Access to Heterogeneous Atom-Transfer Radical Polymerization (ATRP) Catalysts Based on Dipyridylamine and Terpyridine via Ring-Opening Metathesis Polymerization (ROMP)



A series of dipyridylamine and terpyridine derivatives, norborn-2-ene-5-di(pyrid-2-yl)carbamide (1), 4′-(norborn-2-ene-5-ylmethyleneoxy)terpyridine (2), di-(pyrid-2-yl)acetamide (3) and bis(4′-(norborn-2-ene-5-ylmethyleneoxy)-2,2′:6′,2″-terpyridine)iron(II) hexafluorophosphate (4) have been synthesized. Linear homopolymers, poly-1 and poly-2, as well as grafted and coated silica- and PS-DVB-based polymer supports have been prepared therefrom via ring-opening metathesis polymerization (ROMP). Monomer 3, poly-1, poly-2 have been loaded with Cu (I), Cu (II), Fe (II) as well as Hg (II) salts, respectively. These metal complexes as well as metal loaded supports based on compounds 1, 2 and 4 have subsequently been used for homogeneous and heterogeneous atom-transfer radical polymerization (ATRP) of styrene. Systems based on poly-2 coated silica loaded with Cu (I) were found to work best. Under optimum conditions, polystyrene was obtained in 30% yield with polydispersity indices < 1.6 within 2 h and with a remaining metal content in the ng/g (ppb)-range.