaphenylene, an aromatic belt containing nonhexagonal rings, in which the cyclic paraphenylene chain is ladderized by methylene bridges. This nonalternant aromatic belt can be regarded as segments of nonconventional CNTs. During our extensive investigation, we found that the careful design of strainless macrocyclic precursors is crucial to the success of the synthesis of these curved p-conjugated nanorings and nanobelts. In the final section, some of the representative size-dependent properties of these nanorings/belts, including their HOMO-LUMO energies, strain energies, and photophysical properties, are summarized. In addition to basic properties, the utilization of these compounds as supramolecular hosts and organic materials is also briefly introduced. We hope this Account will inspire the development of new forms of nanocarbon molecules that would open doors to new fields and applications.

DOI： 10.1021/accountsmr.1c00105

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Arylcarbazoles have been widely used in materials science as important organic semiconductor molecules. To investigate the electronic and photophysical properties of arylcarbazole with different substitution patterns, facile and straightforward synthesis of arylcarbazole derivatives is sought after. Herein we report on photo-induced direct arylation reactions of carbazole. Treatment of carbazoles with aryldiazonium salts afforded the arylated carbazole. Although the reaction was not regioselective, C1 and C4-arylated carbazoles were obtained as the major isomers. When N-pyridylcarbazole was employed as the substrate with palladium catalyst, the reaction proceeded selectively at C1 position.

DOI： 10.1002/ajoc.202100191

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Strigolactones (SLs) are plant hormones that suppress shoot branching through perception by their receptor protein DWARF 14 (D14). The artificial regulation of SL signaling has been considered a potent agricultural technique because plant architecture is strongly related to crop yield. In this communication, we describe the development of a small-molecule D14 inhibitor that functions at sub-micromolar levels. This potent inhibitor may be a lead compound for a first-in-class plant growth regulator.

DOI： 10.1039/d0cc01989e

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

Cubane (C8H8), a cubic alkane, has long attracted attention owing to its unique 3D structure. In order to utilize the cubane scaffold widely in science and technology, a powerful method for synthesizing diverse cubane derivatives is required. Herein, we report the synthesis of mono-, di-, tri-, and tetra-arylated cubanes. Directedortho-metalation with lithium base/alkyl zinc and subsequent palladium-catalyzed arylation enabled C-H metalation and arylation of cubane. This reaction allows the late-stage and regioselective installation of a wide range of aryl groups, realizing the first programmable synthesis of diverse multiply arylated cubanes.

DOI： 10.1039/d0sc01909g

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The synthesis, structure, and properties of methylene-bridged [6]cycloparaphenylene ([6]CPP), a nonalternant aromatic belt, are described. This belt-shaped methylene-bridged [6]CPP, in which each phenylene unit is tethered to its neighbors by methylene bridges, was constructed through 6-fold intramolecular nickel-mediated aryl-aryl coupling of triflate-functionalized pillar[6]arene in 18% isolated yield. As compared to the analogous [6]CPP, the methylene bridges coplanarize neighboring paraphenylene units and enhance the degree of pi-conjugation, which results in a significant decrease in energy gap. Moreover, the incorporation of small molecules in the defined pocket of methylene-bridged [6]CPP makes it an attractive supramolecular architecture. Methylene-bridged [6]CPP is characterized by high internal strain energy reaching 110.2 kcal mol(-1), attributed to its restricted structure. This work not only exhibits an efficient strategy to construct a new family of aromatic belt, but also showcases their properties, which combine the merits of CPPs and pillararenes.

DOI： 10.1021/jacs.0c06007

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：BEILSTEIN-INSTITUT  

Hexa-peri-hexabenzocoronene (HBC) is known to be a poorly soluble polycyclic aromatic hydrocarbon for which direct functionalization methods have been very limited. Herein, the synthesis of hexaborylated HBC from unsubstituted HBC is described. Iridium-catalyzed six-fold C-H borylation of HBC was successfully achieved by screening solvents. The crystal structure of hexaborylated HBC was confirmed via X-ray crystallography. Optoelectronic properties of the thus-obtained hexaborylated HBC were analyzed with the support of density functional theory calculations. The spectra revealed a bathochromic shift of absorption bands compared with unsubstituted HBC under the effect of the sigma-donation of boryl groups.

