Abstract
Bambusurils (BUs) are known to be rigid cavitands that feature an extended, jigger-like conformation, and the BU[6]s strongly bind anions within their hydrophobic cavity. These features are not necessarily shared by the family of perthio-BUs. This study reveals that perthio-BUs assume a compact conformation and perthio-BU[6]s are poor anion binders, crystallizing as anion-free species from solutions containing halide salts. Computational studies show that the equatorial sulfur atoms compete against guest anions for binding with the glycoluril methine groups via strong van der Waals (vdW) attractive interactions. These competitive contacts not only account for the diminished anion-binding of perthio-BUs, but also explain their compact conformation. The semithio- and perthio-BU[4]s form linear coordination polymers with HgII in the solid-state regardless of their intrinsic molecular conformation. The strong involvement of sulfur atoms in intramolecular interactions differentiates the equatorial from the axial (peripheral) heteroatoms, thus offering chemoselective and regioselective transformations.
Original language | English |
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Pages (from-to) | 13336-13343 |
Number of pages | 8 |
Journal | Chemistry - A European Journal |
Volume | 25 |
Issue number | 58 |
DOIs | |
State | Published - 17 Oct 2019 |
Bibliographical note
Funding Information:We are grateful for financial support by the Israel Ministry of Science Technology and Space (MOST) grant No. 3‐10855 and the Open University of Israel (OUI). We thank Dr. Sofiya Kolusheva of the Ilse Katz Institute for Nanoscale Science and Technology at Ben‐Gurion University of the Negev for the ITC measurements. We also thank Dr. Limor Frish, director of the NMT laboratories at Tel‐Aviv University, for the NMR diffusion experiments.
Funding Information:
We are grateful for financial support by the Israel Ministry of Science Technology and Space (MOST) grant No. 3-10855 and the Open University of Israel (OUI). We thank Dr. Sofiya Kolusheva of the Ilse Katz Institute for Nanoscale Science and Technology at Ben-Gurion University of the Negev for the ITC measurements. We also thank Dr. Limor Frish, director of the NMT laboratories at Tel-Aviv University, for the NMR diffusion experiments.
Publisher Copyright:
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Keywords
- anion receptors
- bambusuril
- cavitands
- host–guest chemistry
- sulfur ligands