Search Results (40)

A strategy based on the hyperbranched polyol process (HB-polyol process) is presented for the synthesis of hemocompatible cobalt nanocomposites Co/G_nOH with controlled morphology and predictable functional properties. Third-generation (G₃OH) and fourth-generation (G₄OH) hyperbranched polyester polyols were used as smart polyol nanoreactors. We establish, for the first time, the fundamental physicochemical principles of the HB-polyol process based on a comprehensive analysis of FT-IR, UV-Vis, NMR, NTA, and TEM data. These principles encompass the stages of pre-organization, nucleation, polyol oxidation and the stabilization of cobalt-loaded metallopolymer nanocomposites within the binary [CoCl₂–G_nOH] system (n = 3, 4). Magnetic measurements revealed that the samples exhibit paramagnetic properties at 5 K. The size of the magnetic cores in the Co/G₃OH samples was estimated by fitting the field-dependent magnetization curves to the Langevin function and was found to range from 1.4 nm to 7.2 nm, indicating the superparamagnetic behavior of the nanocomposites. In vitro biological tests of the Co/G_nOH nanocomposites demonstrated high hemocompatibility, as well as pronounced modulatory and antimycotic activity across all samples. The obtained results hold promise for the development of simple design technologies for multifunctional “intelligent” materials based on metal and dendritic nanoparticles for biomedical applications. Full article

In this work, we elaborately designed two nickel(II) Schiff base complexes (NiL and NiL’) with different π-conjugated systems (benzene vs. naphthalene) to prepare uniform metallopolymer films with nickel(II) chelates as repeating units on ITO substrates through oxidative electropolymerization. The π-conjugation extending from the benzene moiety to the naphthalene moiety greatly enhances the electron delocalization of the metallopolymer film, resulting in a significant increase in optical contrast from 25% ([NiL]_n) to 80% ([NiL’]_n). The solid-state electrochromic devices based on metallopolymer film [NiL’]_n achieved a transmittance modulation of 71% and an electrochromic efficiency of 268.58 cm² C⁻¹. This work provides an effective strategy for developing low-cost and high-performance non-precious metal electrochromic materials through ligand conjugation engineering. Full article

Background/Objectives: Copper levels are significantly elevated in both the sera and tumor tissues of various cancers, including prostate cancer. It has therefore been suggested that targeting the elevated copper levels with copper chelators could lead to selective cancer treatment. Thus, several classes of low molecular weight copper-coordinating lipophilic compounds, as well as the newly developed copper complexes of appropriately functionalized polymers, are being investigated as promising novel anticancer therapeutics. Particularly, metal-containing polymers, or metallopolymers, are systematically investigated as anticancer agents or as drug delivery systems. This study aims to utilize the strong copper-chelating properties of hyperbranched polyethyleneimine (PEI) to develop PEI:Cu metallopolymers and evaluate their selectivity and anticancer properties against several prostate cancer cell lines. Methods: A series of PEI:Cu complexes at PEI/Cu ratios that ensure that no free copper ions are present in the solution are prepared and investigated against a human non-cancerous cell line and three prostate cancer cell lines of increasing metastatic potential. Results: PEI:Cu derivatives are cytotoxic against the human prostate carcinoma metastatic PC3 and DU145 cell lines, even at the lowest tested concentrations of 5 μg/mL, while against the non-cancerous HEK293 cells, all metallopolymer derivatives exhibit insignificant cytotoxicity up concentrations of 50 μg/mL. Their cytotoxic effect is associated with mitochondria membrane potential loss and ROS production increase. Conclusions: Hyperbranched polyethyleneimine–coordinated copper(II) metallopolymers, at low concentrations, selectively induce cytotoxicity in metastatic prostate cancer cell lines without compromising the viability of non-cancerous embryonic kidney cells. Full article

π-conjugated polymers are arguably one of the most exciting classes of materials and have attracted substantial attention due to their unique optical and electronic properties. The introduction of transition metals into conjugated polymers tunes the optoelectronic properties of these metallopolymers, which may improve their performance in device applications. Graphene and reduced graphene oxide (RGO) derivatives are interesting materials with a unique structure and outstanding properties. The present work reports an investigation of three hybrid RGO and π-conjugated oligomers that contain ruthenium polypyridyl chromophores serving as models to provide molecular-level insight for the corresponding transition-metal-containing conjugated polymers. Full article

