N‐Acyl Dibenzazepine Chemistry as Versatile Approach for Photoreversible Thiol‐Ene Networks

Abstract

It is herein reported that a facile application of N‐acyl dibenzazepine (ADBA) photochemistry for preparing photoreversible ADBA based thiol‐ene networks. Crosslinking of the ADBA thiol‐ene networks is successfully achieved by UV induced dimerization of ADBA groups at wavelengths above 300 nm while a subsequent deep UV exposure (λ = 250 nm) results in a well‐defined cleavage of the crosslinks. The photochemical bonding and cleavage of the process has been determined and studied in detail by spectroscopic measurements.

Linear Cyclobutane-Containing Polymer Synthesis via [2 + 2] Photopolymerization in an Unconfined Environment under Visible Light

“…An interesting feature of the [2 + 2] cycloaddition is its reversibility, and it was reported that the cyclobutane ring can undergo decyclization when irradiated with light of appropriate wavelengths. − We checked the possible decyclization of this polymer under irradiation with an UV light source (λ max = 275 nm), and a clear decrease in viscosity was observed after the system was irradiated for 24 h. The depolymerization of P1 can be further confirmed by overlaying GPC traces (Figure D). After 72 h of irradiation, the M n of P1 was found to be reduced from 140 to 10.6 kDa, suggesting a certain degree of degradation happened.…”