Facile topological transformation of ABA triblock copolymers into multisite, single-chain-folding and branched multiblock copolymers via sequential click coupling and anthracene chemistry

Telechelic PtBA-b-PSt-b-PtBA copolymers were designed to achieve on-demand topological transformation into multisite, single-chain-folding and branched multiblock copolymers via click/click-like reactions.

Copolymers of ε-caprolactone and ε-caprolactam via polyesterification: towards sequence-controlled poly(ester amide)s

Alternating copolymer of ε-caprolactone and ε-caprolactam is synthesized through polyesterification. This efficient and straightforward strategy holds promising future for the synthesis of sequence-controlled poly(ester amide)s.

Synthesis of multisegmented block copolymer by Friedel–Crafts hydroxyalkylation polymerization

Friedel–Crafts (FC) polycondensation of 1,4-dimethoxybenzene with 4-substituted benzaldehyde species was used to prepare telechelic oligomers and high-molar-mass multisegmented block copolymers.

Alternating Sequence Control for Poly(ester amide)s by Organocatalyzed Ring-Opening Polymerization

Sequence-controlled polymerization is the forefront of polymer chemistry. Herein, the feasibility of sequence regulation by using organocatalyzed ring-opening polymerization (ROP) is demonstrated. In particular, ring expansion strategy is employed to synthesize pre-organized monomers 1 and 2. ROP is conducted by using 1,5,7-triazabicyclo[4.4.0]dec-5-ene and benzyl alcohol as the catalyst and initiator, respectively. Poly(ester amide)s (PEAs) P1-P3 comprising glycolic acid, lactic acid, and 7-aminoheptanoic acid units are obtained in high molecular weights and good yields. NMR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry results verify the microstructural integrity of P1 and P2. Differential scanning calorimetry results show that PEA without methyl branches is crystalline. Moreover, thermal stability, surface wettability, and degradation profiles of P1-P3 are also investigated.

Multicomponent spiropolymerization of diisocyanides, alkynes and carbon dioxide for constructing 1,6-dioxospiro[4,4]nonane-3,8-diene as structural units under one-pot catalyst-free conditions

A novel multicomponent spiropolymerization was developed by using diisocyanide, alkyne and CO₂, and 1,6-dioxospiro[4,4]nonane-3,8-diene was instantly formed.

Dual Sequence Control of Uniform Macromolecules through Consecutive Single Addition by Selective Passerini Reaction

The selective Passerini reactions of 4-formylbenzoic acid and 4-isocyanobenzoic acid with aliphatic isocyanides and aldehydes were utilized to synthesize sequence-defined uniform macromolecules. Our strategy does not involve any protecting groups or reactive group transformation steps and allows direct and consecutive propagation of sequence in each step. Introduction of diverse side groups by using different aliphatic components provided a range of sequence-defined uniform macromolecules in high yield and gram scale. The strategy also allows further Passerini self-coupling or cross-coupling of the formed sequences with other small molecules, affording polymers with up to 5098.3 Da and 20 side groups. Thus, this strategy will show promise for more efficient synthesis of new sequence-defined macromolecules.

Rational Design of Polymeric Nanoparticles with Tailorable Biomedical Functions for Cancer Therapy

Polymeric nanoparticles (NPs) play a key role in nanoscale formulations for bioimaging, cancer treatment, and theranostics. In this work, we designed and synthesized a series of hydrophobic polymers (P1-6) with different pendent groups via one-step multicomponent Passerini reaction. These polymers possessed similar molecular structures and various biomedical functions. Interestingly, they could self-assemble into stable NPs in aqueous media. All formed NPs were redox sensitive because of the existence of disulfide bonds in the backbone. The stability of NPs in aqueous media with or without glutathione was systematically evaluated and compared. The optical performance, including fluorescence resonance energy transfer, was characterized under different conditions for those polymers with fluorescent components. Importantly, all formed NPs showed good cytocompatibility toward HeLa cells and different biological functions, including drug loading and delivery, bioimaging with variable fluorescence, and photodynamic activity, as evidenced by experiments in vitro and in vivo. These results demonstrate the great potential of multicomponent reaction to customize versatile polymeric nanoparticles for biomedical applications.

Metal-Free Multicomponent Tandem Polymerizations of Alkynes, Amines, and Formaldehyde toward Structure- and Sequence-Controlled Luminescent Polyheterocycles

Sequence-controlled polymers, including biopolymers such as DNA, RNA, and proteins, have attracted much attention recently because of their sequence-dependent functionalities. The development of an efficient synthetic approach for non-natural sequence-controlled polymers is hence of great importance. Multicomponent polymerizations (MCPs) as a powerful and popular synthetic approach for functional polymers with great structural diversity have been demonstrated to be a promising tool for the synthesis of sequence-controlled polymers. In this work, we developed a facile metal-free one-pot multicomponent tandem polymerization (MCTP) of activated internal alkynes, aromatic diamines, and formaldehyde to successfully synthesize structural-regulated and sequence-controlled polyheterocycles with high molecular weights (up to 69 800 g/mol) in high yields (up to 99%). Through such MCTP, polymers with the in situ generated multisubstituted tetrahydropyrimidines or dihydropyrrolones in the backbone and inherent luminescence can be easily obtained with high atom economy and environmental benefit, which is inaccessible by other synthetic approaches.

