Trans-2-aminocyclohexanols as pH-triggered molecular switches

Vyacheslav V Samoshin,Elena K Dobretsova,Hans-Jörg Schneider,Alla K Shestakova,Vyacheslav A Chertkov,Dmitriy E Gremyachinskiy,Lidia P Vatlina,Barbora Brazdova,Christian V Stevens

doi:10.3998/ark.5550190.0006.410

Vyacheslav V Samoshin, Elena K Dobretsova + Show 7 more

Open Access

https://doi.org/10.3998/ark.5550190.0006.410

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Abstract

Cyclohexane-based conformationally controlled ionophores, the emerging new class of molecular switches, provide a new and promising approach to allosteric systems with negative cooperativity. Protonation of trans-2-aminocyclohexanols leads to dramatic conformational changes: due to an intramolecular hydrogen bond, a conformer with equatorial position of ammonio- and hydroxy-groups becomes predominant. Thus, these structures can serve as powerful conformational pH-triggers. The trans-2-aminocyclohexanol moiety has been used for pH-triggered conformational switching of a crown ether and a podand, and their complexes with potassium ion.

Highlights

The development of molecular switches is of great current interest in view of their possible use in many applications, such as drug release, new sensor techniques or information storage and transmission
As we suggested in a preliminary publication,[23] another way to control such a conformational equilibrium is an addition of acid to protonate the amino group, and to generate a stronger intramolecular hydrogen bond of O⋅⋅⋅H-N+ type,[23,39] e.g. in 3A (Scheme 3).[23]
The results of the present study prove that the trans-2-aminocyclohexanol moiety can be used as a conformational pH-trigger for the control of the complex formation by various crown ethers and podands via switching of their preferred conformation

Summary

Introduction

The development of molecular switches is of great current interest in view of their possible use in many applications, such as drug release, new sensor techniques or information storage and transmission. As we suggested in a preliminary publication,[23] another way to control such a conformational equilibrium is an addition of acid to protonate the amino group, and to generate a stronger intramolecular hydrogen bond of O⋅⋅⋅H-N+ type,[23,39] e.g. in 3A (Scheme 3).[23] This bond would stabilize conformation 3A, moving the ester groups away from each other, and decreasing their potential ability to interact with another molecule or ion, for example to form complexes like 1B.

Results

Conclusion