Mechanical Force for the Transformation of Aziridine into Imine

Abstract

Force‐selective mechanochemical reactions may be important for applications in polymer mechanochemistry, yet it is difficult to achieve such reactions. This paper reports that cis‐N‐phthalimidoaziridine incorporated into a macromolecular backbone undergoes migration of N‐phthalimido group to afford imine under mechanochemical condition and not thermal one. The imine is further hydrolyzed by water bifurcating into amine and aldehyde. These structural transformations are confirmed by 1H NMR and FT‐IR spectroscopic analyses. Computational simulations are conducted for the aziridine mechanophore to propose the mechanism of reaction and define the substrate scope of reaction.

Single-Molecule Junction: A Reliable Platform for Monitoring Molecular Physical and Chemical Processes

“…Recently, the regulation of molecular conformation by mechanical force has gradually become a burgeoning interdisciplinary subject, including mechanical discoloration, , mechanical catalysis, small molecule release, force-induced stress enhancement, and mechanical luminescence . Single-molecule devices represented by metal junctions provide a favorable platform for in-depth research in this field because of their characteristic structural advantages.…”

Polymer mechanochemistry for the release of small cargoes

“…For example, upon ultrasonication, the aziridine-based mechanophore developed by the Yoon group recently went through a mechanochemical transformation to afford the imine derivative that was easily hydrolysed by water to degrade the polymers. 30…”

“…For example, upon ultrasonication, the aziridinebased mechanophore developed by the Yoon group recently went through a mechanochemical transformation to afford the imine derivative that was easily hydrolysed by water to degrade the polymers. 30 Release of small organic fluorescent molecules. In 2019, Robb et al utilized DFT calculations to design a furan-maleimide adduct that undergoes a retro-Diels-Alder reaction under mechanical force to generate a metastable furfuryl carbonate intermediate (Fig.…”

“…Over the past decade, polymer mechanochemistry has attracted increasing attention because it can not only be utilized to make a variety of functional materials at the macroscopic level, but also provides a useful tool to enable fundamental studies on specially force-coupled reactivities of mechanophores at the molecular level. Mechanophores, which are force-sensitive moieties embedded in polymer chains, are the key points to transduce mechanical energy into various physical and chemical responses of polymeric materials, such as color or fluorescence change, [8][9][10][11][12][13] generation of reactive species, [14][15][16] triggering of crosslinking [17][18][19] or catalysis, [20][21][22][23] conductivity change, 24,25 achieving controllable degradation, [26][27][28][29][30] and the release of small molecule cargoes including both small molecules 26,[31][32][33][34][35][36][37][38][39][40][41][42] and metal ions. [43][44][45][46] Among these force-induced responses, the release of small molecule cargoes is relatively unexplored but offers fantastic opportunities to prepare different functional materials for various application purposes.…”

“…In contrast to healing, the released small cargoes also have the potential to trigger the depolymerization of polymers, and the mechanophore in this context serves as a gate to control the degradation of the material. [26][27][28][29][30]48 Additionally, tensile force can be obtained by simple daily motions such as muscle tension, and ultrasound can be easily regulated to control its penetration depth, so mechanophores also have great potential to be used to controlled drug release if the small cargoes are drugs. 49 In this highlight article, we specifically discuss the recent developments in the mechanochemical release of small cargoes that are directly unloaded from mechanophores.…”