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Bridging the current gap between the precision and efficiency demonstrated by natural systems and synthetic materials requires interfacing and independently controlling multiple stimuli-responsive building blocks in a single platform. The mentioned orthogonal control over material properties (i.e., the ability to selectively activate one stimuli-responsive moiety without affecting another) could pave the way for a multitude of applications, including logic-gated optoelectronics, on-demand drug delivery platforms, and molecular shuttles, for example. In this Review, we highlight the recent successful strategies to achieve orthogonal control over material properties using a combination of stimuli-responsive building blocks and multiple independent stimuli. We begin by surveying the fundamental studies of multi-stimuli-responsive systems, which utilize a variety of stimuli to activate a single stimuli-responsive moiety (e.g., spiropyran, diarylethene, or dihydroazulene derivatives), because these studies lay the foundation for the design of systems containing more than one independently controlled fragment. As a next step, we overview the emerging field focusing on systems which are composed of more than one unique stimuli-responsive unit that can respond to independent stimuli, including distinct excitation wavelengths, or a combination of light, heat, pH, potential, or ionic strength. Recent advances clearly demonstrate how strategic coupling of orthogonally controlled stimuli-responsive units can allow for selective modulation of a range of material properties, such as conductivity, catalytic performance, and biological activity. Thus, the highlighted studies foreshadow the emerging role of materials with orthogonally controlled properties to impact the next generation of photopharmacology, nanotechnology, optoelectronics, and biomimetics.
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Traffic Lights for Catalysis: Stimuli‐Responsive Molecular and Extended Catalytic Systems
Abstract The advances made in the field of stimuli‐responsive catalysis during the last five years with a focus on the novel recently‐emerged directions and applications have been surveyed. Metal‐free catalysts and organometallic complexes, as well as biomimetic systems and extended structures, which display switchable catalytic activity for a variety of organic transformations, are discussed. Light‐activated systems comprised of photochromic molecules capable of modulating reaction rate, yield, or enantioselectivity based on geometric and electronic changes associated with photoisomerization are the focus of the detailed discussion. Alternative stimuli, including pH and temperature, which could be applied either alone or in combination with light, are also addressed. Recent advances clearly demonstrate that the capability to finely tune catalyst behavior via an external stimulus is a powerful tool that could alter the landscape of sustainable chemistry.
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- Award ID(s):
- 2103722
- PAR ID:
- 10419012
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 62
- Issue:
- 29
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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