Monomer Controlled Switchable Copolymerization: A Feasible Route for the Functionalization of Poly(lactide)

Abstract

Switchable polymerization is an attractive strategy to enable the sequential selectivity of multi‐block polyesters. Besides, these well‐defined multi‐block polyesters could enable further modification for wider applications. Herein, based on the reversible insertion of CO2 by Salen‐MnIII, a new monomer controlled self‐switchable polymerization route was developed. Chemoselective ring opening copolymerization of O‐carboxyanhydrides (OCAs) and lactide (LA) was explored without cocatalyst. The sequential conversion of OCAs and LA into the polymer chain could form multi‐block polyesters. Based on this strategy, a series of multi‐block polyesters with different pendant groups were synthesized. Furthermore, by modifying the propargyl‐containing copolymers with quaternary ammonium groups, we have realized antibacterial functionalization of PLA. These results imply the potential application of this strategy for the fabrication of functional polymers for biomedical applications.

Electrochemically Controlled Switchable Copolymerization of Lactide, Carbon Dioxide, and Epoxides

“…Our group reported a Salen‐Co complex with different chemical valences showing high polymerization selectivity of ROP of LA and ROCOP of CO 2 and epoxides [26–28] . Furthermore, we also explored the excellent switching ability of the Salen‐Mn complex (between metal alkoxide salt and metal carbonate salt) in our recent work [8, 29] . Based on the characteristics of the two monometallic complexes and the cooperative effect of the heterometallic catalyst, the heterometallic complex Salen‐Co‐Mn was expected to possess a combined character of Salen‐Co and Salen‐Mn complexes.…”

“…[5] A feasible solution to this challenge may be provided by the emerging field of switchable polymerization, in which the reactivity and selectivity of a single catalytic species can be adjusted in situ by imposing external stimuli. [6][7][8] This strategy has been expanded rapidly, and examples that utilize a variety of different external stimuli, including thermal, [9] chemical, [10] optical, [11] redox [12] or mechanical stimuli [13] to modulate the inherent reactivity and selectivity of the polymerization system have been reported. Most previous studies used metal-based redox-switchable catalysts.…”

“…[26][27][28] Furthermore, we also explored the excellent switching ability of the Salen-Mn complex (between metal alkoxide salt and metal carbonate salt) in our recent work. [8,29] Based on the characteristics of the two monometallic complexes and the cooperative effect of the heterometallic catalyst, the heterometallic complex Salen-Co-Mn was expected to possess a combined character of Salen-Co and Salen-Mn complexes. Therefore, an electrochemically controlled switchable copolymerization system is developed, in which the ROP of LA is active and the ROCOP of CO 2 and epoxide is dormant when the heteronuclear catalysts are in the reduced state.…”

Dual Reactive Oxygen Species Generator Independent of Light and Oxygen for Tumor Imaging and Catalytic Therapy

“…To realize the effective loading of trivalent manganese, we first synthesized the salen ligand by an aldimine condensation reaction between ethylenediamine (EDA) and salicylaldehyde. [17][18][19][20] Subsequently, the structure of salen was characterized by 1 H NMR (Figure S1). In the 1 H NMR spectrum, the hydrogen atom peaks at 13.39, 8.59, and 7.51-6.80 ppm were allocated to the exposure of salicylaldehyde.…”

Controllable Disulfide Exchange Polymerization of Polyguanidine for Effective Biomedical Applications by Thiol‐Mediated Uptake

“…), which may affect the biological activities of biomolecules. [1a, 6g] For example, biodegradable poly(lactide) was performed with HCl/dioxane; [8] a thioredoxin reductase drug delivery system was proposed by using tetrahydrofuran under 50 °C; [9] and fluorinated ɛ-Poly-L-lysine for gene transfection was achieved by using methanol for 48 h. [10] Disulfide bonds become almost ubiquitous in polymeric gene delivery carriers due to their minimal cytotoxicity and cytosolic degradation triggered by endogenous glutathione (GSH) in tumor cells. [6] The development of a simple, efficient, and safe synthetic procedure for bioreducible disulfide polymers is of much importance to biomacromolecule delivery systems.…”