Self‐Assembled Receptors that Stereoselectively Recognize a Saccharide

Ishi‐i, Tsutomu; Mateos‐Timoneda, Miguel A.; Timmerman, Peter; Crego‐Calama, Mercedes; Reinhoudt, David N.; Shinkai, Seiji

doi:10.1002/ange.200350956

Cited by 67 publications

(70 citation statements)

References 63 publications

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“…Thus, a supramolecular self-assembled system is regarded as one of the most suitable media for chiral amplification, in which chiral information of the chiral sergeant component is transferred to the soldier-based aggregate via the noncovalent interactions and amplified to control the entire supramolecular chirality. The chiral aggregates produced by chiral amplification would provide an attractive medium for asymmetric reactions [15] and chiral recognition, [16] as well as applications as nanoscale functional materials with piezoelectric, pyroelectric, and ferroelectric properties, [17] although the low stability of the noncovalent architecture should be overcome by using chemical modification such as covalent fixation. Recently, Meijer et al reported fixation of a chiral structure created in a columnar-type helical aggregate by a chiral-amplification method.…”

Section: Introductionmentioning

confidence: 99%

An Enantiomeric Nanoscale Architecture Obtained from a Pseudoenantiomeric Aggregate: Covalent Fixation of Helical Chirality Formed in Self‐Assembled Discotic Triazine Triamides by Chiral Amplification

Ishi‐i

Kuwahara

Takata

et al. 2006

Chemistry A European J

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Covalent fixation of a chiral helical structure which is created in a self-assembling system by a chiral-amplification method based on the sergeants/soldiers principle is reported. Disk-shaped triazine triamides self-assembled to form columnar-type helical aggregates through pi-stacking interactions among the central triphenyltriazine moieties, hydrogen-bonding interactions among the amide groups, and van der Waals interactions among the alkyl groups in nonpolar solvents such as hexane, octane, toluene, and p-xylene. When the achiral triazine triamide soldier component is mixed with a tiny amount of the chiral triazine triamide sergeant component, control of the intrinsic supramolecular helicity of the self-assembled soldier component by the sergeant component leads to chiral amplification and formation of a pseudoenantiomeric aggregate with only one handedness of the helix. The helicity can be preserved by ring-closing olefin metathesis polymerization mediated by Grubbs catalyst when an achiral component with terminal olefinic groups forms the pseudoenantiomeric aggregate in the presence of a tiny amount of the chiral component without olefinic groups. After polymerization and removal of the chiral component, the polymeric architecture obtained from the achiral soldier component is optically active and thus can be regarded as an enantiomeric object in which the chiral information transferred from the chiral sergeant component is preserved. The nanoscale chiral structure is fixed perfectly, as indicated by CD spectroscopic evidence obtained in a polar THF medium at high temperature and low concentration. AFM and TEM observations show a nanoscale fibrous structure with a diameter of 2-4 nm, which corresponds to the molecular size of the triazine triamide monomer.

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Section: Introductionmentioning

confidence: 99%

An Enantiomeric Nanoscale Architecture Obtained from a Pseudoenantiomeric Aggregate: Covalent Fixation of Helical Chirality Formed in Self‐Assembled Discotic Triazine Triamides by Chiral Amplification

Ishi‐i

Kuwahara

Takata

et al. 2006

Chemistry A European J

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“…Let us assume, as is found in one-dimensional aggregates, 34 that the two porphyrin molecules are stacked with their principal symmetry axes aligned with each other and with the direction of intermolecular displacement; for simplicity let us also assume plane polarized laser light propagating along this z direction. References to the character tables for D 2h and D 4h show that in this fixed chromophore case, the only nonzero components of the tensor of either species will be ␣ xx and ␣ yy .…”

Section: Discussionmentioning

confidence: 99%

Single and dual beam optical switching of resonance energy transfer

Andrews

Crisp

2007

The Journal of Chemical Physics

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Through photonic mechanisms based on near-field coupling, laser radiation can engage with resonant energy transfer in a variety of suitably designed materials and molecular structures. Energy that has been acquired, through the initial absorption of resonant laser light, undergoes transfer between chromophores only on the throughput of off-resonant light, the process known as laser-assisted resonance energy transfer. The comprehensive results that are presented here extend and generalize the theory for both single and dual beam configurations, producing results that are applicable to media of various types including doped crystals, heterogeneous multichromophore solids, and solutions. The detailed principles, here explained in terms of both energetics and optical selection rule criteria, are specifically illustrated for a variety of materials. It is shown how general application of the theory can facilitate the elucidation of experiments, by clearly interpreting the effects of laser polarization manipulation. On further analysis of the photophysical mechanisms it is also demonstrated that such effects represent an entirely practicable basis for optical switching and logic gate operation. The additional polarization selectivity afforded by a two-beam setup proves to allow the most complete system control. With such a configuration, there is considerable promise for the realization of new optically driven logic and molecular devices.

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“…Moreover, the synthesis of a given enantiomer can be performed in a stereospecific way. 105,106 The removal of the diacids led also to the formation of enantiopure assemblies. Diastereomeric excess in both the cases was high (de 96%).…”

Section: Formation Of Chiral Structures In a Non-covalent Waymentioning

confidence: 99%