Polymers metal-binding

Molecular motion of chemically modified wood is influenced by binding metal ions. One factors is valency, as mentioned previously. In general, however, there is not only valency but also other factors related to mobility [45-47]. Eisenberg reported that the mobility of polymers binding metal ions relates to three factors charge, amount of metal ion, and metal ion radii [48]. The mobility of molecules of carboxymethylated wood, especially that of... 

PDMP is the first member of the polyalkylphosphazene series. These polymers are very attractive supports for metals because of their high thermal stability and the presence of the basic nitrogen in the main chain, which is able to bind metal atoms. 

Similarly, this amphiphilic polymer micelle was also used to dismpt the complex between cytochrome c (Cc) and cytochrome c peroxidase (CcP Sandanaraj, Bayraktar et al. 2007). In this case, we found that the polymer modulates the redox properties of the protein upon binding. The polymer binding exposes the heme cofactor of the protein, which is buried in the protein and alters the coordination environment of the metal. The exposure of heme was confirmed by UV-vis, CD spectroscopy, fluorescence spectroscopy, and electrochemical kinetic smdies. The rate constant of electron transfer (fc°) increased by 3 orders of magnimde for the protein-polymer complex compared to protein alone. To establish that the polymer micelle is capable of disrupting the Cc-CcP complex, the polymer micelle was added to the preformed Cc-CcP complex. The observed for this complex was the same as that of the Cc-polymer complex, which confirms that the polymer micelle is indeed capable of disrupting the Cc-CcP complex. 

Chitosan is a polymer with metal-binding properties that is derived from naturally occurring chitin. Research has been conducted on the potential use of chitosan in hazardous waste remediation. While chitosan does bind transition metals, it favors iron, a nonhazardous metal, which competes and interferes with chitosan s binding of toxic metals. Copper also tends to be highly bound, while the amount of cadmium and lead removed is lower. The technology is still undergoing testing and is not yet commercially available. 

When the pendant crown ether groups bind metal ions, the phase separation temperature is expected to rise because the hydrophilicity of the polymer increases. The concentration change of special metal ions in solution can be detected as the phase transition of the polymer solution, or the conformation change of the polymer chain. 

Certain polymers are able to bind metal ions by chelating. The heterogeneous oxidation during combustion is thereby affected. An example is the polymer formed... 

The advantage of the coordinative polymer binding (structures C, D) is the easy way of preparation. Normally, only solutions of polymer ligand and lofw molecular metal chelate are mixed (Scheme 2). 

The coordinative polymer binding of metal phtalocyanines was examined using polymer ligands like poly(ethylene imine) , poly(vinylamine) , poly(acrylamide) mo fied by dipropylenetriamine and silicagel modified by y-amino-propyl-triethoxysilan . ... 

In particular, binding of metal cations at phosphate-phosphate contacts is vital to folding of RNA polymers. Cationic metal complexes may have the ability to target these important cation binding sites and reveal important phosphate-phosphate contacts. However, the different reactivities of DNA and RNA toward oxidation by metal complexes must also be considered (73-75), as will be discussed in some detail later. 

Polymers provide metal NP stabilization not only because of the steric bulk of their framework, but also by weak binding to the NP surface by the heteroatom, playing the role of ligands. Poly(N-vinyl-2-pyrrolidone) (PVP) is the most commonly used polymer for NP stabilization and catalysis, because it fulfils both steric and ligand requirements [5f. For instance Pt-, Pd- and RhNPs stabilized by PVP, are synthesized by refluxing ethanolic reduction of the corresponding metal halide and immobilized in an ionic liquid, l-n-butyl-3-methylimidazolium hexafluorophos-phate ([BMI][PF 5]), and are very efficient olefin and benzene hydrogenation catalysts at 40 °C that can be recycled without loss of activity (see Chart 1.1 for the two major polymer formulas used for NP catalysis) [12k]. 

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