Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

<jats:title>Abstract</jats:title><jats:p>Two kinds of planarized phenyldithienylboranes, which contain (CH<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>C‐ or CH<jats:sub>2</jats:sub>‐bridging moieties, were synthesized. The difference of the bridging moieties affects their packing structures and photophysical properties. In particular, the (CH<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub>C‐bridged derivative exhibits a large Stokes shift, unusual for such planarized compounds, that results from a large structural relaxation in the excited state. A series of π‐extended derivatives was synthesized, among which a<jats:italic>p</jats:italic>‐(diphenylamino)phenyl‐substituted derivative shows large solvatochromism in the fluorescence spectra, while maintaining high quantum yields even in polar solvents. The Lewis acidity of the phenyldithienylborane derivatives was also assessed by titration with pyridine. The Lewis acidity of the boron center is affected not only by the difference in the steric bulk of the bridging moieties, but also by the electronic effect of the substituents introduced at remote positions relative to the boron atom. These results demonstrate the characteristic features of planarized phenyldithienylboranes as building blocks for boron‐based π‐electron materials.</jats:p>

DOI： 10.1002/chem.202200728

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CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Angewandte Chemie - International Edition  

Embedding two boron atoms into a polycyclic aromatic hydrocarbon (PAH) leads to the formation of a neutral analogue that is isoelectronic to the corresponding dicationic PAH skeleton, which can significantly alter its electronic structure. Based on this concept, we explore herein the identification of near-infrared (NIR)-emissive PAHs with the aid of an in silico screening method. Using perylene as the PAH scaffold, we embedded two boron atoms and fused two thiophene rings to it. Based on this design concept, all possible structures (ca. 2500 entities) were generated using a comprehensive structure generator. Time-dependent DFT calculations were conducted on all these structures, and promising candidates were extracted based on the vertical excitation energy, transition dipole moment, and atomization energy per bond. One of the extracted dithieno-diboraperylene candidates was synthesized and indeed exhibited emission at 724 nm with a quantum yield of 0.40 in toluene, demonstrating the validity of this screening method. This modification was further applied to other PAHs, and a series of thienobora-modified PAHs was synthesized.

DOI： 10.1002/anie.202403829

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers in Chemistry  

We studied the photophysical and electroluminescent (EL) characteristics of a series of azaborine derivatives having a pair of boron and nitrogen aimed at the multi-resonance (MR) effect. The computational study with the STEOM-DLPNO-CCSD method clarified that the combination of a BN ring-fusion and a terminal carbazole enhanced the MR effect and spin-orbit coupling matrix element (SOCME), simultaneously. Also, we clarified that the second triplet excited state (T2) plays an important role in efficient MR-based thermally activated delayed fluorescence (TADF). Furthermore, we obtained a blue–violet OLED with an external EL quantum efficiency (EQE) of 9.1%, implying the presence of a pronounced nonradiative decay path from the lowest triplet excited state (T1).

DOI： 10.3389/fchem.2022.990918

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

<jats:title>Abstract</jats:title><jats:p>Catalyst‐free 1,2‐carboboration of ynamides is presented. Readily available aryldichloroboranes react with alkyl‐ or aryl‐substituted ynamides in high yields with complete regio‐ and stereoselectivity to valuable β‐boryl‐β‐alkyl/aryl α‐aryl substituted enamides which belong to the class of trisubstituted alkenylboronates. The 1,2‐carboboration reaction is experimentally easy to conduct, shows high functional group tolerance and broad substrate scope. Gram‐scale reactions and diverse synthetic transformations convincingly demonstrate the synthetic potential of this method. The reaction can also be used to access 1‐boraphenalenes, a class of boron‐doped polycyclic aromatic hydrocarbons.</jats:p>

DOI： 10.1002/anie.202107647

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CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

<jats:title>Abstract</jats:title><jats:p>Electron‐deficient heteroacenes that contain two tricoordinate boron atoms in their acene skeletons and planarized phenyl ether moieties at their periphery were synthesized via the borylation of silicon‐bridged precursors. X‐ray crystallographic analysis revealed quinoidal structures, which give rise to two‐step reversible redox processes for both the reduction and oxidation. These compounds exhibit intense absorption and sharp fluorescence bands with vibronic structures in the near‐infrared (NIR) region. These properties originate from the push–pull effect along the long axis of the molecule derived from the electron‐donating ether moieties and the electron‐accepting boron moieties. Of particular note is the NIR emission of the thienothiophene‐centered heteroacene, which has a maximum at 952 nm with a narrow band width of 309 cm<jats:sup>−1</jats:sup> in cyclohexane. A Franck–Condon analysis revealed the crucial role of the sterically less‐hindered thienothiophene spacer in achieving this sharp emission band.</jats:p>

DOI： 10.1002/anie.202106642

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CiNii Research

Event date： 2024.8

Language：English   Presentation type：Poster presentation  

Venue：Toronto, Canada   Country：Canada  

Event date： 2024.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：日本大学   Country：Japan