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Seiji Shinkai - One of the best experts on this subject based on the ideXlab platform.
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A Novel Sugar Sensing System Designed with a Cooperative Action of a Boronic-Acid-Appended Zinc Porphyrin and a 3-Pyridylboronic Acid Axial Ligand
Bulletin of the Chemical Society of Japan, 1997Co-Authors: Masayuki Takeuchi, Itaru Hamachi, Hideomi Kijima, Seiji ShinkaiAbstract:The cooperative action of two boronic Acids is indispensable to the selective binding of saccharides in aqueous solution and the binding process can be spectrophotometrically monitored by using porphyrins as a chromophoric probe. It is not so easy, however, to synthesize porphyrins that satisfy these prerequisites, i.e., porphyrins bearing two appropriately-arranged boronic Acid groups within a molecule. In this paper, we report that such a Diboronic-Acid-based porphyrin receptor can be easily designed by utilizing the self-assembling nature of a Zn(II) porphyrin and an axial ligand: That is, a mixture of boronic-Acid-appended Zn(II) porphyrin (1-Zn) and 3-pyridylboronic Acid (2) self-organizes to create a novel Diboronic Acid system for saccharide (S) recognition. Thus, the 1-Zn·2·S ternary complexes give the CD spectral pattern inherent to saccharide absolute configuration. The present study is a new example for sugar sensing using a boronic Acid-porphyrin self-assembly system.
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Chiroselective transcription of the sugar structure to Δ- orΛ-[CoIII(bpy)3]3+ usinga boronic Acid–sugar template interaction
Chemical Communications, 1997Co-Authors: Toshihisa Mizuno, Kazuaki Nakashima, Masayuki Takeuchi, Itaru Hamachi, Seiji ShinkaiAbstract:In order to apply boronic Acid–saccharide interactions to the chiroselective synthesis of Δ- and Λ-[Co III (bpy) 3 ] 3+ a saccharide-binding ligand, 2,2′-bipyridine-4,4′-Diboronic Acid (bpyba) is newly synthesized; the enantiomeric excess under the optimum reaction conditions reached 79% ee!
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Molecular design of sugar recognition systems by sugar-Diboronic Acid macrocyclization
Pure and Applied Chemistry, 1996Co-Authors: K. R. A. S. Sandanayake, Tony D. James, Seiji ShinkaiAbstract:Boronic Acid is known to complex with saccharides in basic aqueous media with an inherent selectivity order. Cooprative binding of Diboronic Acid which creates a sugar Diboronic Acid macrocycle has been utilized in design of molecular receptors with a diffrent selectivity order. Cooparative binding together with photoinduced electron transfer mechanism has been utilized in design of sensitive and selective saccharide sensors.
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Fluorescent saccharide receptors: A sweet solution to the design, assembly and evaluation of boronic Acid derived PET sensors
Chemical Communications, 1996Co-Authors: Tony D. James, Patrick Linnane, Seiji ShinkaiAbstract:This review article briefly introduces the applications of photoinduced electron transfer receptors (PET) and then progresses from the design, assembly and evaluation of a simple monofunctional monoboronic Acid through to a variety of bifunctional Diboronic Acid saccharide receptors.
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Synthesis of Helical Polymers by Polycondensation of Diboronic Acid and Chiral Tetrols.
Chemistry Letters, 1995Co-Authors: Masafumi Mikami, Seiji ShinkaiAbstract:Polymers containing sugar units in the main chain were synthesized by polycondensation of Diboronic Acid and C2-symmetrical chiral tetrols. Spectroscopic studies and theoretical calculations established that they possess a DNA-like helical structure.
Tony D. James - One of the best experts on this subject based on the ideXlab platform.
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Selective Saccharide Recognition Using Modular Diboronic Acid Fluorescent Sensors
European Journal of Organic Chemistry, 2012Co-Authors: Zhitao Xing, Tony D. James, Hui-chen Wang, Yixiang Cheng, Chengjian Zhu, Jianzhang ZhaoAbstract:Modular Diboronic Acid receptors R-1 and S-1 were synthesized and found to be selective fluorescent chemosensors for saccharides. The fluorescence intensity of R-1 and S-1 increased on addition of saccharides due to the formation of intramolecular 1:1 cyclic complexes. In general, R-1 has higher binding constants and produces a higher fluorescent response with saccharides than S-1. The fluorescence intensity of receptors R-1 and S-1 increased on addition of saccharides due to the formation of intramolecular 1:1 cyclic complexes. In general, R-1 has higher binding constants and produces a higher fluorescent response with saccharides than S-1.
