Synthesis of Unimolecular Micelles with Incorporated Hyperbranched Boltorn H30 Polyester modified with Hyperbranched Helical Poly(phenyl isocyanide) Chains and their Enantioselective Crystallization Performance

Abstract

Here, the fabrication of unimolecular micelles functionalized with helical polymeric chains as a chiral nucleating agent in enantioselective crystallization is reported. Starting from a fractionated hyperbranched polyester (Boltorn H30), the ring-opening polymerization of l-lactic acid (LLA) and subsequent terminal-group modification affords the alkyne-Pd(II)-anchored hyperbranched macroinitiator (H30-PLLA-Pd). By taking advantage of a Pd(II)-catalyzed living polymerization of chiral pendant modified l- or d-phenyl isocyanide (PI) monomers, well-defined chiral unimolecular micelles (H30-PLLA-PPI) grafted with radiating helical PPI coronas of one predominant screw sense are obtained. The resultant chiral materials demonstrate excellent application in the enantioselective crystallization of racemic threonine in water, and a 92% enantiomeric excess value of the residual solution is obtained. It is believed this present proof of concept and methodology are facile and powerful for preparing novel and versatile chiral materials with different topological structures, not only applicable to PPI but also to other types of polymers.

Semiflexible polymer scaffolds: an overview of conjugation strategies

“…225 This approach enables coupling of the polymer scaffold to a variety of substituents such as dyes or other polymers to generate (block) copolymers. 222,226,227 While the introduction of a handle via initiator modification is an elegant functionalization strategy, its applications are restricted, analogous to electrochemical coupling and ROP initiator modification mentioned earlier.…”

Amphiphilic hyperbranched polymers: synthesis, characterization and self-assembly performance

“…Hyperbranched polymers are drawing more and more attention especially in the fields of self-assembly owing to their specific size, shape and properties. Many impressive supermolecucular aggregates at all scales and dimensions have been obtained [14][15][16], such as unimolecular micelles, polymer vesicles, composite vesicles and macroscopic tubes. Further research about amphiphilic hyperbranched polymers have been demonstrated unique advantages in supramolecular self-assembly behaviors, including special properties, unique self-assembly mechanisms and functionalization processes.…”

Facile Synthesis of Helical Rod–Coil Block Polymers by the Combination of ATRP and Pd(II)‐Initiated Isocyanides Polymerizations

“…Recently, our group reported a family of alkyne‐Pd(II) complexes which can initiate the living polymerization of isocyanide monomers and lead to the formation of stereoregular helical polyisocyanides with controlled molar masses ( M n s) and narrow molar mass distributions ( M w / M n s). Moreover, these Pd(II) complexes are efficient catalyst with tolerance to most organic solvents and easy to be synthesized …”