Co(Ⅱ)-catalyzed Multicomponent Polymerization Of Isocyanide Monomers

Isocyanides are kinds of isoelectronic species with special carbon-nitrogen triple bond,which are chemically active and can take part in plenty of reactions,such as Passerini threecomponent reactions and Ugi four-component reactions.Isocyanides are also considered as essential monomers for the synthesis of products that are usable in agriculture and pharmacology.Multicomponent reactions and multicomponent polymerizations all enjoy the advantages of high reaction efficiency,mild reaction conditions,atom economy and easy operations,etc.However,most of the isocyanides suffer from pungent odour,which restrict their applications in different aspects.Thus,it is quite urgent to synthesize bis-isocyanides with no/small pungent odour,which could be utilized in establishing new multicomponent polymerizations.In this thesis we developed two efficient isocyanide-based multicomponent polymerizations.The Co(II)-catalyzed polymerization of bis-isocyanides,bis-sulfonyl azides and alcohols polymerization could readily generate polyisoureas with high molecular weights in high yields.The resultant polymers possess optical transparency and good thermal stability.Thanks to their good solubility,the resultant polymers can be fabricated into ribbon-like nanofiber through electrospunning.Moreover,the polymer containing tetraphenylethylene moieties exhibits distinct aggregation-induced emission effect and could be used in explosive detection with excellent sensitivity.Furthermore,when changing alcohols to amines,another multicomponent polymerization was developed and polyguanidines with high molecular weight were obtained in high yields.Similar to guanidine compounds our resultant polyguanidines could also show excellent antibacterial abilities towards gram-positive bacterium(particularly towards staphylococcus aureus),owing to the electrostatic interactions between polyguanidines and bacteira membranes.Meanwhile the low cell vialbility endow polyguanidine possibility to be applied into antiseptic dressing industry.Introuducing tetraphenylethylene moieties into polyguanidine,makes it exhibit green fluorescent,which could also be used in bacteria-imaging.