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The branched structures of dendronized polymers can provide good steric stabilization for metal nanoparticle catalysts. In this work, an amphiphilic dendronized copolymer containing hydrophilic branched triethylene glycol moieties and hydrophobic branched ferrocenyl moieties is designed and prepared by one-pot ring-opening metathesis polymerization, and is used as the stabilizer for metal (Au, Ag and Pd) nanoparticles. These metal nanoparticles (Au nanoparticles: 3.5 ± 3.0 nm; Ag nanoparticles: 7.2 ± 4.0 nm; Pd nanoparticles: 2.5 ± 1.0 nm) are found to be highly active in both the 4-nitrophenol reduction and Suzuki–Miyaura reactions. In the 4-nitrophenol reduction, Pd nanoparticles have the highest catalytic ability (TOF: 2060 h−1). In addition, Pd nanoparticles are also an efficient catalyst for Suzuki–Miyaura reactions (TOF: 1980 h−1) and possess good applicability for diverse substrates. The amphiphilic dendronized copolymer will open a new door for the development of efficient metal nanoparticle catalysts. [ABSTRACT FROM AUTHOR]

Metallopolymers with precise structures and particular properties have emerged as promising functional materials. The applications of metallopolymers depend on the unique characteristics of the metal centers (such as electronic, optical, magnetic, redox, etc.) and the superior mechanical and processing performances of classical polymers. Access to accurately design metallopolymers with well-defined structures and chemical compositions has enabled researchers to detailedly investigate their performances and a series of advanced applications. Along with the rapid development of modern synthetic chemistry and polymerization techniques, various functional metallopolymers have been synthesized largely and have shown many potential applications. Especially, controlled polymerizations, including ATRP, RAFT, ROMP, living anionic polymerization, and so on, are currently attracting considerable attention for the synthesis of well-defined metallopolymers. These polymerizations have become versatile and powerful synthetic tools, which enable the synthesis of new metallopolymers with accurately controlled molecular weight, relatively narrow molecular weight distribution, composition (block, graft, alternating gradient copolymers), and various functionalities. In this review, we highlight the most recent progress on the controlled synthesis of various well-defined metallopolymers. The review summarizes the recent progress on controlled polymerizations (such as ATRP, RAFT, ROMP, living anionic polymerization, etc.) for various well-defined metallopolymers, and these polymerizations enable the synthesis of novel metallopolymers with accurately controlled molecular weight, relatively narrow molecular weight distribution, composition (block, graft, alternating gradient copolymers), and diverse functionalities. [ABSTRACT FROM AUTHOR]

Gallol-functionalized polymers are highly desirable for their addressable functions in the fields of materials science, nanotechnology and biomedicine, owing to gallol's unique chemistry including excellent chelating properties to metals, easily oxidability and superior ability to bind proteins. Herein, we report the controlled synthesis of the first polynorbornene-based side-chain gallol-containing homopolymers and block copolymers with pendent triethylene glycol (TEG) moieties by the ring-opening metathesis polymerization (ROMP) using the 3rd generation Grubbs catalyst 1 as the initiator. We describe the direct synthetic route by the ROMP of a gallol-containing norbornene monomer, and the indirect approach via an acetoxyl protection/deprotection route. Among the tested metal ions of Fe 3+ , Mg 2+ , Cr 3+ and Al 3+ , Fe 3+ is the most effective metal ion to induce the gelation of the present gallol-containing polymers, and UV–visible spectroscopy indicates that bis-coordinated state dominates for the interaction between side-chain gallol groups and Fe 3+ ions in DMF. The gelation rate, interior structure, thermal and mechanical properties of the Fe 3+ -induced metallogels can be effectively tuned by changing the gallol/Fe 3+ molar ratio, polymeric molecular weight, and by introducing of organic TEG block. Furthermore, the oxidant-induced organogels were fabricated by adding the oxidant of NaIO 4 into the DMF solution of the gallol-containing polymers, and the gelation rate highly depends on the gallol/IO 4 − molar ratio and the introduction of TEG block. We are convinced that the effective synthesis of well-defined gallol-containing polymers, as illustrated by the present work, will pave the way for their functional applications as smart organogels, coatings, adhesives, capsules, etc. [ABSTRACT FROM AUTHOR]

Abstract We present the controlled synthesis of the polynorbornene-based well-defined block copolymer PNFc- b -PNAd side-chain containing ferrocene (Fc) and adamantane (Ad) units by the ring-opening metathesis polymerization using the 3rd generation Grubbs catalyst. A polycationic amphiphilic block copolymer PNFcium- b -PNAd was then fabricated by the stoichiometric oxidation of Fc into ferricinium (Fcium) cations, and its redox-controlled reversible self-assembly behavior in water was demonstrated by SEM and DLS with glutathione as reductant and FeCl 3 as oxidant. By using benzocaine (BA) as model cargo, the loading ability of the cationic micelles formed by PNFcium- b -PNAd was investigated and confirmed, and the reduction of Fcium could lead to the rapid release of loaded payloads. A new supramolecular copolymer PNFc- b -PNAd@β-CD was further prepared by simply mixing PNFc- b -PNAd and β-cyclodextrin (β-CD) with equimolar quantity to Ad units, in which host-guest interactions were mainly observed between β-CD and pendant Ad. Owing to the formation of hydrophilic inclusion complexes, PNFc- b -PNAd@β-CD possesses amphiphilic property and exhibits redox-controlled self-assembly behavior in water, too. The oxidation-triggered release of loaded-BA from the supramolecular micelles was observed in a slow and durable way. The present novel redox-responsive micelles provide innovative examples of rational design for stimuli-responsive carriers by using Fc-containing polymers. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

The development of novel polymer carriers, which have well-defined structures and desired conjugative abiltiy to therapeutic agents, is still an urgent requirement in the field of polymer–drug conjugates (PDCs) used for stimuli-responsive drug delivery systems. Herein, we present the controlled synthesis of a novel amphiphilic polynorbornene-based block copolymer, side-chain containing hydrophobic functionalizable benzaldehyde groups and hydrophilic dentritic triethylene glycol (TEG) moieties, by the ring-opening metathesis polymerization (ROMP) using the 3rd generation Grubbs catalyst 1 as the initiator. The obtained copolymer can self-assemble into spherical micelles with the average size of 84 nm in water, and its remarkable ability as the polymer carrier to fabricate PDCs was fully confirmed by the efficient covalently Schiff-base linking of its side-chain benzaldehyde groups to amino groups of model drugs including O-benzylhydroxylamine (BHA), 1-hexadecanamine, tryptophan and benzocaine. Notably, torispherical micelles with the average size of 90 nm were also obtained by the self-assembly of the formed polymer-BHA conjugate, and the pH-triggered release of BHA molecules from the micelles was observed at acidic environments (for example, pH 4.0 and 2.5). Therefore, the present polynorbornene block copolymer is expected to find potential applications in the stimuli-responsive drug delivery systems as a promising polymer carrier to form PDCs via acid-responsive Schiff-base linkage with amino-containing drugs such as doxorubicin, daunorubicin, epirubicin and pirarubicin. [ABSTRACT FROM AUTHOR]