Visible Light-ATRP Driven by Tris(2 pyridylmethyl)amine (TPMA) Impurities in the Open Air.

Atom transfer radical polymerization (ATRP) of oligo(ethylene oxide) monomethyl ether methacrylate (OEOMA500 ) in water was enabled using CuBr2 with tris(2 pyridylmethyl)amine (TPMA) as a ligand under blue or green-light irradiation without requiring any additional reagent, such as a photo-reductant, or the need for prior deoxygenation. Polymers with low dispersity (Đ = 1.18-1.25) were synthesized at high conversion (95%>) using TPMA from three different suppliers, while no polymerization occurred with TPMA synthesized and purified in our laboratory. Based on spectroscopic studies, it is proposed that TPMA impurities (i.e., imine and nitrone dipyridine), which absorb blue and green light, can act as photosensitive co-catalyst(s) in a light region where neither pure TPMA nor [(TPMA)CuBr]+ , absorb light. This article is protected by copyright. All rights reserved.