The utilization of self-healing polymers is a promising way of solving problems associated with the wear and tear of polymer products, such as those caused by mechanical stress or environmental factors. In this study, a series of novel self-healing, high-strength copolymers of acrylamide, acrylic acid, and novel acrylic complexes of 4′-phenyl-2,2′:6′,2″-terpyridine [Co(II), Ni(II), and Cu(II)] was prepared. A systematic study of the composition and properties of the obtained polymers was carried out using a variety of physicochemical techniques (elemental analysis, gel permeation chromatography (GPC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR), ultraviolet-visible spectroscopy (UV-vis), small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), confocal laser scanning microscopy (CLSM), and tensile testing). All metallopolymer samples exhibit autonomous intrinsic healing along with maintaining high tensile strength values (for some samples, the initial tensile strength exceeded 100 MPa). The best values of healing efficiency are possessed by metallopolymers with a nickel complex (up to 83%), which is most likely due to the highest lability of the metal–heteroatom coordination bonds. The example of this system shows the ability to re-heal with negligible deterioration of the mechanical properties. The possibility of tuning the mechanical properties of self-healing films through the use of different metal ions has been demonstrated. Full article

This review focuses on functional materials that contain terpyridine (terpy) units, which can be synthesized from biomass-derived platform chemicals. The latter are obtained by the chemical conversion of raw biopolymers such as cellulose (e.g., 2-furaldehyde) or lignin (e.g., syringaldehyde). These biomass-derived platform chemicals serve as starting reagents for the preparation of many different terpyridine derivatives using various synthetic strategies (e.g., Kröhnke reaction, cross-coupling reactions). Chemical transformations of these terpyridines provide a broad range of different ligands with various functionalities to be used for the modification or construction of various materials. Either inorganic materials (such as oxides) or organic ones (such as polymers) can be combined with terpyridines to provide functional materials. Different strategies are presented for grafting terpy to materials, such as covalent grafting through a carboxylic acid or silanization. Furthermore, terpy can be used directly for the elaboration of functional materials via complexation with metals. The so-obtained functional materials find various applications, such as photovoltaic devices, heterogeneous catalysts, metal–organic frameworks (MOF), and metallopolymers. Finally, some possible developments are presented. Full article

In the pursuit of fabricating functional ceramic nanostructures, the design of preceramic functional polymers has garnered significant interest. With their easily adaptable chemical composition, molecular structure, and processing versatility, these polymers hold immense potential in this field. Our study succeeded in focusing on synthesizing ferrocene-containing block copolymers (BCPs) based on polyacrylonitrile (PAN). The synthesis is accomplished via different poly(acrylonitrile-block-methacrylate)s via atom transfer radical polymerization (ATRP) and activators regenerated by electron transfer ATRP (ARGET ATRP) for the PAN macroinitiators. The molecular weights of the BCPs range from 44 to 82 kDa with dispersities between 1.19 and 1.5 as determined by SEC measurements. The volume fraction of the PMMA block ranges from 0.16 to 0.75 as determined by NMR. The post-modification of the BCPs using 3-ferrocenyl propylamine has led to the creation of redox-responsive preceramic polymers. The thermal stabilization of the polymer film has resulted in stabilized morphologies based on the oxidative PAN chemistry. The final pyrolysis of the sacrificial block segment and conversion of the metallopolymer has led to the formation of a porous carbon network with an iron oxide functionalized surface, investigated by scanning electron microscopy (SEM), energy dispersive X-ray mapping (EDX), and powder X-ray diffraction (PXRD). These findings could have significant implications in various applications, demonstrating the practical value of our research in convenient ceramic material design. Full article

