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A Covalent Organic Helical Cage with Remarkable Chiroptical Amplification
Author(s) -
MíguezLago Sandra,
LlamasSaiz Antonio L.,
Magdalena Cid M.,
AlonsoGómez J. Lorenzo
Publication year - 2015
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.201503994
Subject(s) - covalent bond , chemistry , cage , molecule , chirality (physics) , crystallography , stereochemistry , organic chemistry , physics , chiral symmetry , mathematics , combinatorics , quantum mechanics , nambu–jona lasinio model , quark
Purely organic shape‐persistent chiral cages are designed through the use of rigid chiral axes. Covalent dimerization of a tripodal fragment bearing chiral allenes forms a molecular twisted prism with loop‐like lateral edges presenting 10‐fold chiroptical amplification compared to its isolated building blocks. The expected geometry of covalent organic helical cage ( M,M ) 3 ‐ 1 was confirmed by X‐ray crystal structure analysis. Comparison of the chiroptical responses of this shape‐persistent molecular container with more flexible analogues highlights how the control of the conformational freedom of the molecule can be used to obtain molecular cages with strong chiroptical responses. Selective inclusion‐complex formation with ferrocenium ions [( P,P ) 3 ‐ 1 @Fc + ] was confirmed and quantified with HR‐ESI‐MS and NMR spectroscopy.