Double Rotors with Fluxional Axles: Domino Rotation and Azide–Alkyne Huisgen Cycloaddition Catalysis

The simple preparation of the multicomponent devices [Cu(4)(A)(2)](4+) and [Cu(2)(A)(B)](2+), both rotors with fluxional axles undergoing domino rotation, highlights the potential of self‐sorting. The concept of domino rotation requires the interconversion of axle and rotator, allowing the spatiotemporal decoupling of two degenerate exchange processes in [Cu(4)(A)(2)](4+) occurring at 142 kHz. Addition of two equiv of B to rotor [Cu(4)(A)(2)](4+) afforded the heteromeric two‐axle rotor [Cu(2)(A)(B)](2+) with two distinct exchange processes (64.0 kHz and 0.55 Hz). The motion requiring a pyridine→zinc porphyrin bond cleavage is 1.2×10(5) times faster than that operating via a terpyridine→[Cu(phenAr(2))](+) rupture. Finally, both rotors are catalysts due to their copper(I) content. The fast domino rotor (142 kHz) was shown to suppress product inhibition in the catalysis of the azide–alkyne Huisgen cycloaddition.