Metal-polymer complexes

Tsuchida, E. and Nishide, H. Polymer-Metal Complexes and Their Catalytic Activity. Vol. 24, pp. 1-87. 

The Cu-complex-catalyzed oxidative polymerization of phenol derivatives has been selected here as a model reaction in which a polymer-metal complex acts as a catalyst. The catalytic cycle is illustrated in Scheme 3, the example used being the oxidative... 

Note 2 Examples of polymer-supported catalysts are (a) a polymer-metal complex that can coordinate reactants, (b) colloidal palladium dispersed in a swollen network polymer that can act as a hydrogenation catalyst. 

For example, the aggregated structures of the solutions containing polymer-metal complexes and the colloidal dispersions of metal nanoparticles stabilized by polymers have been analyzed quantitatively (64). SAXS analyses of colloidal dispersions of Pi, Rh, and Pt/Rh (1/1) nanoparticles stabilized by PVP have indicated that spatial distributions of metal nanoparticles in colloidal dispersions are different from each other. The superstructure (greater than 10.0 nm in diameter), with average size highly dependent on the metal element employed, is proposed. These superstructures are composed of several fundamental clusters with a diameter of 2.0-4.0 nm, as shown in Figure 9.1.13 for PVP-stabilized Pt nanoparticles. 

New Photodiode Composed of a Polymer-metal Complex Film... 

Conductive polymers are useful semiconductors or coating materials to construct solar cells. A new photodiode is proposed to be made from a film of a polymer metal complex. Immobilized catalysts on polymers are used for solar energy storage systems. 

Polymer-Metal Complexes and Their Catalytic Activity... 

This article deals with the polymer-metal complexes (Schemes 1 —5), because they have the following merits in comparison with other polymeric metal complexes, (i) Metal ion and ligand site can be chosen for study without restrictions, (ii) It is not difficult to control the molecular weight of a polymer complex and to modify the structure of a polymer ligand, (iii) The polymer complex is soluble in both aqueous and nonaqueous solvent, (iv) It is possible to change the ratio of the organic polymer part to the inorganic metal complex part. This explains why the polymer often affects the behavior of the metal complex. 

It is the purpose of this article to discuss whether or not there are any differences between the chemical reactivity of a polymer-metal complex and that of the corresponding monomeric complex. Although various extensive investigations on polymer-metal complexes have been reported, most of these complexes are too complicated to be discussed quantitatively due to the nonuniformity of their structure. These compounds include not only complexes of macromolecules but also the structurally labile metal complex . Before detailed information can be obtained about the properties of polymer-metal complexes, and especially about the reactivity and catalytic activity of polymer-metal complexes, their structure must be elucidated. A polymer-metal complex having a uniform structure may be defined as follows ... 

These discussions will embrace homogeneous solutions of polymer-metal complexes. Of course one of the important advantages offered by the use of a polymer ligand, especially a crosslinked polymer ligand, in catalysis is the insolubilization of the attached complexes the insolubility of the polymer catalyst makes it very easy to separate from the other components of the reaction mixture. Several polymer-metal complexes have been used for this purpose, although such applications are not covered in this article. The aim here is (1) to characterize polymer-metal complexes and their behavior in such simple but important elementary reactions as complex formation, ligand substitution, and electron transfer, and (2) to describe their catalytic activity. 

II. Formation and Structure of Pendant-Type Polymer-Metal Complexes... 

Examples of the pendant-type polymer-metal complexes represented by Schemes 4 and 5 are shown in Table 2. They are obtained by the reaction in Scheme 8 a polymer ligand is made to coordinate to a vacant site of a previously prepared, stable, low-molecular-weight metal complex. The structure and hence the functions of the metal complex are hardly changed by attachment to the polymer ligand. The metal complexes attached to the polymer ligands 1 to 8 are the classic cobaltic... 

We prepared a series of pendant-type polymer-metal complexes having a uniform structure by the substitution reaction between a polymer ligand and a Co(III) or Cr(III) chelate, the chelate being inert in ligand-substitution reactions1,2 A poly-mer-Co(III) complex, e.g. ci s-[Co(en)2(PVP)Cl]Cl2 (en=ethylenediamine, PVP= poly(4-vinylpyridine)) i 7, was prepared as follows11 ... 

Table 2. Pendant-type polymer-metal complexes...

If a monomeric metal complex containing a vinyl group is polymerized without side reactions, a polymer-metal complex having uniform structure can be obtained. 

---