DOI： 10.3762/bjoc.16.37

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The synthesis, structures, and properties of highly twisted, nonpianar aromatic macrocycles are described. These macrocycles with an approximately 90 degrees twist angle were synthesized by an effective synthetic approach through a quadruple Suzuki-Miyaura coupling of 4,5-bisarylphenanthrene, a novel axially chiral nonplanar building block. By varying the cross-coupling partner as the spacer, a family of twisted macrocycles was synthesized, allowing for a systematic study of the effect of the spacer on macrocycle shape and photophysical properties. For example, a unique macrocyclic aggregation-induced emission (AIE) emitter with double tetraphenylethylene units as the spacers was readily synthesized. Furthermore, attributed to its conformationally restricted twisted structure, a 3,6-disubstituted-1,8-naphthalimide-incorporated macrocycle showed remarkable solvatofluorochromism with high fluorescence quantum yields. The excellent conformational stability of these macrocycles further enabled complete enantiomeric resolution and characterization. The racemization barrier of macrocycle was determined experimentally and supported by DFT calculations.

DOI： 10.1021/jacs.9b13549

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PubMed

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.joc.9b02333

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The synthesis of sterically hindered phenanthrenes via acid-catalyzed bisannulation reaction is described. Treatment of 1,4-benzenediacetaldehyde with terminal aryl alkynes in the presence of B(C6F5)(3) provides 4,5-diarylphenanthrenes in good yields with excellent regioselectivity. The use of internal alkyne substrates enabled the synthesis of sterically hindered 3,4,5,6-tetrasubstituted phenanthrenes displaying augmented backbone helicity. Furthermore, 1,5-disubstituted, 1,8-disubstituted, 1,2,5,6-tetrasubstituted, and 1,2,7,8-tetrasubstituted phenanthrenes can be obtained through the reaction of alkynes with 1,3-benzenediacetaldehyde or 1,2-benzenediacetaldehyde disilyl acetal.

DOI： 10.1039/c9sc00334g

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PubMed

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.chempr.2019.03.013

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：SOC SYNTHETIC ORGANIC CHEM JPN  

Catalytic cleavage and reconnection of carbon-carbon bond is a powerful tool for organic synthesis. Recently, activation of inert carbon-carbon bonds has been rapidly developed. This review summarizes the progress of catalytic activation of carbon-carbon bonds in cyclopentanone derivatives.

DOI： 10.5059/yukigoseikyokaishi.75.864

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The synthesis and properties of various [n]cyclo-1,4-naphthylenes ([n]CNs, n = 8, 10, 12, and 16) are described. Initially, extended L-shaped units, which could be converted into quater- or quinquenaphthylenes were prepared. Nickel-or palladium-mediated couplings of these extended L-shaped units, followed by reductive aromatization of the coupling products afforded [8]-, [10]-, [12]-, and [16]CNs. The size-dependent photophysical properties of these CNs were confirmed by measuring their UV-vis absorption and fluorescence spectra. The theoretical studies supported substantial effects of the number of naphthalene rings on the structural and photophysical properties of these CNs. A kinetic study on the thermal conversion of the C-5-symmetric conformer of [10]CN into its most stable D-5d-symmetric conformer indicated that ring strain affects the rotation barrier of the naphthalene rings in [10]CN.

DOI： 10.1039/c6sc04048a

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WALTER DE GRUYTER GMBH  

Cycloparaphenylenes and analogues thereof are substances having excellent structural and electronic properties due to radial pi-conjugation modes and porous structures. Since they are partial structures of carbon nanotubes, they have also attracted attention as a template for carbon nanotube synthesis. In this chapter, we introduce a series of research on the synthesis of cycloparaphenylenes and their analogues.

DOI： 10.1515/psr-2016-0102

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Presentation type：Oral presentation (invited, special)  

Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (invited, special)  

Presentation type：Oral presentation (invited, special)  

Presentation type：Oral presentation (invited, special)  

Language：English   Presentation type：Oral presentation (general)  

Author：Myself