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Synthesis, crystallization, X‐ray structural characterization and solid‐state assembly of a cyclic hexapeptoid with propargyl and methoxyethyl side chains
Author(s) -
Tedesco Consiglia,
Macedi Eleonora,
Meli Alessandra,
Pierri Giovanni,
Della Sala Giorgio,
Drathen Christina,
Fitch Andrew N.,
Vaughan Gavin B. M.,
Izzo Irene,
De Riccardis Francesco
Publication year - 2017
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520617002505
Subject(s) - peptoid , anhydrous , crystallography , hydrogen bond , molecule , side chain , chemistry , crystal structure , crystallization , crystal engineering , hydrate , propargyl , crystal (programming language) , intermolecular force , stereochemistry , supramolecular chemistry , organic chemistry , polymer , peptide , biochemistry , computer science , programming language , catalysis
The synthesis and the structural characterization of a cyclic hexapeptoid with four methoxyethyl and two propargyl side chains have disclosed the presence of a hydrate crystal form [form (I)] and an anhydrous crystal form [form (II)]. The relative amounts of form (I) and form (II) in the as‐purified product were determined by Rietveld refinement and depend on the purification procedures. In crystal form (I), peptoid molecules assemble in a columnar arrangement by means of side‐chain‐to‐backbone C=CH…OC hydrogen bonds. In the anhydrous crystal form (II), cyclopeptoid molecules form ribbons by means of backbone‐to‐backbone CH 2 …OC hydrogen bonds, thus mimicking β‐sheet secondary structures in proteins. In both crystal forms side chains act as joints among the columns or the ribbons and contribute to the stability of the whole solid‐state assembly. Water molecules in the hydrate crystal form (I) bridge columns of cyclic peptoid molecules, providing a more efficient packing.