ATRP is catalytic process using a metal complex, in which the transition metal Mt can exist in two different oxidation states. The lower oxidation state metal complex Mtz/L (L is a ligand) reacts with the ATRP initiator (alkyl halide RX) to yield a radical R• and the corresponding higher oxidation state metal complex with a coordinated halide anion X-Mtz+1/L, in a process termed activation