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2022-2

凝集誘起発光(AIE)の原理と未来<展望>9月号特集「凝集誘起〇〇 集めてもらえるステキな特典」(9月1日発行)
小西 玄一
高分子(高分子学会会報), 71, 463–465 (2022)
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# by konishi_lab | 2022-11-02 15:42 | 2022(5)

2022-1

Rhodium-Catalyzed Intermolecular Cycloaromatization Route to Cycloparaphenylenes that Exhibit Aggregation-Induced Emission
L.-H. Wang,Y. Nagashima,M. Abekura,H. Uekusa, G. Konishi, K. Tanaka
Chem. Eur. J., 28, e202200064 (2022)
DOI: 10.1002/chem.202200064
Link
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Abstract: We have developed a high-yielding new route to substituted cycloparaphenylenes via reductive aromatization of a diyne bearing two cyclohexadiene units giving a cyclophenylene-ethynylene (CPE) followed by the cationic rhodium(I)/dppe complex-catalyzed intermolecular [2+2+2] cycloaddition (c ycloaromatization) of the CPE with monoynes . The thus obtained products, substituted [8]cycloparaphenylene-triphenylenes ([8]CPPTs), exhibited definite aggregation-induced emission (AIE) . This molecule is noteworthy as a novel AIE-active cycloarylene that does not have well-known AIE luminogens, such as tetraphenylethene and 1,2,4,5-tetraphenylbenzene skeletons. The single-crystal X-ray diffraction analyses of the AIE-active [8]CPPTs revealed their highly ordered packing structures in which the rotation of the triphenylene moieties is restricted.


# by konishi_lab | 2022-09-02 18:09 | 2022(5)

南1号館に移動しました(2021年4月から)

小西研は、東工大大岡山キャンパスの南1号館に移動しております。

HPのURLも物質理工学院のドメインに変更されています。

以前のHPからは、自動転送されます。

小西研HP
http://www.konishi-cap.mac.titech.ac.jp/index.html


南1号館に移動しました(2021年4月から)_b0202136_21000555.jpg

# by konishi_lab | 2022-05-29 21:53 | News

2020-3

Birefringence and photoluminescence properties of diphenylacetylene-based liquid crystal dimers
Y. Arakawa, S. Sasaki, K. Igawa, M. Tokita, G. Konishi, H. Tsuji
New. J. Chem., 44, 17531-17541 (2020)
DOI: 10.1039/D0NJ04426A
Link
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Abstract: We herein report phase transitions, mesomorphism, birefringence behavior and photoluminescence properties of symmetric liquid crystal (LC) dimers based on diphenylacetylene or tolane. A homologous series of 4-methoxy tolanes linked with oligomethylene spacers consisting of carbon numbers (m) of 5–12 via ether linkages (1OTOmOTO1) were developed. The 1OTOmOTO1 series exhibited only a nematic phase, in contrast with the previously reported homologues with long terminal alkoxy chains, which exhibit layered smectic phases. We revealed that even the longest even-numbered 1OTO12OTO1 exhibits higher birefringence (Δn) than the shortest odd-numbered 1OTO5OTO1 at similar shifted temperatures. This fact suggests that the parity effect in the spacer that enhances Δn in an even-m surpasses the dilution effect that decreases Δn in large m for LC dimers. In addition, the photophysical measurements found aggregation-induced emission of the dimer concomitant with the emergence of an abnormally structured fluorescence band, which perhaps arises from a unique excited state enabled by aggregation. Single-crystal structural analysis revealed that diphenylacetylene moieties in neighboring molecules have face-to-edge orthogonal packing with one another, supporting the strong face-to-edge preferences of diphenylacetylene moiety and its enhanced fluorescence in aggregated states.


# by konishi_lab | 2022-05-29 21:40 | 2020 (3)

2020-2

Open Access
Review 
Top 1% Highly Cited Article (Web of Science)
Principles of Aggregation-Induced Emission: Design of Deactivation Pathways for Advanced AIEgens and Applications
S. Suzuk, S. Sasaki, A. S. Sairi, R. Iwai, B. Z. Tang, G. Konishi*
Angew. Chem. Int. Ed., 59, 9856–9867 (2020)
DOI: 10.1002/anie.202000940
Link
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Abstract: Twenty years ago, the concept of aggregation‐induced emission (AIE) was proposed, and this unique luminescent property has attracted scientific interest ever since. However, AIE denominates only the phenomenon, while the details of its underlying guiding principles remain to be elucidated. This mini review discusses the basic principles of AIE based on our previous mechanistic study on the photophysical behavior of 9,10‐bis( N , N ‐dialkylamino)anthracene ( BDAA ) and the corresponding mechanistic analysis by quantum chemical calculations. BDAA comprises of an anthracene core and small electron donors, which allows discussing the quantum‐chemical aspects of AIE. The key factor for AIE is the control over the non‐radiative decay (deactivation) pathway, which can be visualized by considering the conical intersection (CI) on a potential energy surface. Controlling the conical intersection (CI) on the potential energy surface enables the separate formation of fluorescent (CI:high) and non‐fluorescent (CI:low) molecules. The novelty and originality of AIE in the field of photochemistry lies in the creation of functionality by design and in the active control over deactivation pathways. Moreover, we provide a new design strategy for AIE luminogens (AIEgens) and discuss selected examples.


# by konishi_lab | 2020-04-23 20:05 | 2020 (3)