Graeme Moad - Universal (Swithchable) RAFT Agents

Version 1

      Publication Details (including relevant citation   information):

      Massimo Benaglia, John Chiefari, Yen K. Chong, Graeme Moad, Ezio   Rizzardo,San H. Thang; JACS, 2009, 131(20), 6914–6915

      Abstract:

      The polymerization of most monomers polymerizable by radical   polymerization can be controlled by the RAFT process.    However, it is usually required that the RAFT agent be selected   according to the types of monomer being polymerized.  Thus,   RAFT agents (dithioesters, trithiocarbonates) suitable for   controlling polymerization of the ‘more activated’ monomers (MAM,   e.g. styrene, acrylates, methacrylates, etc.) tend to inhibit   polymerizations of ‘less activated’ monomers (LAM, e.g. vinyl   acetate, N-vinylpyrrolidone, etc.).  Similarly RAFT agents   suitable for polymerizations of ‘less activated’ monomers   (xanthates, certain dithiocarbamates) tend to give little or poor   control over polymerizations of MAMs.   We now report a   new class of “switchable” RAFT agents.  Thus,   N-(4-pyridinyl)-N-methyldithiocarbamates provide excellent   control over polymerization of LAMs and after addition of one   equivalent of a protic or Lewis acid they become effective in   controlling polymerization of MAMs allowing the synthesis of   polyMAM-block-polyLAM with narrow molecular weight distributions.

      Address (URL): http://pubs.acs.org/doi/abs/10.1021/ja901955n