Multiresponsive Donor–Acceptor Stenhouse Adduct: Opportunities Arise from a Diamine Donor

Abstract

A new donor–acceptor Stenhouse adduct based on a N,N,N′-trimethylethylenediamine donor has been reported. An unprecedented isomer has been isolated, and rich conversions between three isomers have been achieved upon visible-light irradiation or base/acid stimuli. The drastic color change associated with structural conversion has been utilized to selectively sense volatile primary amines as well as high-charged hard Lewis acids (Sc3+, Ti4+, Cr3+, and Al3+).

Promoting the Furan Ring‐Opening Reaction to Access New Donor–Acceptor Stenhouse Adducts with Hexafluoroisopropanol

“…Presumably,this results from nucleophilic attack on the triene and/or 1,4-addition to the cyclopentenone closed form. [19,20] Besides long reaction times,p urification can also be am ajor challenge.P urification of DASA photochromes often relies on trituration or precipitation of the more hydrophobic open form, which takes advantage of the solubility differences between the open and closed form of DASAs and the corresponding degradation products.C ommon purification methods such as column chromatography are often lowyielding,p redominantly because of the conversion between the open and closed form that occurs during purification. This challenge is highlighted by the low yields (typically < 50 %) [11,12] observed for the synthesis of second generation DASAs.D ecreasing the required reaction time,s implifying the purification of DASAs,and expanding the design space to enable the use of unreactive donors or acceptors would, therefore,f urther expand the utility of this new class of photochromes.…”

New Donor-Acceptor Stenhouse Adducts as Visible and Near Infrared Light Polymerization Photoinitiators

“…Since 2014, several applications have been found for these molecular photoswitches such as the development of light-responsive drug delivery systems [34,35], liquid crystals [36], or colorimetric sensors [37,38]. To the best of our knowledge, DASA have never been reported as polymerization photoinitiators, despite the fact their strong absorption in the visible region makes these dyes ideal candidates for such an application.…”

Light‐ and Chemical‐Stimuli‐Induced Isomerization of Donor−Acceptor Stenhouse Adducts

“…[29][30][31] More recently we reported a new derivative of the first generation DASAs based on a diamine donor (N,N,N'-trimethylethylenediamine). [32] Different to those previously reported DASAs, a double-cyclized piperazinium-cyclopentanone isomer has been isolated for the first time. This isomer is particularly stable and does not convert back to the linear form in the dark.…”

“…In this work, we designed and synthesized three new multistimuli-responsive DASAs (1-3, Scheme 1) bearing a pyridine pendant in the donor moiety. The use of pyridine instead of aliphatic amine [32] as the pendant gave rise to improved reversibility. They present intriguing isomerization upon light irradiation as well as chemical-stimuli, and the switching behaviors are dependent on the position of N atom in pyridine.…”