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Impact of Molecular Size and Shape on the Supramolecular Co‐Assembly of Chiral Tricarboxamides: A Comparative Study
Author(s) -
Dorca Yeray,
SánchezNaya Roberto,
Cerdá Jesús,
Calbo Joaquín,
Aragó Juan,
Gómez Rafael,
Ortí Enrique,
Sánchez Luis
Publication year - 2020
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.202002879
Subject(s) - stereocenter , vicinal , chirality (physics) , supramolecular chemistry , steric effects , crystallography , series (stratigraphy) , phenylene , molecule , materials science , stereochemistry , chemistry , physics , enantioselective synthesis , crystal structure , polymer , quantum mechanics , organic chemistry , biology , paleontology , chiral symmetry breaking , quark , nambu–jona lasinio model , catalysis
A comparative investigation of the chiral amplification features of a series of three families of C 3 ‐symmetric tricarboxamides, 1,3,5‐triphenylbenzenetricarboxamides (TPBAs), benzenetricarboxamides (BTAs) and oligo(phenylene ethynylene) tricarboxamides (OPE‐TAs), is here reported. As previously observed for BTAs and OPE‐TAs, a similar dichroic response is obtained for TPBAs decorated with one, two or three chiral side chains bearing stereogenic centers, thus confirming the efficient transfer of point chirality to the supramolecular helical aggregates. Unlike BTAs and OPE‐TAs, the chiral amplification ability of TPBAs in majority rules experiments shows a negligible dependence on the number of chiral centers per monomeric unit, and stands the largest among the series of tricarboxamides. Detailed experimental and theoretical studies demonstrate that the rotation angle between the TPBA units in the helical stack is intermediate to that observed for BTAs and OPE‐TAs. This feature strongly conditions the steric interactions between vicinal molecules in the stack and the final chiral amplification outcome. Furthermore, theoretical calculations show that achiral side chains favor the interdigitation of the helical aggregates and thereby the formation of bundle superstructures.