Terpyridine (TPY) platinum(II) chloride with a triphenylamine (TPA) group was successfully synthesized. The strong intramolecular Donor(TPA)-Acceptor(TPY) interaction induced the low-energy absorption band, mixing the spin-allowed singlet dπ(Pt)→π*(TPY) metal-to-ligand charge transfer (MLCT) with the chloride ligand-to-metal charge transfer (LMCT) and chloride ligand-to-ligand (TPY) charge transfer (LLCT) transitions, to bathochromically shift to λ_max = 449 nm with significant enhancement and broadening effects. Using the cyclic voltammetry method, its oxidative electropolymerization (EP) films on working Pt disk and ITO electrodes were produced with tunable thickness and diffusion controlled redox behavior, which were characterized by the SEM, EDS, FT-IR, and AC impedance methods. Upon applying +1.4 V voltage, the sandwich-type electrochromic device (ECD) with ca. 290 nm thickness of the EP film exhibits a distinct color transformation from red (CIE coordinates: L = 50.75, a = 18.58, b = 5.69) to dark blue (CIE coordinates: L = 45.65, a = −1.35, b = −12.49). Good electrochromic (EC) parameters, such as a large optical contrast (ΔT%) of 78%, quick coloration and bleaching response times of 2.9 s and 1.1 s, high coloration and bleaching efficiencies of 278.0 and 390.5 C⁻¹·cm², and good cycling stability (maintains 70% of the initial ΔT% value after 3200 voltage switching cycles), were obtained. Full article

A non-absorbable therapeutic candidate for the treatment of hyperammonemia has been identified and characterized. Conventional approaches to reducing ammonia concentration in the blood and colon include acidifying the colon, inhibiting the bacterial production of ammonia, and activation of the urea cycle. Addressing gaps in the literature around therapeutic ammonia adsorption, this study established assays for ammonia uptake from both NH₄OH and NH₄Cl solutions as well as interference and selectivity for potassium absorption. Performance was characterized for a large number and variety of materials, spanning zeolites, ion-exchange resins, metallopolymers, metal–organic frameworks (MOFs), and polymeric carboxylic acids. The latter class showed low potassium capacity (poly(acrylic acid): 10 mg/g, poly(maleic-co-acrylic acid): 4 mg/g) and a therapeutically relevant depression of pH in buffered simulated intestinal fluid (SIF) (poly(acrylic acid): −2.01 and poly(maleic-co-acrylic acid): −3.23) compared to lactulose (−3.46), an approved therapeutic for hyperammonemia that works by acidifying the colon. In the polymeric organic acids evaluated, pH depression correlated well with pKa and acid site density. Additionally, this class of candidates should avoid the undesirable side effects of lactulose, such as the potential for hyperglycemia in diabetic patients and incompatible use with galactosemic patients. Full article

A method for the design and synthesis of a metallopolymer composite (CoNP) based on cobalt nanoparticles using the hyperbranched polyol process was developed. It was shown that hyperbranched polyester polyols in a melted state can be both a reducing agent and a stabilizer of metal nanoparticles at the same time. The mechanism of oxidation of hyperbranched polyol was studied using diffuse reflectance IR spectroscopy. The process of oxidation of OH groups in G4-OH started from 90 °C and finished with the oxidation of aldehyde groups. The composition and properties of nanomaterials were determined with FT-IR and UV-Vis spectroscopy, Nanoparticle Tracking Analysis (NTA), thermogravimetric analysis (TG), powder X-ray diffraction (XRD), NMR relaxation, and in vitro biological tests. The cobalt-containing nanocomposite (CoNP) had a high colloidal stability and contained spheroid polymer aggregates with a diameter of 35–50 nm with immobilized cobalt nanoparticles of 5–7 nm. The values of R₂ and R₁ according to the NMR relaxation method for CoNPs were 6.77 mM·ms⁻¹ × 10⁻⁵ and 4.14 mM·ms⁻¹ × 10⁻⁵ for, respectively. The ratio R₂/R₁ = 0.61 defines the cobalt-containing nanocomposite as a T₁ contrast agent. The synthesized CoNPs were nonhemotoxic (HC₅₀ > 8 g/mL) multifunctional reagents and exhibited the properties of synthetic modulators of the enzymatic activity of chymosin aspartic proteinase and exhibited antimycotic activity against Aspergillus fumigatus. The results of the study show the unique prospects of the developed two-component method of the hyperbranched polyol process for the creation of colloidal multifunctional metal–polymer nanocomposites for theranostics. Full article

