Application of a ferrocene-chelating heteroscorpionate ligand in nickel mediated radical polymerization



A nickel bromide complex supported by a non-innocent ferrocene-chelating heteroscorpionate ligand, [(fc(PPh2)(BH(3,5-Me2pz)2)NiBr] ((fcP,B)NiBr, fc = 1,1’-ferrocenediyl, pz = pyrazole), was synthesized and characterized. The compound can be readily oxidized according to UV-vis and 1H NMR spectroscopy. The catalytic activity of the compound’s different oxidation states in the polymerization of vinyl monomers was explored. AB and ABA-type block copolymers were made from styrene and p-chlorostyrene, offering an example of orthogonal redox control in radical polymerization.