Recent progress of magnetic nanomaterials from cobalt-containing organometallic polymer precursors

This review summarizes the recent progress in the syntheses and materials applications of Co-containing organometallic polymers, and mainly focuses on the preparation of magnetic nanostructures from Co-containing organometallic polymer precursors.

Polymerization-Induced Self-Assembly of Metallo-Polyelectrolyte Block Copolymers

Cobaltocenium-containing polyelectrolyte block copolymer nanoparticles were prepared via polymerization-induced self-assembly (PISA) using aqueous dispersion RAFT polymerization. The cationic steric stabilizer was a macromolecular chain-transfer agent (macro-CTA) based on poly (2-cobaltocenium amidoethyl methacrylate chloride) (PCoAEMACl), and the core-forming block was poly(2-hydroxypropyl methacrylate) (PHPMA). Stable cationic spherical nanoparticles were formed in aqueous solution with low dispersity without adding any salts. The chain extension of macro-CTA with HPMA was efficient and fast. The effects of block copolymer compositions, solid content, charge density, and addition of salts were studied. It was found that the degree of polymerization of both the stabilizer PCoAEMACl and the core-forming PHPMA had a strong influence on the size of nanoparticles.

Synthesis and characterization of metal-rich phosphonium polyelectrolytes and their use as precursors to nanomaterials

Upon efficient quaternization and salt metathesis of stable triethyl ferrocene/ruthenocene phosphines, styrene-based phosphonium triflate monomers with four different stoichiometric ratios of Fe/Ru were synthesized. Free-radical polymerization of the monomers afforded four polyelectrolytes (M_n: 38 650-69 100 g mol^-1, Đ: 3.16-4.10) that retained many of the spectroscopic and electrochemical properties of the ferrocene/ruthenocene units. TGA studies demonstrated the thermal stability (onset of decomposition: ∼310 °C) and high char yields (33-54% at 1000 °C) of the polyelectrolytes. Pyrolysis in N₂/H₂ (95/5) (film thickness of ∼6 μm, 1000 °C, 3 h) yielded crystalline, mixed-phase nanomaterials containing iron, ruthenium, and phosphorus with compositions influenced by the structure of the parent polyelectrolytes.

Metal-containing polymers bearing pendant nickel(ii) complexes of Goedken's macrocycle

The design, synthesis, and characterization of polymers bearing pendant nickel(ii) complexes of Goedken's macrocycle are described.

Metallocene-Containing Homopolymers and Heterobimetallic Block Copolymers via Photoinduced RAFT Polymerization

We report the synthesis of cationic cobaltocenium and neutral ferrocene containing homopolymers mediated by photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization with a photocatalyst fac-[Ir(ppy)3]. The homopolymers were further used as macromolecular chain transfer agents to synthesize diblock copolymers via chain extension. Controlled/"living" feature of photoinduced RAFT polymerization was confirmed by kinetic studies even without prior deoxygenation. A light switch between ON and OFF provided a spatiotemporal control of polymerization.

Metal-containing and related polymers for biomedical applications

A survey of the most recent progress in the biomedical applications of metal-containing polymers is given. Due to the unique optical, electrochemical, and magnetic properties, at least 30 different metal elements, most of them transition metals, are introduced into polymeric frameworks for interactions with biology-relevant substrates via various means. Inspired by the advance of metal-containing small molecular drugs and promoted by the great progress in polymer chemistry, metal-containing polymers have gained momentum during recent decades. According to their different applications, this review summarizes the following biomedical applications: (1) metal-containing polymers as drug delivery vehicles; (2) metal-containing polymeric drugs and biocides, including antimicrobial and antiviral agents, anticancer drugs, photodynamic therapy agents, radiotherapy agents and biocides; (3) metal-containing polymers as biosensors, and (4) metal-containing polymers in bioimaging.

Recent advances in metathesis-derived polymers containing transition metals in the side chain

This account critically surveys the field of side-chain transition metal-containing polymers as prepared by controlled living ring-opening metathesis polymerization (ROMP) of the respective metal-incorporating monomers. Ferrocene- and other metallocene-modified polymers, macromolecules including metal-carbonyl complexes, polymers tethering early or late transition metal complexes, etc. are herein discussed. Recent advances in the design and syntheses reported mainly during the last three years are highlighted, with special emphasis on new trends for superior applications of these hybrid materials.

