Polymeric metal complexe

A. D. Pomogailo, Immobilized Polymeric-Metal Complex Catalysis (in Russian), Khimiya, Moscow (1986). 

Sherrington et al. were the first to attempt the synthesis of chiral polymeric metal complexes by the chemical modification route,78,177,178 whereby the [Mn(salen)Cl] units are attached in a pendant fashion, by only one of the aromatic rings, to poly(styrene) or poly(methacrylate) resin beads of various morphology. Epoxidation of 1-phenylcyclohexene gave enantioselectivity values between 61% and 91%. 

A wide variety of investigations have been carried out on polymeric metal complexes these include studies of semiconductivity, thermostability, redox reactions, collection of metal ions, biomedical effects, and so on. The polymeric metal complexes are classified into the following groups ... 

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. 

Fryd [4] prepared organic emitting materials consisting of polymeric-metal complex salts, (IV). Their preparation is illustrated in below. 

In recent years, there has been much interest in the study of polymer complexes, particularly in relation to their catalyst properties, thermostability and biomedical effects. Mainly these studies have been directed towards the use of insoluble polymers. An account of the soluble polymeric metal complexes and their catalytic activity has been published recently A brief outline of the studies in relation to the n M-chelation of some linear hydrophilic polymers and their functional derivatives with chelating groups and some polymeric molecular complexes is given in this section. 

This probably cannot be accounted for on the basis of steric effects, but may have its origin in greater solubility in the case of the stilbazole as opposed to vpy or BPE-containing polymeric metal complex chains, which results in much lower surface coverages. 

Covalent bonding refers to the materials made in which the transition metal is bonded directly to the resin through an organometallic bond. Two different approaches can be used to covalently attach metal complexes to polymer supports (i) synthesis of appropriate functional monomers and their (co)polymerization to form catalytically active polymers (Scheme 11.1) or (ii) attachment of metal complexes to preformed functional polymer supports by chemical reactions. Following these approaches, both soluble and cross-linked chiral polymeric metal complexes can be prepared. An example of an organometallic tin catalyst suitable for transesterification was reported by workers at Rohm and Haas Company [3]. 

Pyrazine (L39) and substituted pyrazines have long been known to act as exo-didentate ligands to linearly bridge metal ions, generating oligomeric and polymeric metal complexes with infinite chain and... 

Shortening the bridges connecting the two cyclopentadiehe rings with one another is realized in compound 112 (Fig. 25) [99]. After simple deprotonation preparation of heterobimetallic complexes such as 116 is possible [100], or alternatively double deprotonation of 115 provides access to one-dimensional polymeric metal complexes (Fig. 25) [100, 101]. 

Two principal routes are used to s)mthesize the polymeric metal complexes described in Sections 6.1 and 6.2 (Fig. 6-1) ... 

Route B Several examples are also known where a ligand/chelate precursor is reacted with a polymer ligand or in another case in the presence of a metal ion as template directly under construction of a polymeric metal complex. Difficulties can arise from side-reactions which mean that other reaction products can also be formed. The disadvantage is that such side-products are also covalently incorporated into the polymer, and no purification is possible. Therefore detailed design of the synthesis and then careful analysis is necessary. 

The incorporation of a rigid metal complex in a polymer chain reduces the solubility and processibility as is known for aromatic polyamides or polyesters. Polymeric metal complexes with aliphatic alkylene moieties between the chelate units or bulky groups as substituents are easier to handle. Cross-linked polymeric metal complexes are, of course, more difficult to analyze. 

Polymeric Metal Complexes with Noncyclic Organic Ligands... 

Polymeric Metal Complexes with Cyclic Organic Ligands 239... 

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