Applications of Coordination Compounds

Coordination compounds are found in living systems and have many uses in the home, in industry, and in medicine. We describe a few examples here and in the Chemistry in Action essay on p. 976. 

The extraction of silver and gold by the formation of cyanide complexes (p. 922) and the purification of nickel (p. 892) by converting the metal to the gaseous compound Ni(CO)4 are typical examples of the use of coordination componnds in metallurgical processes. 

Earlier we mentioned that the chelating agent EDTA is used in the treatment of lead poisoning. Certain platinum-containing compounds can effectively inhibit the growth of cancerous cells. A specific case is discussed on p. 978. 

Although EDTA has a great afiOniiy for a laige number of metal ions (especially 2+ and 3+ ions), other chelates are more selective in binding. For example, dimethylglyoxime. 

Simplified structures of Uie porp ine molecule and the Fe -porphyrin complex. The dashed lines represent coordinate covalent bonds. 

In addition to its use in medicine and chemical analysis, EDTA is used as a food additive to sequester metal ions. EDTA sequesters copper, iron, and nickel ions that would otherwise catalyze the oxidation reactions that cause food to spoil. EDTA is a common preservative in a wide variety of consumer products. 

Chelation therapy works by the administration of a ligand, which binds to metal ions already in the body. Many drugs, including cisplatin Chapter 3, Applying What You ve Learned], are themselves coordination compounds in which the central metal ion binds to electron-rich sites (such as oxygen or sulfur atoms) in biological molecules. 

Most complex ions containing Co, Cr, and Pt ate kinetically inert. Because they exchange ligands very slowly, they ate easy to study in solution. As a result, our knowledge of the bonding, stmcture, and isomerism of coordination compounds has come largely from studies of these compounds. 

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Wilkinson s treatise on applications of coordination compounds includes a chapter that describes the use of formazan/tetrazolium systems... 

Application of coordination compounds in medicine, materials chemistry, and as catalysts are mentioned and are cross-referenced to a fuller discussion in Volume 9. Comment is made on application of complexes in nanotechnology, and on the molecular modeling of complexes. The material cannot be totally comprehensive because of space limitations, but is selected in such a way to give the most effective review of discoveries and new interpretations. 

Some of the important types of coordination compounds occur in biological systems (for example, heme and chlorophyll). There are also significant applications of coordination compounds that involve their use as catalysts. The formation of coordination compounds provides the basis for several techniques in analytical chemistry. Because of the relevance of this area, an understanding of the basic theories and principles of coordination chemistry is essential for work in many related fields of chemistry. In the next few chapters, an introduction will be given to the basic principles of the chemistry of coordination compounds. 

The applications of coordination compounds in catalysis that have been shown are by no means the only important cases. In fact, there are numerous reactions in which homogeneous catalysis forms the basis for a great deal of chemistry. From the examples shown, it should be apparent that this is a vast and rapidly developing field. It is also one that is important from an economic standpoint. Although the basic principles have been described in this chapter, the literature related to catalysis is extensive. For further details and more comprehensive reviews of the literature, consult the references listed. 

The Synthesis, Reactions, Properties Applications of Coordination Compounds... 

The coverage has been limited to the applications of coordination compounds or of the coordination chemistry of relatively soluble ligands and metal species. Numerous chemical agents in photographic systems function by means of adsorption on silver halide grains and silver metal surfaces. Such chemical interactions lie outside the confines of coordination chemistry defined for this work and have not been discussed. 

Latent images or faint images in silver metal or other materials can be amplified by redox chemistries other than metal deposition. Several dye-forming redox chemistries have been discovered in which metal complexes serve as catalysts, catalyst precursors or one of the redox partners. The applications of coordination compounds in physical development and image amplification systems are therefore quite broad and diverse. 

Coordination compounds have become very usable in medicine [361-364]. In this respect, use of metal complexes (mostly those of lanthanides) as diagnostic [365-367] and anticancer [368-370] media should be specially emphasized. Among the last complexes, the aminoplatinum-containing compounds play an important role, so the structural study of platinum complexes as a model of nucleobases [371] is a topic of renewed interest. The new issue of Comprehensive Coordination Chemistry II [372] contains a wide description of nanoparticles (vols. 6 and 7), biocoordination chemistry (vol. 8), and other aspects of application of coordination compounds. 

C. A. McAuliffe, in Comprehensive Coordination Chem-istry-The Synthesis, Reactions, Properties and Applications of Coordination Compounds , eds. Sir G. Wilkinson, R. D. Guillard, and J. A. McCleverty, Pergamon Press, New York, 1987, Vol. 3, Chap. 28. 

G. Wilkinson, ed., Comprehensive Coordination Chemistry The Synthesis, Reactions, Properties and Applications of Coordination Compounds in 7 Volumes. Pergamon, Oxford, 1987. 

Microwave radiation is a widely used tool in the synthesis and chemical application of coordination compounds. Problems of control and reproducibility encountered when using domestic... 

The chemistries of scandium and yttrium are often reported together (although yttrium is also often grouped with the lanthanides) so in this section they will be discussed together. Reference, where appropriate, will be made to the first volume in this series, Comprehensive Coordination Chemistry The Synthesis, Reactions, Properties and Applications of Coordination Compounds (CCC, 1987). Volume 3 of CCC (1987) contained a chapter entitled Scandium, Yttrium and the Lanthanides and this chapter is designed to follow part of that chapter. The articles reviewed will cover the period 1982-2001 although earlier work may be cited. Volume 2 of CCC (1987), devoted to ligands, will also be referred to in this chapter. 

APPLICATION OF COORDINATION COMPOUNDS ANCHORED ONTO CARBON 289... 

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