X-ray diffraction evidence for aromatic π hydrogen bonding to water
The interaction of water with aromatic moieties is of importance in biological systems, as most encounter an aqueous environment during their normal functions. For example, common constituents of globular proteins such as phenylalanine, tryptophan and tyrosine possess aromatic side-chains1 that may...
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Published in | Nature (London) Vol. 349; no. 6311; pp. 683 - 684 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing
21.02.1991
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | The interaction of water with aromatic moieties is of importance in biological systems, as most encounter an aqueous environment during their normal functions. For example, common constituents of globular proteins such as phenylalanine, tryptophan and tyrosine possess aromatic side-chains1 that may encounter water molecules inside the protein structure2. As a model for hydrogen-bonding interactions with aromatics, we have performed X-ray diffraction studies on crystalline Na4[calix[4]arene sulphonate]-13.5H20. Calixarene molecules3'4 contain hydrophobic cavities comprised of aromatic groups, rimmed, in the case of the water-soluble sulphonates (R = -S03Na), by hydrophilic groups5,6. In the absence of a hydrophobic guest, the cavity invariably contains a water molecule. The low-temperature X-ray crystal structure of this compound (see Table 1 and Fig. 1) shows direct evidence for hydrogen bonding between water and the aromatic it electrons in the solid state. |
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ISSN: | 0028-0836 1476-4687 |
DOI: | 10.1038/349683a0 |