Moving systems of polar dimeric capsules out of thermal equilibrium by light irradiation

Abstract

Heterodimeric capsules self-assembled from tetraurea calix[4]pyrrole and tetraurea calix[4]arene provide unique molecular containers for the organised inclusion of small polar molecules. By inserting stimuli-responsive groups (azobenzene) in the heterocapsule structure, we are able to modify the equilibrium state of the system or the exchange between different host-guest assemblies in a reversible manner.

Drug Delivery by Controlling a Supramolecular Host–Guest Assembly with a Reversible Photoswitch

“…This has led to viable approaches towards intelligent supramolecular materials, molecular information processing, the release/capture of compounds in bio‐inspired applications, and drug‐delivery systems . Among other stimuli, such as chemical and electrochemical signals, the use of light has been a preferred choice due to the possibility of conducting spatiotemporally and remotely controlled experiments . Our own efforts in this field have focused on supramolecular complexes with cucurbituril hosts and their manipulation by means of photoinduced pH jumps .…”

“…[6][7][8][9][10][11] Among other stimuli,s uch as chemical and electrochemicals ignals, the use of light has been ap referred choice due to the possibility of conducting spatiotemporally and remotely controlled experiments. [1,[12][13][14][15][16] Our own efforts in this field have focused on supramolecular complexes with cucurbituril hosts and their manipulation by means of photoinduced pH jumps. [17,18] The choice of cucurbiturils as hostm acrocycles for these applications is motivated by their unique supramolecular chemistry,i ncludinge xtraordinary high binding constants for avariety of organic guests in water.…”

Chemical Communication between Molecules

“…Likewise, also the host can be equipped with a photoisomerizable group, enabling the opening or closing of a capsule. Such systems were reported, for example, by the Ballester group, drawing on calix[4]arenes with appended azobenzenes as light‐sensitive units of self‐assembled capsules . These light‐responsive assemblies could be potentially implemented for chemical communication.…”

Synthesis and Binding Studies of a Tetra‐α Aryl‐Extended Photoresponsive Calix[4]pyrrole Receptor Bearing meso‐Alkyl Substituents

“…Lately, our research group produced tetraurea‐aryl‐extended calix[4]pyrroles with terminal azobenzene groups demonstrating their capacity to self‐assemble in photoresponsive homo‐ and heterodimeric capsules , …”