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Modular fluorescence sensors for saccharides
Journal of the Chemical Society Perkin Transactions 1, 2002Co-Authors: Susumu Arimori, Michael L. Bell, Karine A. Frimat, Tony D. JamesAbstract:Modular photoinduced electron transfer (PET) sensors bearing two phenylboronic Acid groups, a pyrene group and alkylene linkers, from trimethylene to octamethylene, have been prepared and evaluated. The Diboronic Acid systems with tetramethylene 3444 pentamethylene 3555 and hexamethylene 3666 linkers display the greatest enhancement in binding relative to monoboronic Acid 4 with D-glucose. The Diboronic Acid system with the hexamethylene 3666 linker is particularly D-glucose selective and sensitive. Whilst the Diboronic Acid systems with the longer heptamethylene 3777 and octamethylene 3888 linkers display the greatest enhancement in binding relative to monoboronic Acid 4 with D-galactose. All saccharide titrations were performed in methanolic aqueous solution.
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A d-glucose selective fluorescent assay
Tetrahedron Letters, 2002Co-Authors: Susumu Arimori, Christopher J. Ward, Tony D. JamesAbstract:A d-glucose selective competition assay has been devised using Alizarin Red S and Diboronic Acid 2 in buffered aqueous solution.
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Molecular design of sugar recognition systems by sugar-Diboronic Acid macrocyclization
Pure and Applied Chemistry, 1996Co-Authors: K. R. A. S. Sandanayake, Tony D. James, Seiji ShinkaiAbstract:Boronic Acid is known to complex with saccharides in basic aqueous media with an inherent selectivity order. Cooprative binding of Diboronic Acid which creates a sugar Diboronic Acid macrocycle has been utilized in design of molecular receptors with a diffrent selectivity order. Cooparative binding together with photoinduced electron transfer mechanism has been utilized in design of sensitive and selective saccharide sensors.
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Fluorescent saccharide receptors: A sweet solution to the design, assembly and evaluation of boronic Acid derived PET sensors
Chemical Communications, 1996Co-Authors: Tony D. James, Patrick Linnane, Seiji ShinkaiAbstract:This review article briefly introduces the applications of photoinduced electron transfer receptors (PET) and then progresses from the design, assembly and evaluation of a simple monofunctional monoboronic Acid through to a variety of bifunctional Diboronic Acid saccharide receptors.
Richard G. Weiss - One of the best experts on this subject based on the ideXlab platform.
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Influence of length and structure of aryl boronic Acid crosslinkers on organogels with partially hydrolyzed poly(vinyl acetate)
Colloid and Polymer Science, 2018Co-Authors: Teresa T. Duncan, Richard G. WeissAbstract:Organogels composed of 40% hydrolyzed poly(vinyl acetate) (40PVAc) and three arylboronic Acids have been formed and characterized in several liquids to gain insights into the role of crosslinker length and structure on the properties of the gels. Data from ^1H NMR, steady-state and time-resolved fluorescence, and rheology have been employed to correlate the degrees of crosslinking and the bulk physical properties of the gels. Benzene-1,4-Diboronic Acid (1,4-BDBA) and 4,4′-biphenylDiboronic Acid (bPDBA) formed gels with 40PVAc that were stable for longer periods than those with benzene-1,3-Diboronic Acid. Surprisingly, the steady-state and time-resolved fluorescence properties of 1,4-BDBA or bPDBA were affected very little in solution upon addition of two model diols (1,3-propanediol and 1,2-ethanediol) or even 40PVAc. Furthermore, 40PVAc appeared to form crosslinks more efficiently, resulting in stiffer gels, with bPDBA than with 1,4-BDBA. We attribute these trends to the greater length, flexibility, and linearity of bPBPA. Overall, the results reported here demonstrate that minor structural changes in the crosslinker can alter significantly many of the bulk properties of two-component organogel networks. They also provide a clear ‘blueprint’ for making gels with specific desired properties for a range of applications that require virtually water-free systems.
