Tacticity is a crucial factor affecting the properties of synthetic polymer materials. Here, we introduce a type of chiral organic Brønsted acid catalyst, 1,1′-bi-2-naphthol-derived N,N′-bis(triflyl)phosphoramidimidates (PADIs), for the cationic polymerization of vinyl ethers, which enables the development of the first organocatalytic, highly stereoselective, cationic reversible addition−fragmentation chain-transfer (RAFT) polymerization of vinyl ethers with a trithiocarbonate chain-transfer agent. This metal-free RAFT process could afford isotactic poly(vinyl ethers) with high stereoselectivity, controllable molecular mass, and narrow dispersity at low catalyst loadings (as low as 200 ppm). Moreover, the trithiocarbonate chain-end allows for chain extension to synthesize diblock copolymers comprising an isotactic poly(vinyl ether) block, by a mechanistic switching from stereoselective cationic RAFT polymerization to visible-light-regulated cationic and radical RAFT polymerization.

Visible light-regulated metal-free polymerizations have attracted considerable attention for macromolecular syntheses in recent years. However, few organic photocatalysts show high efficiency and strict photocontrol in cationic polymerizations. Herein, we introduce monophosphonium-doped polycyclic arenes as an organic photocatalyst, which features the high tunability, broad redox window, long excited state lifetime, and excellent temporal control in the cationic reversible addition−fragmentation chain transfer polymerization of vinyl ethers. A correlation of the catalytic performance and the photophysical and electrochemical properties of photocatalysts is also discussed.

Fluorescence-based on-site and long-term sensing and bioimaging of biomarkers are highly desired for effective diagnosis. Aggregation-induced emission luminogens (AIEgens) with excited-state intramolecular proton transfer (ESIPT) characteristics have outstanding advantages in...

I 2 /dimethyl sulfoxide (DMSO)-mediated C−S, S−N, and C−N bond cross-coupling cyclization reaction for the synthesis of 5-acyl-1,2,3-thiadiazoles from enaminones, tosylhydrazine, and elemental sulfur has been developed under transition-metal-free conditions. This strategy is operationally simple, compatible with a wide range of functional groups, and provides the desired products in moderate to excellent yields.

A simple and efficient electrochemically induced thiocyanation of enaminones under undivided electrolytic conditions has been developed. With this protocol, various polyfunctionalized alkenes and chromones could be obtained in good to excellent yields using readily available KSCN as the thiocyanation reagent under catalyst-, oxidant-, and transition-metal-free conditions.