Fast Living Polymerization and Helix-Sense-Selective Polymerization of Diazoacetates Using Air-Stable Palladium(II) Catalysts

Abstract

In this work, air-stable palladium(II) catalysts bearing bidentate phosphine ligands were designed and prepared, which could initiate fast and living polymerizations of various diazoacetate monomers under mild conditions. The polymerization afforded the desired polymers in high yields with controlled molecular weights (M n s) and narrow molecular weight distributions (M w /M n s). The M n s of the isolated polymers were linearly correlated to the initial feed ratios of monomer to catalyst, confirming the living/controlled manner of the polymerizations. The M n also increased linearly with the monomer conversion, and all of the isolated polymers showed narrow M w /M n s. The polymerization was relatively fast and could be accomplished within several minutes. Such fast living polymerization method can be applied to a wide range of diazoacetate monomers in various organic solvents at room temperature in air. Taking advantage of the living nature, we facilely prepared a series of block copolymers through chain extension reactions. The amphiphilic block copolymers synthesized by this method exhibited interesting self-assembly properties. Moreover, polymerization of achiral bulky diazoacetate by Pd(II) catalysts bearing a chiral bidentate phosphine ligand leads to the formation of polymers with high optical activity due to the formation of the predominantly one-handed helix of the main chain. The helix sense of the polymers was determined by the chirality of the Pd(II) catalysts.

Revisiting the Polymerization of Diphenylacetylenes with Tungsten(VI) Chloride and Tetraphenyltin: An Alternative Mechanism by a Metathesis Catalytic System

“…Our study serves as a starting point to develop substantially improved catalytic systems for polymerization of various diphenylacetylenes, which are essential for research and development of novel functional materials based on poly(diphenylacetylene)s . More generally, we anticipate that an discovery of the alternative pathway by ill‐defined metathesis catalysts will promote the development of novel well‐defined tungsten catalysts in organometallic and synthetic chemistry.…”

Chiral Graphene Hybrid Materials: Structures, Properties, and Chiral Applications

“…These strategies include using chiral catalyst, chiral monomer‐achiral monomer copolymerization, chiral field, and chiral postinduction. [ 186,187 ] In the study (Figure 11), [ 175 ] achiral acetylenic monomer (M B ) underwent HSSP with l ‐ascorbic acid ( l ‐AA) as chiral source. Indeed, l ‐AA is widely used as reducing agent for the reduction of GO.…”

Helicity‐ and Molecular‐Weight‐Driven Self‐Sorting and Assembly of Helical Polymers towards Two‐Dimensional Smectic Architectures and Selectively Adhesive Gels

“…To the best of our knowledge, helicity‐driven self‐recognition in synthetic assemblies like those in DNA and proteins is seldom reported. Possible reasons are that single‐handed helical polymers without any chiral moieties, in which the chirality solely comes from the helix‐sense, are very rare [30–33] . Moreover, the reported helical polymers usually have no specific recognition units or the units are far from the chiral moieties.…”

“…Possible reasons are that single-handed helical polymers without any chiral moieties,i nw hich the chirality solely comes from the helix-sense,are very rare. [30][31][32][33] Moreover,t he reported helical polymers usually have no specific recognition units or the units are far from the chiral moieties.T he strong intermolecular interactions and chain entanglement between long polymer chains usually lead to stereocomplexes of chiral polymers. [34] However,h elicitydriven self-sorting is particularly intriguing because it may be closely related to the origin of homochirality in Nature,a nd also attractive to the research fields of chirality recognition, enantiomer separation, chiral self-assembly and so on.…”