A Covalent Organic Helical Cage with Remarkable Chiroptical Amplification

Sandra Míguez-Lago; Antonio L Llamas-Saiz; M Magdalena Cid; J Lorenzo Alonso-Gómez

doi:10.1002/chem.201503994

A Covalent Organic Helical Cage with Remarkable Chiroptical Amplification

Chemistry. 2015 Dec 7;21(50):18085-8. doi: 10.1002/chem.201503994. Epub 2015 Nov 3.

Authors

Sandra Míguez-Lago¹, Antonio L Llamas-Saiz², M Magdalena Cid³, J Lorenzo Alonso-Gómez⁴

Affiliations

¹ Departamento de Química Orgánica, Universidade de Vigo, Lagoas-Marcosende s/n, Vigo, 36310 (Spain).
² Unidade de Raios X. RIAIDT, Universidade de Santiago de Compostela, Santiago de Compostela, 15782 (Spain).
³ Departamento de Química Orgánica, Universidade de Vigo, Lagoas-Marcosende s/n, Vigo, 36310 (Spain). mcid@uvigo.es.
⁴ Departamento de Química Orgánica, Universidade de Vigo, Lagoas-Marcosende s/n, Vigo, 36310 (Spain). lorenzo@uvigo.es.

PMID: 26449173
DOI: 10.1002/chem.201503994

Abstract

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.

Keywords: chirality; circular dichroism; helicity; host-guest; molecular cages.

Publication types

Research Support, Non-U.S. Gov't