Polymer , generally metal complexes

In other reactions, particularly where strongly complexing reactants, e. g., carbon monoxide, are involved, leaching of the immobilized metal center may take place. Generally, the parameters to be considered in a polymer-anchored metal complex catalyst are of a manifold nature. It is still an unsolved problem and an incompatible situation that, on the one hand, a leaching process should be avoided while, on the other hand, sufficient activity and the selectivity necessary for industrial applications are to be maintained. As a consequence it has become... 

Piezochromism has been observed in a wide variety of materials. Three classes which illustrate well some of the generalizations that have been developed are organic molecules in crystals and polymer films, metal cluster compounds, and organometaUic complexes of Cu(II). 

Cyanoacrylate adhesives cure by anionic polymerization. This reaction is catalyzed by weak bases (such as water), so the adhesives are generally stabilized by the inclusion of a weak acid in the formulation. While adhesion of cyanoacrylates to bare metals and many polymers is excellent, bonding to polyolefins requires a surface modifying primer. Solutions of chlorinated polyolefin oligomers, fran-sition metal complexes, and organic bases such as tertiary amines can greatly enhance cyanoacrylate adhesion to these surfaces [72]. The solvent is a critical component of these primers, as solvent swelling of the surface facilitates inter-... 

A number of examples of the introduction of the metal onto the support have already been mentioned in the previous section either because one of the ligands coordinated to the metal became part of the polymer [see reactions (4) and (18)—(20)] or because the metal complex reacted directly with the support [reactions (1) and (2)] or because the preparation simply involved sorption by van der Waals forces onto the support (Section I). In the present section, we shall be particularly concerned to introduce metal complexes onto polymeric supports that have typical donor groups such as tertiary phosphine and amine. A number of routes, most of which are of fairly general applicability, have been used. 

In general, the polymer ligand surrounding the metal complex constitutes an electrostatic or hydrophobic domain in aqueous solution. This polymer domain governs the chemical reactivity of the metal complex. This phenomenon is said to be an environmental effect of polymer on a chemical reaction. 

In general, the reactivity of a polymer-metal complex can be controlled by the higher structure of the polymer chain and the dynamic change in its conformation. 

In general, the thermal stability of metal-containing polymer systems is relatively enchanced compared to that of the bulk polymer. Various factors including size and concentration of the metal ions, and crystal field stabilization energy of the anchored metal complexes influence the stability to different extents. 

In the most important series of polymers of this type, the metallotetraphenylporphyrins, a metalloporphyrin ring bears four substituted phenylene groups X, as is shown in 7.19. The metals M in the structure are typically iron, cobalt, or nickel cations, and the substituents on the phenylene groups include -NH2, -NR2, and -OH. These polymers are generally insoluble. Some have been prepared by electro-oxidative polymerizations in the form of electroactive films on electrode surfaces.79 The cobalt-metallated polymer is of particular interest since it is an electrocatalyst for the reduction of dioxygen. Films of poly(trisbipyridine)-metal complexes also have interesting electrochemical properties, in particular electrochromism and electrical conductivity.78 The closely related polymer, poly(2-vinylpyridine), also forms metal complexes, for example with copper(II) chloride.80... 

Other important methods of synthesis of coordination compounds are discussed in detail [1,3,10,11,53,201,202,206,207,316,318,322,690]. In this respect, we emphasize the synthesis of metal-polymers [690,691] and preparation of complexes in the solid phase (mechano- or tribosynthesis) [10,201,202,206]. Additionally to the above-described techniques, the general methods and principles of synthesis of coordination compounds are used to obtain metal-polymers (immediate interaction of polymer ligands and metal salts, template electrosynthesis, polymer-analogous transformations). The last method consists of the polymerization of metal-monomers (metal-containing monomers) and fixation of metal complexes on the polymer... 

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