Orthogonal Initiation of Molecular Motion Devices by Two Chemical Fuels

J Am Chem Soc. 2023 Dec 13;145(49):26520-26524. doi: 10.1021/jacs.3c08134. Epub 2023 Nov 29.

Abstract

Herein, we demonstrate the selective dissipative and orthogonal actuation of two distinct molecular devices controlled by alternate fuel use. When the multicomponent ensemble of [2]rotaxane 1 and turnstile [Cu(2)(3)]+ was charged with AgBF4 as chemical fuel (Fuel 1) together with NEt3/PhCH2Br (cofuels), the transiently formed [Ag(1)]+ showed a stochastic shuttling of the silver macrocycle between two degenerate triazole stations on the thread (k298 = 1.2 × 105 s-1), whereas [Cu(2)(3)]+ was unperturbed. Instead, treatment of the mixture with PPh3 as an alternative fuel (Fuel 2) in the presence of oxidant 4 (cofuel) generated the complex [Cu(3)(PPh3)2]+ and transient thermal motion in rotor 2 (k298 = 4.9 × 104 s-1), whereas rotaxane 1 stayed dormant. Thus, two distinct chemical fuels selectively and orthogonally activated two distinct transient motion devices from a multicomponent mixture. In total, four interference-free dissipative cycles were demonstrated by using alternating fuel additions.