A novel one-dimensional malleable spin-crossover (SCO) complex {[Fe(MPEG-trz)₃](BF₄)₂} has been successfully synthesized by molecular self-assembly between 4-amino-1,2,4-triazoles (MPEG-trz) grafted with a long flexible chain methoxy polyethylene glycol (MPEG) and metallic complex Fe(BF₄)₂•6H₂O. The detailed structure information was illustrated by using FT-IR and ¹H NMR measurements, while the physical behaviors of the malleable SCO complexes were systematically investigated by using magnetic susceptibility measurements using superconductivity quantum interference device (SQUID) and differential scanning calorimetry (DSC). This new metallopolymer exhibits a remarkable spin crossover transition behavior, between two spin quantum states (Fe²⁺ ions): high spin (HS) state (quintet state) and low spin (LS) state (singlet state), at a specific critical temperature with a slender hysteresis loop of 1 K. DFT computations revealed the partial rules of HOMO-LUMO energy levels and spin density distributions of different four-position substituted [Fe(1,2,4-triazole)₃]²⁺ derivatives with different length of repeat units in polymer complexes. This can go a step further to depict the spin and magnetic transition behaviors of SCO polymer complexes. Furthermore, the coordination polymers possess an excellent processability due to an outstanding malleability, which can be easily shaped into a polymer film with spin magnetic switching properties. Full article

Among modern biomaterials, hybrid tools containing an organic component and a metal cation are recognized as added value, and, for many advanced biomedical applications, synthetic polymers are used as thin protective/functional coatings for medical or prosthetic devices and implants. These materials require specific non-degradability, biocompatibility, antimicrobial, and antiproliferative properties to address safety aspects concerning their use in medicine. Moreover, bioimaging monitoring of the biomedical device and/or implant through biological tissues is a desirable ability. This article reports a novel hybrid metallopolymer obtained by grafting zinc-coordinated fragments to an organic polymeric matrix. This hybrid polymer, owing to its relevant emission in the deep red to near-infrared (DR/NIR) region, is monitorable; therefore, it represents a potential material for biomedical coating. Furthermore, it shows good biocompatibility and adhesion properties and excellent stability in slightly acidic/basic water solutions. Finally, in contact with the superficial layers of human skin, it shows antimicrobial properties against Staphylococcus aureus bacterial strains. Full article

Conductive electrochemically active metallopolymers are outstanding materials for energy storage and conversion, electrocatalysis, electroanalysis, and other applications. The hybrid inorganic–organic nature of these materials ensures their rich chemistry and offers wide opportunities for fine-tuning their functional properties. The electrochemical modulation of the nanomechanical properties of metallopolymers is rarely investigated, and the correlations between the structure, stiffness, and capacitive properties of these materials have not yet been reported. We use electrochemical atomic force microscopy (EC-AFM) to perform in-situ quantitative nanomechanical measurements of two Schiff base metallopolymers, poly[NiSalphen] and its derivative that contains two methoxy substituents in the bridging phenylene diimine unit poly[NiSalphen(CH₃O)₂], during their polarization in the electrolyte solution to the undoped and fully doped states. We also get insight into the electrochemical p-doping of these polymers using electrochemical quartz crystal microgravimetry (EQCM) coupled with cyclic voltammetry (CV). Combined findings for the structurally similar polymers with different interchain interactions led us to propose a correlation between Young’s modulus of the material, its maximum doping level, and ion and solvent fluxes in the polymer films upon electrochemical oxidation. Full article

This review is devoted to the description of methods for the self-healing of polymers, polymer composites, and coatings. The self-healing of damages that occur during the operation of the corresponding structures makes it possible to extend the service life of the latter, and in this case, the problem of saving non-renewable resources is simultaneously solved. Two strategies are considered: (a) creating reversible crosslinks in the thermoplastic and (b) introducing a healing agent into cracks. Bond exchange reactions in network polymers (a) proceed as a dissociative process, in which crosslinks are split into their constituent reactive fragments with subsequent regeneration, or as an associative process, the limiting stage of which is the interaction of the reactive end group and the crosslink. The latter process is implemented in vitrimers. Strategy (b) is associated with the use of containers (hollow glass fibers, capsules, microvessels) that burst under the action of a crack. Particular attention is paid to self-healing processes in metallopolymer systems. Full article