Cucurbit[7]uril: A High-Affinity Host for Encapsulation of Amino Saccharides and Supramolecular Stabilization of Their α-Anomers in Water

Authors

  • Yoonjung Jang,

    1. Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 790-784 (Republic of Korea)
    2. Department of Chemistry, and Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 790-784 (Republic of Korea) http://csc.ibs.re.kr/
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  • Dr. Ramalingam Natarajan,

    Corresponding author
    1. Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700032 (India)
    • Ramalingam Natarajan, Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700032 (India)

      Kimoon Kim, Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 790-784 (Republic of Korea)

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  • Dr. Young Ho Ko,

    1. Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 790-784 (Republic of Korea)
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  • Prof. Dr. Kimoon Kim

    Corresponding author
    1. Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 790-784 (Republic of Korea)
    2. Department of Chemistry, and Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 790-784 (Republic of Korea) http://csc.ibs.re.kr/
    • Ramalingam Natarajan, Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata, 700032 (India)

      Kimoon Kim, Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 790-784 (Republic of Korea)

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  • This work was supported by the Institute for Basic Science (IBS) [CA1303]. R.N. thanks SERB, Department of Science and Technology (DST), India, for a Ramanujan Fellowship.

Abstract

Cucurbit[7]uril (CB[7]), an uncharged and water-soluble macrocyclic host, binds protonated amino saccharides (D-glucosamine, D-galactosamine, D-mannosamine and 6-amino-6-deoxy-D-glucose) with excellent affinity (Ka=103 to 104M−1). The host–guest complexation was confirmed by NMR spectroscopy, isothermal titration calorimetry (ITC), and MALDI-TOF mass spectral analyses. NMR analyses revealed that the amino saccharides, except D-mannosamine, are bound as α-anomers within the CB[7] cavity. ITC analyses reveal that CB[7] has excellent affinity for binding amino saccharides in water. The maximum affinity was observed for D-galactosamine hydrochloride (Ka=1.6×104M−1). Such a strong affinity for any saccharide in water using a synthetic receptor is unprecedented, as is the supramolecular stabilization of an α-anomer by the host.

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