Abstract
Confining molecules to volumes only slightly larger than the molecules themselves can profoundly alter their properties. Molecular switches—entities that can be toggled between two or more forms upon exposure to an external stimulus—often require conformational freedom to isomerize. Therefore, placing these switches in confined spaces can render them non-operational. To preserve the switchability of these species under confinement, we work with a water-soluble coordination cage that is flexible enough to adapt its shape to the conformation of the encapsulated guest. We show that owing to its flexibility, the cage is not only capable of accommodating—and solubilizing in water—several light-responsive spiropyran-based molecular switches, but, more importantly, it also provides an environment suitable for the efficient, reversible photoisomerization of the bound guests. Our findings pave the way towards studying various molecular switching processes in confined environments.
Highlights
Confining molecules to volumes only slightly larger than the molecules themselves can profoundly alter their properties
We investigated the binding and photoinduced structural transformations of a model light-responsive molecular switch, spiropyran, within a flexible coordination cage
We showed that the encapsulation of different spiropyrans in a hydrophobic cavity of the cage was accompanied by spontaneous switching to an otherwise unstable, colored isomer, highlighting the cage’s capacity to revert the relative stability of different isomers of the same molecule.[40]
Summary
Confining molecules to volumes only slightly larger than the molecules themselves can profoundly alter their properties. Molecular switches—entities that can be toggled between two or more forms upon exposure to an external stimulus—often require conformational freedom to isomerize Placing these switches in confined spaces can render them non-operational. We show that owing to its flexibility, the cage is capable of accommodating—and solubilizing in water—several light-responsive spiropyran-based molecular switches, but, more importantly, it provides an environment suitable for the efficient, reversible photoisomerization of the bound guests. It has long been recognized that placing azobenzene within densely packed self-assembled monolayers[24] or inside coordination cages[25] renders it non-switchable In another system, spiropyran residing in the cavity of a dimeric capsule held together by hydrogen bonds could be successfully isomerized, but at the expense of the disintegration of the supramolecular host[26]. Taking advantage of these findings, we develop two time-sensitive information storage media: a paper, on which writing can be performed using water as the ink, and a gel, which can be reversibly patterned using light
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
