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  1. Article: 2-O-Methylated β-Cyclodextrin as an Effective Building Block to Construct Supramolecular Assemblies with Various Morphologies and Molecular Arrangements

    Kalaw, Justine M. / Shigemitsu, Hajime / Kida, Toshiyuki

    Langmuir. 2022 June 28, v. 38, no. 27

    2022  

    Abstract: The preparation of supramolecular cyclodextrin (CD) assemblies and control of their assembly mode through guest inclusion in CD cavities have been actively studied. Contrarily, there are limited reports on the control of the assembly mode of guest-free ... ...

    Abstract The preparation of supramolecular cyclodextrin (CD) assemblies and control of their assembly mode through guest inclusion in CD cavities have been actively studied. Contrarily, there are limited reports on the control of the assembly mode of guest-free CD molecules by external stimuli. Herein, we report the use of 2-O-methylated β-cyclodextrin (2-Me-β-CD) as an effective building block in fabricating supramolecular assemblies with diverse morphologies and molecular arrangements through assembly mode control by various stimuli, such as temperature and solvent. When methanol and diethyl carbonate were used as good and poor solvents, respectively, 2-Me-β-CD formed an amorphous assembly through solvent evaporation on a polyethylene terephthalate (PET) substrate. Increasing the drying temperature and using crystalline substrates, such as highly oriented pyrolytic graphite (HOPG) and sapphire, changed the assembly mode of 2-Me-β-CD to a head-to-tail channel assembly. However, when a 2-Me-β-CD/1-propanol solution was mixed with linear alkanes as a poor solvent, 2-Me-β-CD with head-to-head channel assembly was formed as a precipitate. Additionally, when the corresponding cyclic alkane was used as an alternative poor solvent, an organogel composed of 2-Me-β-CD with head-to-head channel assemblies was obtained. The organogel obtained became a precipitate composed of 2-Me-β-CD with cage-type assembly upon heating at 50 °C. Among the supramolecular assemblies fabricated in this study, the head-to-tail channel assembly is a rare molecular assembly of β-CD and its derivatives. It possesses a modified columnar cavity that has potential applications in molecular recognition and sensing.
    Keywords alkanes ; carbonates ; evaporation ; graphene ; methanol ; organogels ; polyethylene terephthalates ; solvents
    Language English
    Dates of publication 2022-0628
    Size p. 8407-8415.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/acs.langmuir.2c00980
    Database NAL-Catalogue (AGRICOLA)

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  2. Article ; Online: 2-

    Kalaw, Justine M / Shigemitsu, Hajime / Kida, Toshiyuki

    Langmuir : the ACS journal of surfaces and colloids

    2022  Volume 38, Issue 27, Page(s) 8407–8415

    Abstract: The preparation of supramolecular cyclodextrin (CD) assemblies and control of their assembly mode through guest inclusion in CD cavities have been actively studied. Contrarily, there are limited reports on the control of the assembly mode of guest-free ... ...

    Abstract The preparation of supramolecular cyclodextrin (CD) assemblies and control of their assembly mode through guest inclusion in CD cavities have been actively studied. Contrarily, there are limited reports on the control of the assembly mode of guest-free CD molecules by external stimuli. Herein, we report the use of 2-
    Language English
    Publishing date 2022-06-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/acs.langmuir.2c00980
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Preparation and temperature-controlled morphology of helical microrods composed of supramolecular α-cyclodextrin assemblies.

    Kida, Toshiyuki / Teragaki, Ayumi / Ishida, Haruya / Sonoda, Sayaka / Miyasaka, Momoka / Shigemitsu, Hajime

    RSC advances

    2023  Volume 13, Issue 49, Page(s) 34366–34370

    Abstract: Significant efforts have been devoted so far to artificially fabricate supramolecular helical nano- and microstructures through the regulated assembly of biological and synthetic building blocks. However, the preparation of supramolecular helical ... ...

    Abstract Significant efforts have been devoted so far to artificially fabricate supramolecular helical nano- and microstructures through the regulated assembly of biological and synthetic building blocks. However, the preparation of supramolecular helical structures with a regulated morphology remains challenging. Here, helical microrods composed of supramolecular α-cyclodextrin (α-CD) assemblies were fabricated by allowing an α-CD/1,1,1,3,3,3-hexafluoro-2-propanol (HFIP)/2-pentanol mixture to stand at 30-60 °C under high humidity conditions. The morphology could be controlled by temperature to produce helical microrods with a regulated pitch and length. These helical rods can be applied as optical devices, chiral separation devices and asymmetric catalysts.
    Language English
    Publishing date 2023-11-23
    Publishing country England
    Document type Journal Article
    ISSN 2046-2069
    ISSN (online) 2046-2069
    DOI 10.1039/d3ra07537k
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Supramolecular nanosheet formation-induced photosensitisation mechanism change of Rose Bengal dye in aqueous media.

