Benzoyl Phenyltelluride as Highly Reactive Visible-Light TERP-Reagent for Controlled Radical Polymerization

Benzoyl phenyltelluride (BPT) is a highly reactive TERP-reagent for visible-light-induced (400-500 nm) controlled radical polymerization. The compound can be easily prepared in one step from diphenyl ditelluride and benzoyl chloride. It shows a strong absorption at 407 nm that tails out to 473 rim and provides PDIs (1.2 to 1.3) among the lowest reported in literature for photoiniferters in general, to which our compound was compared. PDIs obtained with BPT are much lower than those for benzyl dithiocarbamte (BDC) (1.7 to 1.8), which was used as a reference compound. Choice of BDC as reference is based on its property as UV-photoiniferter and on a similar initiation/control mechanism. However, BDC does not allow living radical polymerization under visible light. The newly discovered compound BPT provides best results with acrylamides and acrylates. Photoinitiation with styrene was ineffective, and reaction with methacrylates is not considered living.