Academic Journal
Proposed modification to a muscle-like acid-base switchable [2](2)rotaxane for improved force delivery.
| Title: | Proposed modification to a muscle-like acid-base switchable [2](2)rotaxane for improved force delivery. |
|---|---|
| Authors: | Dinh, Tina T.1 (AUTHOR) ttd44@drexel.edu, Bazargan, Gloria1,2 (AUTHOR), Sohlberg, Karl1 (AUTHOR) |
| Source: | Molecular Simulation. Jan2024, Vol. 50 Issue 1, p55-62. 8p. |
| Abstract: | Switchable rotaxanes are good candidates for molecular machines because of their ability to undergo reversible and repeatable co-conformational isomerism in response to an external stimulus. An acid-base switchable [2](2)rotaxane reported by Li et al. [J Org Chem. 79(15): [6996–7004] has been reported to exhibit a 48% change in length upon a stimulus-induced change in protonation state, suggesting that it could serve as the fundamental element of a 'molecular muscle'. In the present work, the mechanical behaviour of this topologically complex system is explored with calculations based on semiempirical electronic structure theory. Our calculations predict that the original system will not work as envisioned. Although the calculations confirm a 48% change in length, they also reveal an energy barrier to ring shuttling upon deprotonation, preventing the immediate delivery of force. Therefore, a modification to the system is proposed. Similar semiempirical calculations were carried out on the modified system and the force calculated. The average force generated from the modified system is predicted to be approximately −86 pN. The results demonstrate that the proposed modification reduces the force generated by ring shuttling by 11% but largely eliminates the energy barrier to ring shuttling so that the force is immediately available. [ABSTRACT FROM AUTHOR] |
| Subject Terms: | *ACTIVATION energy, *STRUCTURAL analysis (Engineering), *ISOMERISM, *ELECTRONIC structure, *PROTON transfer reactions |
| ISSN: | 08927022 |
| DOI: | 10.1080/08927022.2023.2272635 |
| Database: | Academic Search Index |