    Bunno, Asuka / Shigemitsu, Hajime / Yoshikawa, Aya / Osakada, Yasuko / Fujitsuka, Mamoru / Ishiwari, Fumitaka / Saeki, Akinori / Ohkubo, Kei / Mori, Tadashi / Kida, Toshiyuki

    Chemical communications (Cambridge, England)

    2024  Volume 60, Issue 7, Page(s) 889–892

    Abstract: Development of two-dimensional materials and exploration of their functionalities are significant challenges due to their potential. In this study, we successfully fabricated a supramolecular nanosheet composed of amphiphilic Rose Bengal dyes in an ... ...

    Abstract Development of two-dimensional materials and exploration of their functionalities are significant challenges due to their potential. In this study, we successfully fabricated a supramolecular nanosheet composed of amphiphilic Rose Bengal dyes in an aqueous medium. Furthermore, we elucidated a distinct change in the photosensitisation mechanism induced by nanosheet formation.
    Language English
    Publishing date 2024-01-18
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472881-3
    ISSN 1364-548X ; 1359-7345 ; 0009-241X
    ISSN (online) 1364-548X
    ISSN 1359-7345 ; 0009-241X
    DOI 10.1039/d3cc05731c
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Visible Light-Induced Regio- and Enantiodifferentiating [2 + 2] Photocycloaddition of 1,4-Naphthoquinones Mediated by Oppositely Coordinating 1,3,2-Oxazaborolidine Chiral Lewis Acid.

    Shimizu, Nao / Shigemitsu, Hajime / Kida, Toshiyuki / Bach, Thorsten / Mori, Tadashi

    The Journal of organic chemistry

    2022  Volume 87, Issue 12, Page(s) 8071–8083

    Abstract: A range of asymmetric photochemical transformations using visible light have recently become considerably attractive. Among the various approaches, chiral Lewis acid association to enones for [2 + 2] ... ...

    Abstract A range of asymmetric photochemical transformations using visible light have recently become considerably attractive. Among the various approaches, chiral Lewis acid association to enones for [2 + 2] and
    MeSH term(s) Lewis Acids/chemistry ; Light ; Naphthoquinones ; Stereoisomerism
    Chemical Substances Lewis Acids ; Naphthoquinones
    Language English
    Publishing date 2022-06-01
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.2c00730
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Visible Light-Induced Regio- and Enantiodifferentiating [2 + 2] Photocycloaddition of 1,4-Naphthoquinones Mediated by Oppositely Coordinating 1,3,2-Oxazaborolidine Chiral Lewis Acid

    Shimizu, Nao / Shigemitsu, Hajime / Kida, Toshiyuki / Bach, Thorsten / Mori, Tadashi

    Journal of organic chemistry. 2022 June 02, v. 87, no. 12

    2022  

    Abstract: A range of asymmetric photochemical transformations using visible light have recently become considerably attractive. Among the various approaches, chiral Lewis acid association to enones for [2 + 2] and ortho photocycloadditions and oxadi-π-methane ... ...

    Abstract A range of asymmetric photochemical transformations using visible light have recently become considerably attractive. Among the various approaches, chiral Lewis acid association to enones for [2 + 2] and ortho photocycloadditions and oxadi-π-methane rearrangements have shown to be very promising. Naturally, chiral Lewis acid coordination protects one of the prochiral faces of the C═C double bond, which enables an effective enantiodifferentiation in the following bond-forming process(es). Here, we studied regio- and enantiodifferentiating [2 + 2] photocycloaddition reactions of naphthoquinone derivatives mediated by chiral oxazaborolidines. A stereochemical control was quite challenging for the 2-ene-1,4-dione substrate, as a double coordination of Lewis acid essentially cancels out the face selectivity, and a mono-coordination to each carbonyl group leads to an opposite stereochemical outcome. Furthermore, a stepwise coordination in the ground state of Lewis acid in a 1:1 fashion was practically inaccessible. We found that the excited-state decomplexation is a key to accomplish high regio- and enantioselectivities in the photocycloaddition of an ene-dione.
    Keywords Lewis acids ; face ; light ; naphthoquinones ; organic chemistry ; photochemistry ; stereochemistry
    Language English
    Dates of publication 2022-0602
    Size p. 8071-8083.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 123490-0
    ISSN 1520-6904 ; 0022-3263
    ISSN (online) 1520-6904
    ISSN 0022-3263
    DOI 10.1021/acs.joc.2c00730
    Database NAL-Catalogue (AGRICOLA)

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  7. Article ; Online: Highly Regulated Supramolecular Assembly of 2-

    Kalaw, Justine M / Kitagawa, Mizuki / Shigemitsu, Hajime / Kida, Toshiyuki

    Langmuir : the ACS journal of surfaces and colloids

    2021  Volume 38, Issue 17, Page(s) 5149–5155

    Abstract: Precisely controlling self-assembled molecules to fabricate highly ordered nano/microstructures is a challenging task. Here, a simple precipitation technique with common solvents forms supramolecular microstructures with highly regulated molecular ... ...

