Types of Reaction Undergone by Coordinated Ligands and the Factors Influencing the Change in Their Reactivity

The influence of the following factors on the reactivity of coordinated ligands (chiefly nitrogen-containing ligands) is examined: 1) the nature of the metal ion; 2) displacement of the electrons of the ligand to the central ion; 3) change in the stability of the complexes formed in the reaction relative to that of the original complexes; 4) the charge of the ionic complexes; 5) the influence of π-dative bonding by one ligand to the central atom on the reactivity of another ligand in the same complex; 6) stabilisation of one of the tautomeric forms of a ligand as a result of complex formation with metal ions; and 7) stabilisation of the deprotonated form of a ligand by complex formation. Examples of the masking of individual functional groups by complex formation and the manifestation of new chemical properties of the ligand as a result of coordination are examined. It is shown that in a number of instances the metal ion can be regarded as a matrix on which the synthesis of an organic molecule takes place. Reactions involving "insertion" into a metal–ligand bond are discussed. The bibliography contains 93 references.