ISSN:
1600-5759
Quelle:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Thema:
Chemie und Pharmazie
,
Geologie und Paläontologie
,
Physik
Notizen:
The crystal structures of the title tryptophan-containing dipeptides, C14H17N3O3·H2O, (I), C13H15N3O3·2H2O, (II), and C13H15N3O3·H2O, (III), respectively, contain at least one water molecule of solvation. As a result, the crystal packing of these compounds is composed of regions of water-mediated hydrogen bonding and tryptophan ring-to-ring stacking separated by the length of the molecule. The tryptophan rings stack in a continuous layer that, when viewed edge-on from the outermost part of the tryptophan ring, exhibits a herring-bone motif. However, owing to the lack of direct overlap of adjacent rings, no degree of π contact or long-range delocalization of ring systems is possible here. The overall molecular conformations of (I) and (III) contain a folding of one peptide over the other, such that a minimum in molecular volume occurs without any intramolecular hydrogen bonding. In these two dipeptides, extensive hydrogen bonding is observed to and from the single water molecule of solvation. In the crystal structure of (II), however, an extended molecule conformation complements a more extensive hydrogen-bonding scheme involving two water molecules of solvation per dipeptide.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1107/S0108270100011926
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