64617-98-7Relevant academic research and scientific papers
Controlling Polymer Composition in Organocatalyzed Photoredox Radical Ring-Opening Polymerization of Vinylcyclopropanes
Chen, Dian-Feng,Boyle, Bret M.,McCarthy, Blaine G.,Lim, Chern-Hooi,Miyake, Garret M.
, p. 13268 - 13277 (2019)
Although radical polymerizations are among the most prevalent methodologies for the synthesis of polymers with diverse compositions and properties, the intrinsic reactivity and selectivity of radical addition challenge the ability to impart control over the polymerization propagation and produce polymers with defined microstructure. Vinylcyclopropanes (VCPs) can be polymerized through radical ring-opening polymerization to produce polymers possessing linear (l) or cyclic (c) repeat units, providing the opportunity to control polymer structure and modify the polymer properties. Herein, we report the first organocatalyzed photoredox radical ring-opening polymerization of a variety of functionalized VCP monomers, where high monomer conversions and spatial and temporal control were achieved to produce poly(VCPs) with predictable molecular weight and low dispersity. Through manipulating polymerization concentration and temperature, tunable l or c content was realized, allowing further investigation of thermal and viscoelastic materials properties associated with these two distinct compositions. Unexpectedly, the photoredox catalysis enables a postpolymerization modification that converts l content into the c content. Combined experimental and computational studies suggested an intramolecular radical cyclization pathway, where cyclopentane and cyclohexane repeat units are likely formed.
One-Pot synthesis of 5-Alkylthio-3H-1,2-dithiole-3-thiones: Advantages and scopes
Aimar,De Rossi
, p. 1749 - 1755 (2007/10/03)
The reaction of dialkyl malonate esters with P2S5/S8 in boiling xylene in the presence of 2-mercaptobenzothiazole/ZnO as catalyst produces 5-alkylthio-3H-1,2-dithiole-3-thiones as major identifiable product. Moderate yields were obtained with malonate esters of primary alcohols. The reaction fails with malonate esters of secondary alcohols. Regarding the substituent in position two, dialkyl malonates with groups such as CH3, Ph, CH2Ph, OCH3 and Cl afford the corresponding 4-substituted derivatives whereas with Br and NO2 do not give the expected products. Some mechanistic evidences are described.