Anion-Responsive Metallopolymer Hydrogels for Healthcare Applications

Metallopolymers combine a processable, versatile organic polymeric skeleton with functional metals, providing multiple functions and methodologies in materials science. Taking advantage of cationic cobaltocenium as the key building block, organogels could be simply switched to hydrogels via a highly efficient ion exchange. With the unique ionic complexion ability, cobaltocenium moieties provide a robust soft substrate for recycling antibiotics from water. The essential polyelectrolyte nature offers the metallopolymer hydrogels to kill multidrug resistant bacteria. The multifunctional characteristics of these hydrogels highlight the potential for metallopolymers in the field of healthcare and environmental treatment.

A poly(polyoxometalate)-b-poly(hexanoic acid) block copolymer: synthesis, self-assembled micelles and catalytic activity

A poly(polyoxometalate)-polymer hybrid block copolymer (H-BCP) was prepared via ring-opening metathesis polymerization (ROMP). The H-BCP self-assembles into hybrid micelles with a poly(polyoxometalate) shell and a polymer core in acetonitrile.

Polymers containing nickel(II) complexes of Goedken's macrocycle: optimized synthesis and electrochemical characterization

The synthesis and characterization of a new class of nickel-containing polymers is described. The optimized copolymerization of alkyne-bearing nickel(II) complexes of Goedken's macrocycle (4,11-dihydro-5,7,12,14-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine) and brominated 9,9-dihexylfluorene produced polymers with potential application as functional redox-active materials. The title polymers exhibit electrochemically reversible, ligand-centered oxidation events at 0.24 and 0.73 V versus the ferrocene/ferrocenium redox couple. They also display exceptional thermal stability and interesting absorption properties due to the presence of the macrocyclic nickel(II) complexes and π-conjugated units incorporated in their backbones.

Ring-opening metathesis polymerization of 18-e Cobalt(I)-containing norbornene and application as heterogeneous macromolecular catalyst in atom transfer radical polymerization

In the last decades, metallopolymers have received great attention due to their various applications in the fields of materials and chemistry. In this article, a neutral 18-electron exo-substituted η(4) -cyclopentadiene CpCo(I) unit-containing polymer is prepared in a controlled/"living" fashion by combining facile click chemistry and ring-opening meta-thesis polymerization (ROMP). This Co(I)-containing polymer is further used as a heterogeneous macromolecular catalyst for atom transfer radical polymerization (ATRP) of methyl methacrylate and styrene.

Incorporation of Polyoxometalates into Polymers to Create Linear Poly(polyoxometalate)s with Catalytic Function

Organic polymers have been found widespread commercial applications due to their easy processing and attractive mechanical properties. Concurrently, inorganic polyoxometalates (POMs), a class of metal-oxygen anionic and nanosized clusters of early transition metals, have a wide range of attractive functions and are used in industrial catalysis. In this communication, we report a new approach to creating the first linear poly(polyoxometalate)s that combine the advantages of polymers and POM clusters. In the experiment, a POM-containing norbornene monomer was first synthesized by linking a Wells-Dawson-type POM with a norbornene derivative. The monomer was polymerized in the presence of a Grubbs catalyst under mild conditions with yields nearly 100% in a living and controllable manner. The resulting poly(polyoxometalate)s have controllable molecular weights and a well-defined hybrid structure of an organic polynorbornene backbone with large pendant groups of the nanosized POM clusters. Thus, they form good films and have a good catalytic performance. Our findings not only pave the way for incorporating the POM clusters into polymers with well-defined structures and high molecular weights, but also offer a competitive strategy for developing more novel catalytic systems by introducing the poly(polyoxometalate)s.

Sandwich complex-containing macromolecules: property tunability through versatile synthesis

Sandwich complexes feature unique properties as the physical and electronic properties of a hydrocarbon ligand or its derivative are integrated into the physical, electronic, magnetic, and optical properties of a metal. Incorporation of these complexes into macromolecules results in intriguing physical, electrical, and optical properties that were hitherto unknown in organic-based macromolecules. These properties are tunable through well-designed synthetic strategies. This review surveys many of the synthetic approaches that have resulted in tuning the properties of sandwich complex-containing macromolecules. While the past two decades have seen an ever-growing number of research publications in this field, gaps remain to be filled. Thus, we expect this review to stimulate research interest towards bridging these gaps, which include the insolubility of some of these macromolecules as well as expanding the scope of the sandwich complexes.

Aggregation-induced emission block copolymers based on ring-opening metathesis polymerization

AIE amphiphilic block copolymers were developed from ROMP for the first time. By self-assembly in selective solvents, water soluble fluorescent nano-objects were prepared with varied structures including micelles and vesicles.