Macromolecular metal complexes formation

B. Kinetical, Thermodynamical, and Analytical Aspects of Macromolecular Metal Complex Formation... 

This book provides an overview of possible combinations of metal complexes and metals with organic and inorganic macromolecules (often also named macromolecular metal complexes — MMC [1]). This book covers the formation, synthesis, structure and properties of these exciting and relatively new materials. Metal-containing macromolecules are a fascinating field of science. It is readily understandable that materials with unusual properties are obtained by having a metal complex or metal as part of a macromolecule. Nature shows us the functions of such materials extremely well by the selectivity and activity of, for example, hemoglobin, photosynthesis and metalloenzymes. 

Kinetics and Thermodynamics of Formation of Macromolecular Metal Complexes and Their Structural Organization... 

Chapter 3 concentrates on different aspects of the formation of macromolecular metal complexes (MMCs) by interaction of a macromolecular ligand with a metal compound MX . Such metal-containing macromolecules are classified in Section 1.2.1 as type I. Chapter 4 concentrates on polymerizations of metal-containing monomers. Examples of the binding of MX at macromolecular ligands are given in more detail in Chapter 5. The kinetics and thermodynamics of formation of macromolecular metal complexes of type II, type III and type rv are not known in detail. A few aspects are included in Chapters 6, 7 and 8. 

Chapters 1 and 2 of Part A PREFACE introduce into definitions, classifications, history, properties and biological systems of macromolecular metal complexes. Then part B SYNTHESIS AND STRUCTURES contain at first in chapter 3 kinetics and thermodynamics of formation of these complexes. The following chapters 4 till 8 describe in detail the various synthetic routes for the preparation of macromolecular metal complexes. Part C with chapters 9 till 14 is devoted to PROPERTIES. The most important ones are binding of small molecules, physical and optical sensors, catalysis, photocatalysis and electron/photon induced processes. In chapter 15 few closing remarks are made. 

Currently, two basic chemical approaches to the formation of macromolecular metal complexes (MMCs) are widely used. The first and most commonly used is based on the chemical binding of transition metal compoimds (MXJ with macroUgands... 

Unfortunately, the aforementioned problems have not been adequately discussed in literature, although there is considerable interest in the preparation of structurally homogeneous macromolecular metal complexes for catalysis, photochemistry, biological applications, etc. This chapter reports on the specificity of the processes for formation of macromolecular complexes through both routes polymerlike transformations and copolymerization of metal-containing monomers. In addition, the predictive potential of reactions and the ways of preventing some of them will be discussed. 

Unmodified poly(ethyleneimine) and poly(vinylpyrrolidinone) have also been used as polymeric ligands for complex formation with Rh(in), Pd(II), Ni(II), Pt(II) etc. aqueous solutions of these complexes catalyzed the hydrogenation of olefins, carbonyls, nitriles, aromatics etc. [94]. The products were separated by ultrafiltration while the water-soluble macromolecular catalysts were retained in the hydrogenation reactor. However, it is very likely, that during the preactivation with H2, nanosize metal particles were formed and the polymer-stabilized metal colloids [64,96] acted as catalysts in the hydrogenation of unsaturated substrates. 

Summary Recent achievements in two catalytic reactions, i.e., silylative coupling and cross-metathesis of alkenes and dienes with vinyl-silicon compounds, which resulted in new synthetic routes to organosilicon molecular and macromolecular compounds are presented. The silylative coupling, also called dehydrogenative or trans-silylation and silyl group transfer, is catalyzed by metal complexes which either contain or initiate the formation of M-H and M-Si bonds, where M = Ru, Rh, Co and Ir. Cross-metathesis, which was developed very recently, proceeds in the presence of metallacarbenes, mainly those of rathenium (e.g., Grabbs catalyst). 

The formation of type II metal-containing macromolecules obtained by the reaction of bi/multifunctional low molecular weight metal complexes with another bi/multi-functional ligand can be evaluated by usual rate constants, equilibrium and kinetics as known for polycondensation or polyaddition reactions in macromolecular chemistry. Increasing insolubility results easily in chain termination and formation oligomers. 

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