Facile Synthesis of H2O2-Cleavable Poly(ester-amide)s by Passerini Multicomponent Polymerization

We report the straightforward synthesis of two types of H₂O₂-cleavable poly(ester-amide)s (P1 and P2) via the Passerini multicomponent polymerization (P-MCP) of 4-formylbenzeneboronic acid pinacol ester with 1,6-diisocyanohexane and 1,6-hexanedioic acid or a polyethylene glycol (PEG) dicarboxylic acid. The H₂O₂-cleavable phenylboronic acid ester was integrated into the polymer backbone by the in situ formed benzyl ester bond. GPC and ¹H NMR confirmed the complete H₂O₂-triggered degradation of these polymers in aqueous medium by a mechanism of sequential oxidation of phenylboronic acid ester and self-immolative elimination. Compared with the hydrophobic polymer P1, the PEG-based water-soluble polymer P2 degraded much faster even at a lower H₂O₂ concentration. Cytocompatible nanoparticles of polymer P1 loaded with fluorescent Nile red were fabricated, and controlled release of Nile red in response to H₂O₂ was achieved, thus, demonstrating the utility of these polymers as potential H₂O₂-responsive delivery vehicles.

Unique alternating peptide–peptoid copolymers from dipeptides via a Ugi reaction in water

Unprecedented alternating poly(peptide-alt-peptoid) copolymers are prepared in a single step from dipeptides, aldehydes and isocyanidesviaa Ugi reaction in water.

Addressing the mid-point of polymer chains for multiple functionalization purposes through sequential thiol–epoxy ‘click’ and esterification reactions

A synthetic strategy is devised for the preparation of mid-chain multifunctional polymers.

High-throughput polymer screening in microreactors: boosting the Passerini three component reaction

The Passerini three-component reaction (Passerini-3CR) has been studied via on-line microreactor/electrospray ionisation mass spectrometry (MRT/ESI-MS) reaction monitoring to demonstrate the high-throughput screening potential of microreactors for macromolecular design.

Controlling molecular weight and polymer architecture during the Passerini three component step-growth polymerization

A new approach to control the molecular weight and polymer architecture using the Passerini three-component step-growth polymerization is described.

Reduction-sensitive amphiphilic copolymers made via multi-component Passerini reaction for drug delivery

One-step synthesis of amphiphilic polymers containing disulfide bond within the hydrophobic backbone was demonstrated via multi-component Passerini reaction. The obtained polymer was self-assembled into micelles in aqueous solution. Curcumin (CUR), an effective and safe anticancer agent, which was limited by its water insolubility and poor bioavailability, was loaded into the micelles as a model drug. The nanoscale polymeric micelles were confirmed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Faster intracellular CUR release was observed by confocal laser scanning microscopy (CLSM) in the HeLa cells pretreated with GSH than in the unpretreated ones. Micelles also loaded with NH2-BODIPY which was almost non-fluorescent and gave strong enhanced fluorescence under acid conditions. The phenomenon of the stronger enhanced fluorescence in the pretreated HeLa cells showed further that the obtained polymer was reduction-sensitive. In vitro MTT assays showed that the micelles were biocompatible and CUR-loaded micelles had higher cellular proliferation inhibition in contrast to free CUR toward HeLa cells. These results highlight the potential of using multi-component Passerini reaction to make functional copolymers as smart nanocarriers for drug delivery.

Sequential Michael addition thiol–ene and radical-mediated thiol–ene reactions in one-pot produced sequence-ordered polymers

Sequential Michael addition-based thiol–ene and free radical mediated thiol–ene reactions for preparing sequence-ordered polymers are reported for the first time.

Enhanced reactivity of dendrons in the Passerini three-component reaction

An unexpected substituent effect that accelerates Passerini reactions in THF has enabled the synthesis of three generations of dendrimers.

Homopolymer bifunctionalization through sequential thiol–epoxy and esterification reactions: an optimization, quantification, and structural elucidation study

In this study, we probe various aspects of a post-polymerization double-modification strategy involving sequential thiol–epoxy and esterification reactions for the preparation of dual-functional homopolymers.

Dual side chain control in the synthesis of novel sequence-defined oligomers through the Ugi four-component reaction

The synthesis of sequence-defined oligomers by the iterative application of the modular Ugi four-component reaction (U-4CR) and the efficient thiol–ene addition reaction is described.

Combination of Orthogonal ABB and ABC Multicomponent Reactions toward Efficient Divergent Synthesis of Dendrimers with Structural Diversity

Synthesis of dendrimers has been directed toward process efficiency and structural diversity. We report a divergent approach to the preparation of dendrimers with both ABC and ABB branching structures from nonbranching monomers by combination of efficient orthogonal ABC Passerini multicomponent reaction (MCR) and ABB thiol-yne MCR. Two kinds of dendrimers were synthesized efficiently: (1) dendrimers with two generations in three steps and (2) dendrimers with two generations containing one kind of internal functional group and two kinds of surface functional groups in five steps. This new synthetic method offers an efficient access to dendrimers with structural diversity.

Precision polymers: a kinetic approach for functional poly(norbornenes)

Control over monomer sequence in the ring-opening metathesis polymerization of functional norbornenes is explored based on the difference in reactivity of endo and exo isomers.

Introducing the Ugi reaction into polymer chemistry as a green click reaction to prepare middle-functional block copolymers

The Ugi reaction has been utilized as a new click reaction to synthesize middle-functional copolymers.

A facile one pot strategy for the synthesis of well-defined polyacrylates from acrylic acid via RAFT polymerization

Linear and hyperbranched polyacrylates were successfully synthesized by the combination of in situ esterification of acrylic acid with halogenated compounds promoted by 1,1,3,3-tetramethylguanidine (TMG) and RAFT polymerization.

Synthesis of cross-linked polymers via multi-component Passerini reaction and their application as efficient photocatalysts

Cross-linked polymers containing Ru complexes synthesized via multi-component Passerini reaction were shown to be highly effective and recyclable heterogeneous photocatalysts.