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

Abstract

Light offers unique opportunities for controlling the activity of materials and biosystems with high spatiotemporal resolution. Molecular photoswitches are chromophores that undergo reversible isomerization between different states upon irradiation with light, allowing a convenient means to control their influence over the system of interest. However, a significant limitation of classical photoswitches is the requirement to initiate the switching in one or both directions using deleterious UV light with poor tissue penetration. Red-shifted photoswitches are hence in high demand and have attracted keen recent research interest. In this Review, we highlight recent progress towards the development of visible-and NIR-activated photoswitches characterized by distinct photochromic reaction mechanisms. We hope to inspire further endeavors in this field, allowing the full potential of these tools in biotechnology and materials chemistry applications to be realized.

Energy‐Transfer Photocatalysis Using Lead Halide Perovskite Nanocrystals: Sensitizing Molecular Isomerization and Cycloaddition

“…[16a] Secondly, the close-DAE should have lower triplet energy than the open-DAE, and therefore the former can also accept triplet energy from photoexcited NCs, resulting in sensitized ring-opening. [34] The decrease in the CY is especially obvious under high-power (2.7 W) illumination. As shown in Figure S10, in this case the CY reaches maximum at � 5 seconds and rapidly decreases.…”

Photoswitchable molecular tweezers: isomerization to control substrate binding, and what aboutvice versa?

“…9 Part of the work in this field is inspired by the dynamic functions of proteins, such as the regulation of solute transport across the cell membrane. Imitation of this in synthetic systems may result in physiological tools and therapeutic agents 8,10 to respectively study and treat diseases that have been associated to malfunctioning protein transporters [ e.g. , mutations in the gene encoding for cystic fibrosis transmembrane conductance regulator (CFTR) protein leads to dysregulation of chloride translocation].…”

“…The mode of operation of these photoswitches has been summarized in other accounts. 8 The emphasis here lies on their suitability for use as backbone of photoswitchable molecular tweezers, which is discussed per class of photoswitch in each of the sections.…”

A general approach for all-visible-light switching of diarylethenes through triplet sensitization using semiconducting nanocrystals

“…In addition, the penetration depth in tissue is very poor, which is a severe downside considering the potential use of these switches in photopharmacology. 24,25 Many research efforts have been attributed to design all-visible-light activated DAEs, 26,27 such as shifting the absorption spectrum by chemically extending the π conjugation, 28,29 or using upconverting nanoparticles that absorb in the visible or near-infrared region to generate UV light to drive the photoisomerization. 30,31 However, directly shifting the absorption band of DAEs requires complicated synthesis, while the low efficiency of the upconverting process leads to overall low photoisomerization efficiencies.…”