Light‐driven Rotary Molecular Motors for Out‐of‐Equilibrium Systems

Abstract

Less than 150 years since De Lavoisier laid the foundations of modern chemistry, chemists have created a marvelous diversity of molecules and accumulated an unimaginable wealth of information on materials. NMR and MS techniques allow us to determine exact molecular compositions within minutes, scanning tunneling microscopy allows us to look at individual atoms [1], and advanced spectroscopic methods and X-ray crystallography can establish the exact 3D structure of complex proteins and their binding pockets [2], after which structure-based design can be used to prepare a drug tailor made to fit that pocket [3]. However, the days of chemistry as the science of the single molecule have long passed, as evident from the rise of, e.g. supramolecular chemistry. The boundaries between chemistry and physics or biology have all but disappeared, and chemistry is no longer restrained to the nanoscale. By joining forces with other disciplines, we are able to traverse length scales and understand the properties of matter anywhere between the pico-and the macroscale. Bottom-up design of molecules and the interaction between larger assemblies let us create new materials, tailor made for their envisioned application by translating molecular properties to real-life functions.Responsive or "smart" materials can change their properties in response to an external trigger and by now are able to perform the most amazing tasks. Self-healing materials autonomously repair damage [4], soft actuators perform biomimetic tasks on the macroscale [5], and smart drug delivery systems can circumvent the devastating side effects associated with some treatments [6]. In the continuing quest to create more advanced materials, achieving mechanical actuation and other lifelike motion at the macroscale is a major landmark, and some inspiring examples have been reported [7,8]. However, many of these responsive systems are limited to reversible (switching) motion in which no net work is generated. If the ultimate goal is to create a smart material capable of performing real work at the nanoscale, chemists need to take inspiration from nature. In contrast to the vast majority of Out-of-Equilibrium (Supra)molecular Systems and Materials, First Edition. Edited by Nicolas Giuseppone and Andreas Walther.