Orthogonal Initiation of Molecular Motion Devices by Two Chemical Fuels

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.