Synthetic polymers containing metal centres are emerging as an interesting and broad class of easily processable materials with properties and functions that complement those of state-of-the-art organic macromolecular materials. A diverse range of different metal centres can be harnessed to tune macromolecular properties, from transition- and main-group metals to lanthanides. Moreover, the linkages that bind the metal centres can vary almost continuously from strong, essentially covalent bonds that lead to irreversible or 'static' binding of the metal to weak and labile, non-covalent coordination interactions that allow for reversible, 'dynamic' or 'metallosupramolecular', binding. Here we review recent advances and challenges in the field and illustrate developments towards applications as emissive and photovoltaic materials; as optical limiters; in nanoelectronics, information storage, nanopatterning and sensing; as macromolecular catalysts and artificial enzymes; and as stimuli-responsive materials. We focus on materials in which the metal centres provide function; although they can also play a structural role, systems where this is solely their purpose have not been discussed.
"Water-soluble poly(ferrocenylsilanes) (PFSs) are fascinating building blocks for stimuliresponsive hydrogels. These organometallic polymers have received considerable attention due to useful properties such as a high etch resistance and redox-activity, owing to the presence of Fe and Si atoms in the PFS main chain. High-molar-mass PFSs, consisting of skeletal organosilane and ferrocene units, are readily available via the ring-opening polymerization of the silicon-bridged ferrocenophane monomers and can be readily derivatized. "
[Show abstract][Hide abstract] ABSTRACT: Redox responsive hydrogel thin films consisting of poly(ferrocenyl(3-bromopropyl)methylsilane) were fabricated by crosslinking the polymer with N,N,N’,N”,N”-pentamethyldiethylenetriamine (PMDETA). Owing to the presence of ferrocene in the redox-active PFS chains, the thin hydrogel films could be oxidized and reduced chemically and electrochemically. The thin films could be used as a reducing environment for the in-situ formation of Pd nanoparticles, yielding PFS hydrogel-nanoparticle composites, which were employed directly in the electrocatalytic oxidation of ethanol. Pronounced catalytic activity of the Pd-loaded hydrogel films was observed.
European Polymer Journal 05/2015; DOI:10.1016/j.eurpolymj.2015.05.022 · 3.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A new class of soluble, solution-processable heterobimetallic platinum(II)-acetylide polymers functionalized with some rhenium(I)-bithiazole based spacers and their corresponding model complexes were synthesized and characterized. The photophysical (absorption and emission spectra), thermal and electrochemical properties of the polymers were investigated in detail. These mixed-metal PtRe polymers exhibited good thermal stability and strong low-energy broad absorption bands in the visible region. The effects of metal complexation of the bithiazole group with ReCl(CO)5 as well as adding thiophene ring along the polymer backbone on the optical bandgaps of these organometallic polymers were examined. The bandgaps of these polymers were found to be controllable readily by chemical means and can be lowered from 2.18 to 1.89 eV as the number of thiophene ring was increased from 0 to 2. Upon coordination with Re(CO)3Cl moiety, the optical gap of the polymer can be reduced by as large as 0.25 eV.
[Show abstract][Hide abstract] ABSTRACT: A new ferrocene-based poly(azomethine)ester (P) was synthesized via solution polycondensation of 1,1′-di(chlorocarboxyl) ferrocene with a novel preformed 4-((4-(4-(4-hydroxybenzylideneamino)phenoxy)phenylimino)methyl)phenol (SB). The condensation copolymers with good solubility were obtained using commercially available aliphatic (1,3-propan-diol, 1,6-hexan-diol and poly(dimethylsiloxane), hydroxyl-terminated (n = 550)) and aromatic ((1,1,1,3,3,3-hexaflouro)bisphenol propane and bisphenol A) along with the synthesized monomer (SB) and 1,1′-di(chlorocarboxyl) ferrocene. The obtained compounds were characterized by elemental analysis, FTIR and 1H NMR spectrophotometric techniques. The structure–property relation was studied in term of solubility measurements, WAXRD and UV–visible spectroscopic techniques. Average molecular weights, Mw obtained by laser light scattering method were found to be of the order 105 g/mol. Thermogravimetric curves along with polarized optical micrographs were also recorded. SEM–EDX and AFM techniques were employed to study the surface morphology of the synthesized material. Whereas the redox properties were explored using cyclic voltammetric investigations. The biological activity of the synthesized material was studied by utilizing various biological assays (antibacterical, brine shrimp cytotoxicity, antitumor potato disc, DPPH free radical scavenging and free radical induced oxidative DNA damage analysis). In case of brine shrimp (Artemia salina) lethality assay PSi and PF showed LD50 < 1 ppm indicating highly toxic behavior. PF resulted IC50 = 37.78 in tumor inhibition assay. The Schiff base (SB) was highly antioxidant with IC50 = 2.05 ppm and fully protected the plasmid DNA from damage. All the compounds studied were found potent antioxidants, highly cytotoxic and more importantly DNA protecting. The influence of aromatic and aliphatic segments on the properties of organometallic poly(azomethine)ester is discussed.
Allison B Churnside, Ryan C Tung, Jason P Killgore
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