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Soft, Peelable Organogels from Partially Hydrolyzed Poly(vinyl acetate) and Benzene-1,4-Diboronic Acid: Applications to Clean Works of Art
ACS applied materials & interfaces, 2017Co-Authors: Teresa T. Duncan, Barbara H. Berrie, Richard G. WeissAbstract:We have developed soft, peelable organogels from 40% hydrolyzed poly(vinyl acetate) (40PVAc) and benzene-1,4-Diboronic Acid (BDBA). The organic liquids gelated include dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, 2-ethoxyethanol, and methanol. The rheology of these soft materials can be tuned by altering the concentration of the polymer and/or crosslinker. Insights into the mechanisms leading to gelation were obtained from 1H NMR experiments, fluorescence measurements, and studies comparing properties of materials made from BDBA and phenylboronic Acid, a molecule incapable of forming covalent crosslinks between the polymer chains. These organogels can be easily peeled off a surface, leaving no residue detectable by UV–vis spectroscopy. They are demonstrated to be effective at softening and removing deteriorated coatings from water-sensitive works of art and delicate surfaces. They have the needed characteristics to clean topographically complex surfaces: good contact with the surface, easy remo...
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Soft, Peelable Organogels from Partially Hydrolyzed Poly(vinyl acetate) and Benzene-1,4-Diboronic Acid: Applications to Clean Works of Art
2017Co-Authors: Teresa T. Duncan, Barbara H. Berrie, Richard G. WeissAbstract:We have developed soft, peelable organogels from 40% hydrolyzed poly(vinyl acetate) (40PVAc) and benzene-1,4-Diboronic Acid (BDBA). The organic liquids gelated include dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, 2-ethoxyethanol, and methanol. The rheology of these soft materials can be tuned by altering the concentration of the polymer and/or crosslinker. Insights into the mechanisms leading to gelation were obtained from 1H NMR experiments, fluorescence measurements, and studies comparing properties of materials made from BDBA and phenylboronic Acid, a molecule incapable of forming covalent crosslinks between the polymer chains. These organogels can be easily peeled off a surface, leaving no residue detectable by UV–vis spectroscopy. They are demonstrated to be effective at softening and removing deteriorated coatings from water-sensitive works of art and delicate surfaces. They have the needed characteristics to clean topographically complex surfaces: good contact with the surface, easy removal, and little to no residue after removal. A 2-ethoxyethanol organogel was used to remove oxidized varnish from a 16th century reliquary decorated with painted gold leaf, and an ethanol gel was used to remove solvent-resistant coatings from 16th and 18th century oil paintings
Martin A Iglesiasarteaga - One of the best experts on this subject based on the ideXlab platform.
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synthesis of symmetrical and hybrid dimeric steroids by double suzuki miyaura cross coupling of 4 bromo 3 oxo steroids and benzene 1 4 Diboronic Acid
Synthesis, 2019Co-Authors: Martha C Mayorquintorres, Gerardo I Santiagosampedro, Marcos Floresalamo, Martin A IglesiasarteagaAbstract:Two symmetrical dimers and one hybrid dimer in which the steroid cores are connected by a 1,4-phenylene moiety were obtained by double Suzuki–Miyaura cross coupling of benzene-1,4-Diboronic Acid with 4-bromo-4-en-3-oxosteroids derived from cholesterol and diosgenin. Detailed NMR characterization of the obtained dimers is described.
Martín A. Iglesias-arteaga - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Symmetrical and Hybrid Dimeric Steroids by Double Suzuki–Miyaura Cross Coupling of 4-Bromo-3-oxo Steroids and Benzene-1,4-Diboronic Acid
Synthesis, 2019Co-Authors: Martha C. Mayorquín-torres, Gerardo I. Santiago-sampedro, Marcos Flores-alamo, Martín A. Iglesias-arteagaAbstract:Two symmetrical dimers and one hybrid dimer in which the steroid cores are connected by a 1,4-phenylene moiety were obtained by double Suzuki–Miyaura cross coupling of benzene-1,4-Diboronic Acid with 4-bromo-4-en-3-oxosteroids derived from cholesterol and diosgenin. Detailed NMR characterization of the obtained dimers is described.