Structure of Metal Complexes Containing Arenediazonium Ions as Ligands

1 Structure of Metal Complexes Containing Arenediazonium Ions as Ligands 

This chapter demonstrates that this statement is applicable to diazo compounds. Therefore, the reader should not be surprised to find here two sections on diazo and diazonium compounds as ligands in metal complexes and, in the volume on aromatic diazo chemistry (Chapt. 11), a discussion of host-guest complexation chemistry. 

It appears appropriate to include complexes with arenediazonium ions as ligands in the present volume and not in that on aromatic diazo chemistry because here these complexes can be discussed in the context of the corresponding aliphatic compounds (Sect. 10.3) and of the addition products of dinitrogen-to-metal complexes (Sect. 3.3). 

Interactions between transition metals and arenediazonium ions were already known in the early history of diazo chemistry. Since the discoveries of Sandmeyer (1884), Pschorr (1896), Meerwein et al. (1939), and others, various metal-catalyzed replacements of the diazonio group by other substituents became important synthetic methods in organic chemistry. We have discussed these reactions in several sections of our first book (Zollinger, 1994, Chapts. 8 and 10). 

Very little work was carried out, however, on the structure and properties of the primary addition products of transition metals on diazonium ions before organometallic chemistry started to grow strongly in the 1950 s. As briefly mentioned in Section 1.1, the first isolated and well characterized transition metal complex con- 

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