Visible Light‐Driven Molecular Switches and Motors: Recent Developments and Applications

Abstract

Inspired by human vision, a diverse range of light‐driven molecular switches and motors have been developed for fundamental understanding and application in material science and biology. Recently, the design and synthesis of visible light‐driven molecular switches and motors have been actively pursued. This emerging trend is partly motivated to avoid the harmful effects of ultraviolet light, which was necessary to drive the classical molecular switches and motors at least in one direction, impeding their employment in biomedical and photopharmacology applications. Moreover, visible light‐driven molecular switches and motors are demonstrated to enable benign optical materials for advanced photonic devices. Therefore, during the past several years, visible light‐driven molecular switches based on azobenzene derivatives, diarylethenes, 1,2‐dicyanodithienylethenes, hemithioindigo derivatives, iminothioindoxyls, donor‐acceptor Stenhouse adducts, and overcrowded alkene based molecular motors have been judiciously designed, synthesized, and used in the development of functional materials and systems for a wide range of applications. In this Review, we present the recent developments toward the design of visible light‐driven molecular switches and motors, with their applications in the fabrication of functional materials and systems in material science, bioscience, pharmacology, etc. The visible light‐driven molecular switches and motors realized so far undoubtedly widen the scope of these interesting compounds for technological and biological applications. We hope this Review article could provide additional impetus and inspire further research interests for future exploration of visible light‐driven advanced materials, systems, and devices.

Conformational Switch of Benzanilide Derivative Induced by Acid; Effect of Pentafluorobenzoyl Group

“…IR (KBr): 3248, 3174, 3059, 2922, 2810, 1662, 1599 cm −1 . EI-LRMS m/z: M + 331 (15), 330(94), 329 (9), 195 (10), 167 (5), 137(2), 136 (9), 135(100), 119 (6), 108 (3). EI-HRMS: calcd for C 15 H 11 F 5 N 2 O [M + ], 330.0786; found, 330.0791.…”

“…Various linker group was applied as light-controlled molecular switches. However, diversities of linker group whose conformation is controlled other than light had been relatively limited. , Amide bonds is a promising candidate since amide bonds form the backbone of proteins which can be regarded as biological molecular machines.…”

Stepping Out of the Blue: From Visible to Near‐IR Triggered Photoswitches

“…Encouragingly, the desire to exploit visible/NIR lighttriggered photoisomerization has greatly motivated researchers over the last decade to develop strategies to redshift the absorbance wavelengths of both isomers to enable fully bidirectional photoswitching operating with visible and NIR light. [13,[56][57][58][59] In Sections 2-4 of this Review, we showcase several families of photoswitches, classified by distinct photochromic reaction mechanisms, for which significant progress in the development of visible-and NIR-switchable analogues has been reported (Figure 1). For each class, we examine the key photochromic properties, such as photoconversion efficiency, isomerization quantum yields, the thermal half-lives of the thermodynamically less stable isomers, and the resistance of the systems to photofatigue, highlighting the strengths and weaknesses in each case.…”

Linear and Nonlinear Optical Properties of Azobenzene Derivatives Modified with an (Amino)naphthalene Moiety

“…The interest in development of molecular switches 1 − 6 arises from the fact that imparting external sensitivity to molecular systems is an efficient way to control on-demand their structure, properties, and functions and hence offers multiple applications in materials 7 − 11 and biological sciences. 12 − 15 Among various external triggers, light is the most desired kind of stimulus, because spatiotemporal resolution, excitation tunability, and biocompatibility are achieved through remote control.…”