One-step synthesis of sequence-controlled multiblock polymers with up to 11 segments from monomer mixture

Switchable polymerization holds considerable potential for the synthesis of highly sequence-controlled multiblock. To date, this method has been limited to three-component systems, which enables the straightforward synthesis of multiblock polymers with less than five blocks. Herein, we report a self-switchable polymerization enabled by simple alkali metal carboxylate catalysts that directly polymerize six-component mixtures into multiblock polymers consisting of up to 11 blocks. Without an external trigger, the catalyst polymerization spontaneously connects five catalytic cycles in an orderly manner, involving four anhydride/epoxide ring-opening copolymerizations and one L-lactide ring-opening polymerization, creating a one-step synthetic pathway. Following this autotandem catalysis, reasonable combinations of different catalytic cycles allow the direct preparation of diverse, sequence-controlled, multiblock copolymers even containing various hyperbranched architectures. This method shows considerable promise in the synthesis of sequentially and architecturally complex polymers, with high monomer sequence control that provides the potential for designing materials.

Star-like poly(peptoid)s with selective antibacterial activity

We developed new macromolecular engineering approaches enabling the preparation of star-like polypeptoids by ring-opening polymerization. Parallely to the evaluation of their cytotoxicity of the HepG2 human cell line, their screening...

N-heterocyclic carbene iron complexes catalyze the ring-opening polymerization of lactide

Poly(lactic acid), PLA, which holds great promises as a biodegradable substitute of fossil resource-derived polyolefins, is industrially produced by the ring-opening polymerization of lactide using a potentially harmful tin catalyst....

Cationic ring-opening polymerization of a five membered cyclic dithiocarbonate having a tertiary amine moiety

A dibenzylamine derived cyclic dithiocarbonate (1) undergoes ring-opening polymerization due to the greater reactivity of exocyclic sulfur compared to the tertiary amine with methyl triflate.

Poly(ʟ-lactide)s with Tetraphenylethylene: Role of Polymer Chain Packing on Aggregation-Induced Emission Behavior of Tetraphenylethylene

Development of biocompatible and biodegradable fluorescent polymers and understanding their fluorescent characteristics are highly desirable. In this work, we synthesized one-armed, two-armed and four-armed poly(ʟ-lactide)s by ring-opening polymerization of ʟ-lactide...

Microwave-assisted in situ ring-opening polymerization of ε-caprolactone in the presence of modified halloysite nanotubes loaded with stannous chloride

For the composite catalyst, there existed synergetic catalytic effect between the hydroxyl groups and the metal center. All chain growth simultaneously proceeded between the layers or on the surface of HNTs, conducting the in situ ROP.

Enhanced Anticancer Efficacy of Chemotherapy by Amphiphilic Y-Shaped Polypeptide Micelles

Although the treatment modalities of cancers are developing rapidly, chemotherapy is still the primary treatment strategy for most solid cancers. The progress in nanotechnology provides an opportunity to upregulate the tumor suppression efficacy and decreases the systemic toxicities. As a promising nanoplatform, the polymer micelles are fascinating nanocarriers for the encapsulation and delivery of chemotherapeutic agents. The chemical and physical properties of amphiphilic co-polymers could significantly regulate the performances of the micellar self-assembly and affect the behaviors of controlled release of drugs. Herein, two amphiphilic Y-shaped polypeptides are prepared by the ring-opening polymerization of cyclic monomer l-leucine N-carboxyanhydride (l-Leu NCA) initiated by a dual-amino-ended macroinitiator poly(ethylene glycol) [mPEG-(NH2)2]. The block co-polypeptides with PLeu8 and PLeu16 segments could form spontaneously into micelles in an aqueous solution with hydrodynamic radii of 80.0 ± 6.0 and 69.1 ± 4.8 nm, respectively. The developed doxorubicin (DOX)-loaded micelles could release the payload in a sustained pattern and inhibit the growth of xenografted human HepG2 hepatocellular carcinoma with decreased systemic toxicity. The results demonstrated the great potential of polypeptide micellar formulations in cancer therapy clinically.

Ring-Opening Polymerization of ε-Caprolactone and Styrene Oxide–CO2 Coupling Reactions Catalyzed by Chelated Dehydroacetic Acid–Imine Aluminum Complexes

A series of chelated dehydroacetic acid–imine-based ligands L1H~L4H was synthesized by reacting dehydroacetic acid with 2-t-butylaniline, (S)-1-phenyl-ethylamine, 4-methoxylbenzylamine, and 2-(aminoethyl)pyridine, respectively, in moderate yields. Ligands L1H~L4H reacted with AlMe3 in toluene to afford corresponding compounds AlMe2L1 (1), AlMe2L2 (2), AlMe2L3 (3), and AlMe2L4 (4). All the ligands and aluminum compounds were characterized by IR spectra, 1H and 13C NMR spectroscopy. Additionally, the ligands L1H~L4H and corresponding aluminum derivatives 1, 3, and 4 were characterized by single-crystal X-ray diffractometry. The catalytic activities using these aluminum compounds as catalysts for the ε-caprolactone ring-opening polymerization (ROP) and styrene oxide-CO2 coupling reactions were studied. The results show that increases in the reaction temperature and selective solvent intensify the conversions of ε-caprolactone to polycaprolactone. Regarding the coupling reactions of styrene oxide and CO2, the conversion rate is over 90% for a period of 12 h at 90 °C. This strategy dispenses the origination of cyclic styrene carbonates, which is an appealing concern because of the transformation of CO2 into an inexpensive, renewable and easy excess carbon feedstock.