Homogeneous Catalysts with a Mechanical ("Machine-like") Action

Chemical reactions may be controlled by either: 1)the minimum threshold energy that must be overcome during collisions between reactant molecules/atoms (the activation energy, E(a)) or: 2)the rate at which reactant collisions occur (the collision frequency, A)-for reactions with low E(a). Reactions of type 2 are governed by the physical, mechanical interaction of the reactants. Such mechanical processes are unusual, but not unknown in molecular catalysts. In this work we examine the machine-like nature of the action in various abiological mechanical catalysts and consider the implications for mimicry of biological catalysts.