Tetra-ortho-substituted, heteroaryl and cyclic azobenzenes have emerged as three key strategies on morphology design of photoswitch to diversify controllability. Cyclic azobenzene is of particular utilization in photo-energy conversion due to rigid and ring-strain structure. Despite the well-recognized diazocine, the photo-switching properties of seven-membered cyclic azobenzenes (diazepines) have yet been exploited. Herein, we report a family of dibenzo[b,f]-[1,4,5]chalcogenadiazepines (DBChDs) and their T-type photo-switching nature with tunable relaxation rate.Based on experiments together with DFT calculations, we found that an unsymmetric 2-bithiophenyl-dibenzo-[b,f][1,4,5]thiadiazepine exhibited an efficient response to 445 nm laser stimulation (quantum efficiency, Φ Z!E = 0.71) with millisecond relaxation half-life (t 1/2 = 40 ms). Photo-energy transduction efficiency was also exceptionally high with 29.1 % converted into ring-strain energy mainly loaded on azo π-bond.
A highly efficient dearomatization of 3-(2-isocyanoethyl)indoles with in situ generated nitrile imines has been developed though a nucleophilic/Friedel–Crafts/aza-Mannich type cascade and 1,3-dipolar cycloaddition reaction under catalyst-free and mild reaction conditions....
Cyclic azodicarbonyl derivatives, particularly 4phenyl-1,2,4-triazoline-3,5-dione (PTAD), commonly serve as arenophile, dienophile, enophile and electrophile. Perplexed by its instability in aqueous environment, there are few studies focused on the transient intermediate produced by hydrolysis of PTAD to achieve synthetic significance. Herein, we describe a "photo-click" method that involves nitrile imine (NI) from diarylsydnone to capture the diazenecarbonylphenyl-carbamic acid (DACPA) generated by water-promoted ring-opening of PTAD. DFT calculation reveal that H-bonding interactions between PTAD and water are vital to form DACPA which exhibited an umpolung effect during ligation by nature bond orbit (NBO) analysis. The ultra-fast ligation resulted in carbamoyl formazans, as a unique Z $ E photoswitchable linker on target molecules, including peptide and drugs, with excellent anti-fatigue performance. This strategy is showcased to construct highly functionalized carbamoyl formazans in situ for photo-pharmacology and material studies, which also expands the chemistry of PTAD in aqueous media.
We investigated the feasibility of creating cyclic azobenzene/azobenzene-based photoswitchable drugs that can fine-tune antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with light dependence. Furthermore, a...
Herein, a novel metal-free strategy for construction deep-blue emissive bicyclic triazoline has been developed via cycloaddition reaction (up to 134 M-1s-1) of 4-Phenyl-1,2,4-triazoline-3,5-dione (PTAD) with vinyl azides. Bicyclic triazoline frameworks...
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