Metallopolymer formation

Less often, nanoparticles are formed on polymers by means of electrophoretic and electrochemical deposition of metals onto an added polymeric suspension. The metallopolymer formation results from the polarizational of polymer and metal particles during deposition on the electrode followed by chemisorption of macromolecules at the metal sinface at the moment of its reduction. This process includes... 

Metalloorganic liquids, characteristics, 1, 853 Metallopolymers, with n-coordinated metals, 12, 311 Metallosilanes, preparation methods, 3, 521 Metallostannation, in tin-carbon bond formation, 3, 817 Metal-metal bonds... 

The second stage is the formation of a film from the metallopolymer solution by a glaze method and slow (10-15 h) evacuation of the solvent to a residual percentage of 5-10%. The resulting metastable membrane film is freed from parent salt by washing with methanol or water. Finally, the third stage, reduction, is very quick the formed particles are linked to polymer chains (Fig. 8-6, bold points). 

The conformational prearranged effect of both the macromolecular ligand with respect to a certain metal ion and the active sites of metallopolymer catalysts to a substrate was observed in liquid-phase oxidations of alkylaromatic hydrocarbons recently the same was found in the case of hydroxyarenes [135-137]. Initially, a soluble metallocomplex is formed in the presence of metal ions or substrate. A structural rearrangement, specific to the reacting compounds, is further fixed in the process by cross-linking of the polymer support by AA -methylenediacrylamide with a subsequent removal of pattern substrates from cross-linked formations. Such an approach leads to a substantial increase of selectivity and activity of the catalyst in comparison with a catalyst obtained without directed generation of its structure. 

Similar metallopolymers based on diphenylphosphine-terminated macromonomers in combination with Rh" or Ir ions resulted in the formation of gel-like networks when the building blocks were combined in a solvent such as dichloromethane or chloroform [91]. These gels could be liquehed upon ultrasonication (Fig. 27) as a result of ligand exchanges that preserved the coordination stoichiometry of the metal centers while reducing the number of cross-links. After sonication, the equilibrium network reformed almost immediately in the case of Rh" (gel phase after 1 h at -i-20°C), whereas the process was much slower in the case of the Ir -based gel (sol phase still present after 3 days at —20°C). 

Fig. 7.8 The first ten repeated scans for the formation of polymer 7.44 (M = Cu) by oxidative electropolymerization on the working electrode. Electroactivity increases at ca. 0.6-0.7 V with each additional scan, indicating the progressive formation of a film of the metallopolymer on the electrode. Solution in CH2CI2 (5x10- M in monomer) with [Bu4N][PFs] as supporting electrolyte. Scan rate 100 mV s (Adapted from [82])...

All the Schiff s base complexes discussed so far are low-molecular weight complexes. An erbium(lll)-containing methacrylate metallopolymer was prepared by free-radical polymerization of a Schiff s base monomer LllH, followed by complex formation with hydrated erbium nitrate (Haase et al., 1996). By XRD, the presence of a smectic mesophase was shown. A special feature of the polymer is that the complexing group is an Ai-aryl substituted Schiff s base, rather than an Ai-alkyl substituted one. No further structural data were reported. A detailed study of the mesophase behavior of lanthanide complexes of Ai-aryl substituted Schiff s base ligands LllH was reported by Rao et al. (2002, 2010). The complexes were synthesized by reaction between the... 

In this chapter, procedures for the preparation of metallopolymer nanocomposites of different types, especially hybrid organic-inorganic ones, are considered from a unified viewpoint and ffie generality of the processes of their formation in living and nonliving natural objects is demonstrated. This review smweys fresh results and those generally published wiffiin the last decade. 

As the synthesis of metallopolymer complexes precedes the formation of metallopolymer nanocomposites, let us consider briefly these problems. 

Such polymer conversion methods were used to prepare Ba, and Cu + complexes with poly(methacrylic acid)" " and YBC chelates with polyamides." "" " Gel formation with poly(vinyl alcohol) (PVA) can also be used." The superconducting ceramics based on these metallopolymers have values = 80-92K, and critical current densities (J ) of 150-160 A cm . Films and fibers in addition to powders, can be prepared from these ceramics. YBC-epoxy composites are also suitable for this pur-pose." ... 

In either case, electrochemical reduction generates radicals which lead to carbon-carbon bond formation and oligomerization. Oligomers above a critical size are insoluble and thus thin films of the electroactive metallopolymer are produced on the electrode surface. As noted above, the color of such metallopolymer films in the M(II) redox state may be selected by suitable choice of the metal. 

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