    Abstract Precisely controlling self-assembled molecules to fabricate highly ordered nano/microstructures is a challenging task. Here, a simple precipitation technique with common solvents forms supramolecular microstructures with highly regulated molecular arrangements from a methylated derivative of α-cyclodextrin at the 2-
    Language English
    Publishing date 2021-10-15
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/acs.langmuir.1c02238
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Porphyrin covalent organic nanodisks synthesized using acid-assisted exfoliation for improved bactericidal efficacy.

    Li, Xinxi / Shigemitsu, Hajime / Goto, Tomoyo / Kida, Toshiyuki / Sekino, Tohru / Fujitsuka, Mamoru / Osakada, Yasuko

    Nanoscale advances

    2022  Volume 4, Issue 14, Page(s) 2992–2995

    Abstract: Porphyrin covalent organic nanodisks (CONs) were synthesized by exfoliating covalent organic frameworks (COFs) in acidic aqueous solutions at pH 4. The synthesized CONs showed remarkable bactericidal activity ... ...

    Abstract Porphyrin covalent organic nanodisks (CONs) were synthesized by exfoliating covalent organic frameworks (COFs) in acidic aqueous solutions at pH 4. The synthesized CONs showed remarkable bactericidal activity against
    Language English
    Publishing date 2022-06-16
    Publishing country England
    Document type Journal Article
    ISSN 2516-0230
    ISSN (online) 2516-0230
    DOI 10.1039/d2na00318j
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: A cyanine dye based supramolecular photosensitizer enabling visible-light-driven organic reaction in water

    Shigemitsu, Hajime / Tamemoto, Tomoe / Ohkubo, Kei / Mori, Tadashi / Osakada, Yasuko / Fujitsuka, Mamoru / Kida, Toshiyuki

    Chemical communications. 2021 Oct. 26, v. 57, no. 85

    2021  

    Abstract: We report the aggregation-induced photosensitizing activity of a cyanine dye in water and the mechanism. In addition, using the supramolecular assembly, visible-light-driven photooxidation of hydrophobic aromatic compounds in water was successfully ... ...

    Abstract We report the aggregation-induced photosensitizing activity of a cyanine dye in water and the mechanism. In addition, using the supramolecular assembly, visible-light-driven photooxidation of hydrophobic aromatic compounds in water was successfully performed.
    Keywords dyes ; hydrophobicity ; photooxidation ; photosensitizing agents
    Language English
    Dates of publication 2021-1026
    Size p. 11217-11220.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 1472881-3
    ISSN 1364-548X ; 1359-7345 ; 0009-241X
    ISSN (online) 1364-548X
    ISSN 1359-7345 ; 0009-241X
    DOI 10.1039/d1cc04685c
    Database NAL-Catalogue (AGRICOLA)

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  10. Article: Highly Regulated Supramolecular Assembly of 2-O-Methylated α-Cyclodextrin to Construct Vertically Oriented Microrods on Graphite

    Kalaw, Justine M. / Kitagawa, Mizuki / Shigemitsu, Hajime / Kida, Toshiyuki

    Langmuir. 2021 Oct. 15, v. 38, no. 17

    2021  

    Abstract: Precisely controlling self-assembled molecules to fabricate highly ordered nano/microstructures is a challenging task. Here, a simple precipitation technique with common solvents forms supramolecular microstructures with highly regulated molecular ... ...

    Abstract Precisely controlling self-assembled molecules to fabricate highly ordered nano/microstructures is a challenging task. Here, a simple precipitation technique with common solvents forms supramolecular microstructures with highly regulated molecular arrangements from a methylated derivative of α-cyclodextrin at the 2-O position (2-Me-α-CD). The formation of a head-to-tail channel assembly of 2-Me-α-CD through host–guest complexation with a solvent molecule such as benzene or cyclohexane yields well-defined hexagonal microrods. Specifically, the self-assembly of 2-Me-α-CD forms vertically aligned hexagonal microrods on a highly ordered pyrolytic graphite (HOPG) surface via epitaxial growth. This work should provide insight into the design of supramolecular building blocks for controlled self-assembly.
    Keywords benzene ; cyclohexanes ; graphene ; methylation ; solvents
    Language English
    Dates of publication 2021-1015
    Size p. 5149-5155.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 2005937-1
    ISSN 1520-5827 ; 0743-7463
    ISSN (online) 1520-5827
    ISSN 0743-7463
    DOI 10.1021/acs.langmuir.1c02238
    Database NAL-Catalogue (AGRICOLA)

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