Metal-promoted C1 polymerizations

C1 polymerizations provide a means to grow polymer chains one carbon atom at a time. Such methodology enables the synthesis of persubstituted polymers that are challenging to prepare using conventional C2 polymerizations, which typically utilize alkene-based monomers and thus grow polymer chains two carbons at a time. Persubstituted polymers feature higher densities of pendant functional groups and, as such, offer the potential to exhibit enhanced physical and/or chemical properties over their monosubstituted C2 polymer analogues. This review summarizes the various metals that have been used to promote Cl polymerizations in a catalytic or stoichiometric manner. Discussions are stratified according to the monomers used, which are formally carbenes or carbynes and typically employed as their respective ylides, isocyanides, diazo compounds, or geminal di- or trihalides. Emphasis is placed on the scope of the polymerization chemistry, underlying mechanisms, and outstanding opportunities in the field. (C) 2018 Elsevier B.V. All rights reserved.