Reversible Soft Mechanochemical Control of Biaryl Conformations through Crosslinking in a 3D Macromolecular Network |
| |
Authors: | Dr Julien B Kelber Dr Amina Bensalah-Ledoux Dr Sarah Zahouani Dr Bruno Baguenard Prof Dr Pierre Schaaf Dr Alain Chaumont Prof Dr Stephan Guy Prof Dr Loïc Jierry |
| |
Institution: | 1. Université de Strasbourg, CNRS, Institut Charles Sadron (UPR22), 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France;2. Université Claude Bernard Lyon 1, Université de Lyon, CNRS, Institut Lumière Matière (UMR5306), 69622 Lyon, France;3. Université de Strasbourg, Faculté de Chimie, UMR7140, 1 rue Blaise Pascal, 67008 Strasbourg Cedex, France |
| |
Abstract: | Tuning the dihedral angle (DA) of axially chiral compounds can impact biological activity, catalyst efficiency, molecular motor performance, or chiroptical properties. Herein, we report gradual, controlled, and reversible changes in molecular conformation of a covalently linked binaphthyl moiety within a 3D polymeric network by application of a macroscopic stretching force. We managed direct observation of DA changes by measuring the circular dichroism signal of an optically pure BINOL-crosslinked elastomer network. Stretching the elastomer resulted in a widening of the DA between naphthyl rings when the BINOL was doubly grafted to the elastomer network; no effect was observed when a single naphthyl ring of the BINOL was grafted to the elastomer network. We have determined that ca. 170 % extension of the elastomers led to the transfer of a mechanical force to the BINOL moiety of 2.5 kcal mol−1 Å−1 (ca. 175 pN) in magnitude and results in the opening of the DA of BINOL up to 130°. |
| |
Keywords: | chirality circular dichroism conformation mechanochemistry stimulus-responsive materials |
|
|