Waste management of chemically activated switches: using a photoacid to eliminate accumulation of side products.

Molecular switches and machines that are powered by acid-base reactions are susceptible to low switching cycles because of the concomitant formation of waste products during their operation. Here, we demonstrate the fast, efficient, and reversible modulation of a hydrazone switch in methanol using a visible-light activated photoacid, with no generation of side products, high conversion rates (>95%), and no loss of activity over 100 cycles. TEG functionalization of the hydrazone switch allows for the process to be carried with high conversion (>90%) in water as well.

Simple hydrazone building blocks for complicated functional materials.

CONSPECTUS: The ability to selectively and effectively control various molecular processes via specific stimuli is a hallmark of the complexity of biological systems. The development of synthetic structures that can mimic such processes, even on the fundamental level, is one of the main goals of supramolecular chemistry. Having this in mind, there has been a foray of research in the past two decades aimed at developing molecular architectures, whose properties can be modulated using external inputs.