Preparation of coordination compounds
This chapter reviews the most common methods by which coordination compounds are prepared. However, current research is almost invariably aimed at producing the unusual and exotic, not the common. So, a contemporary research journal would describe methods rather less simple than most of those covered here. A flavour of the current has therefore been included, although the reader is unlikely to meet some of the compounds outside the research laboratory. In the reactions described in this chapter, there are two important variables—coordination number and oxidation number (the latter is often called the valence state). In principle, either may increase, decrease or remain unchanged in a reaction, and the reader may find it helpful to classify the preparative methods described according to changes in these two numbers. In practice it is not always possible to be certain of either without more information than that contained within a chemical equation or chemical formula. A ligand which is potentially tridentate may, for example, act as a bidentate ligand and so the coordination number differs from that expected. Similarly, is the complex ion [Co(NH3)5NO]2+ a complex of cobalt(II) or one of cobalt(III)? It depends on whether you believe that the NO is better represented as NO˙ (where, in the complex, the odd electron is paired with a cobalt electron) or as NO-. This problem of formal valence states will reappear later in this chapter and again in Chapter 6.
KeywordsCoordination Compound Substitution Reaction Preparative Method Trans Effect Triflic Acid
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