Dope new organocatalysts for ATRP

Radical Fluorosulfonyl Heteroarylation of Unactivated Alkenes with Quinoxalin-2(1H)-ones and Related N-Heterocycles

The incorporation of sulfonyl fluoride groups into molecules has been proved effective to enhance their biological activities or introduce new functions. Herein, we report a transition-metal-free and visible-light-mediated radical 1-fluorosulfonyl-2-heteroarylation of alkenes, which could allow access to a series of SO₂F-containing quinoxalin-2(1H)-ones, which are a critical structural motif widely present in a number of biologically active molecules. Further application of the method to the modification of other heterocycles and drug molecules as well as ligation chemistry via SuFEx click reactions is also demonstrated.

Monophosphoniums as Effective Photoredox Organocatalysts for Visible Light-Regulated Cationic 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.

Organocatalytic cationic degenerate chain transfer polymerization of vinyl ethers with excellent temporal control

A photo-controlled cationic degenerate chain transfer polymerization of vinyl ethers has been developed by using a bisphosphonium organophotocatalyst.

High-stability NIR-II fluorescence polymer synthesized by atom transfer radical polymerization for application in high-resolution NIR-II imaging

Near-infrared II (NIR-II, 1000-1700 nm) fluorescent imaging (FI) has been reported to achieve optical images with higher resolution and deeper penetration. Among the organic NIR-II small molecules, donor-acceptor-donor (D-A-D) type fluorescent agents have shown superior photophysical and biocompatible properties for FI applications but have ongoing limitations, such as the difficulty in further modifying them with drug-carrying functional groups or prodrugs. In this work, three D-A-D type NIR-II fluorophores with electron acceptors of 4,8-bis(5-bromo-4-(2-octyldodecyl)thiophen-2-yl)-1H,3H-benzo[1,2-c:4,5-c']bis([1,2,5]thiadiazole) (BBT), 6,7-bis(4-(hexyloxy)phenyl)-4,9-di(thiophen-2-yl)-[1,2,5]thiadiazolo[3,4-g]quinoxaline (TTQ) and 4,6-bis(5-bromo-2-thienyl)thieno[3,4-c][1,2,5]thiadiazole (TTDT) have been successfully prepared. Their optical and imaging properties and stability were investigated via theoretical and experimental studies. The results demonstrated that TTDT-SF exhibited good NIR-II imaging ability. Importantly, TTDT-SF showed outstanding stability in an alkaline and redox environment. Subsequently, a stable atom transfer radical polymerization (ATRP) initiator, based on TTDT and its derivative water-soluble fluorescent polymer TTDT-TF-POEGMA, synthesized through ATRP, was successfully fabricated. It was demonstrated that TTDT-TF-POEGMA exhibited excellent fluorescence ability, great water solubility, effective light stability and great potential in tumor FI and image-guided surgery. In a word, this work has developed a new stable initiator with NIR-II fluorescent properties, which provides a platform for the development of water-soluble and multifunctional NIR-II fluorescent polymers for a broad range of applications.