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Directing Foldamer Self‐Assembly with a Cyclopropanoyl Cap
Author(s) -
Lim Danim,
Kim Hyunjoong,
Gong Jintaek,
Eom JaeHoon,
Yoon Eunyoung,
Driver Russell W.,
Baik MuHyun,
Lee HeeSeung
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201805783
Subject(s) - foldamer , synthon , self assembly , hydrogen bond , supramolecular chemistry , chemistry , intermolecular force , crystallography , rational design , non covalent interactions , peptide , stereochemistry , protein secondary structure , structural motif , nanotechnology , molecule , combinatorial chemistry , materials science , crystal structure , organic chemistry , biochemistry
Abstract The rational design of self‐assembling organic materials is extremely challenging due to the difficulty in precisely predicting solid‐state architectures from first principles, especially if synthons are conformationally flexible. A tractable model system to study self‐assembly was constructed by appending cyclopropanoyl caps to the N termini of helical α/β‐peptide foldamers, designed to form both N−H⋅⋅⋅O and C α −H⋅⋅⋅O hydrogen bonds, which then rapidly self‐assembled to form foldectures (foldamer architectures). Through a combined analytical and computational investigation, cyclopropanoyl capping was observed to markedly enhance self‐assembly in recalcitrant substrates and direct the formation of a single intermolecular N−H⋅⋅⋅O/C α −H⋅⋅⋅O bonding motif in single crystals, regardless of peptide sequence or foldamer conformation. In contrast to previous studies, foldamer constituents of single crystals and foldectures assumed different secondary structures and different molecular packing modes, despite a conserved N−H⋅⋅⋅O/C α −H⋅⋅⋅O bonding motif. DFT calculations validated the experimental results by showing that the N−H⋅⋅⋅O/C α −H⋅⋅⋅O interaction created by the cap was sufficiently attractive to influence self‐assembly. This versatile strategy to harness secondary noncovalent interactions in the rational design of self‐assembling organic materials will allow for the exploration of new substrates and speed up the development of novel applications within this increasingly important class of materials.