Investigation On Multicomponent Polymerization Through Metal Carbene Intermediate

Polymer materials have become one of the indispensable materials in modern life.Polymer chemistry mainly studies the molecular design,synthesis,reaction,and modification of polymer compounds,which is the basis of polymer science.It is one of the critical methods to expand the polymer polymerization system by developing new polymer reactions through learning from organic synthesis reactions.As organic intermediates with active properties,metal carbenes have been increasingly used in polymer chemistry in recent years.The polymerization reaction involving metal carbene is mainly C1 polymerization using diazoacetate as the monomer.However,because the metal carbene monomer is unstable and the synthesis steps are complicated,there are few studies on metal carbene in other polymerization modes.Therefore,the development of a polymerization system more suitable for metal carbene participation is the key to expanding the application of metal carbene in polymerization.Multicomponent polymerization(MCP)refers to a new type of polymerization in which three or more monomers are directly reacted in a one-pot reaction to form polymers,and the resulting polymers contain structural fragments of all monomers.Multicomponent polymerization has the advantages of high atom economy,step economy,convenient product structure control,and efficient construction of polymer structures containing complex structures.With these advantages,the multicomponent polymerization mode of carbene-involved polymerization is expected to be efficient,avoiding the use of unstable and complicated prepared carbene precursors.First,we used dialkyne,dinucleophile,and Ts N₃ for multicomponent polymerization to synthesize polysulfonamides under bimetallic Cu(I)/Rh(II)relay catalysis.This bimetallic Cu(I)/Rh(II)relay catalyzed multicomponent polymerization proceeds through a tandem Cu-catalyzed azide-alkyne cycloaddition(Cu AAC),ring-opening,and Rh(II)-bound imino carbene insertion process.The synthesized polysulfonamides showed good thermal properties.The polysulfonamides performed large Stokes shifts and emission color,which can be adjusted from blue to yellow.The sulfonamide groups on the synthesized polysulfonamides were further used as the initiating sites for the ring-opening polymerization of N-sulfonal aziridines to generate comb-shaped copolymers.Then,we report the use of readily available alkynes,azides,and aryl nitriles for multicomponent polymerization to synthesize imidazole-based conjugated polymers under bimetallic Cu(I)/Rh(II)relay catalysis.This multicomponent polymerization proceeds through a tandem Cu-catalyzed azide-alkyne cycloaddition(Cu AAC),ring-opening,and transannulation process.The polymerization system is widely applicable to various aromatic diynes,diazides,and dinitriles and can prepare functional conjugated polyimidazoles with tunable fluorescence color and tunable band gap.This bimetallic relay-catalyzed multicomponent polymerization not only has a high yield and high atom economy but also expands the application of metal carbene in polymer synthesis and provides a novel and efficient method for the construction of conjugated functional polymers.