The present volume "Manganese" D 6 continues the description of the manganese com- plexes. The introduction on p. 1 shows the classes of complexes that have already been described in Chapters 1 through 29 in Volumes D1 to D 5. Complexes with Schiff bases and related compounds (e.g., hydrazones, semicarbazones, or thiosemicarbazones) are now described in Chapters 30 and 31 of this volume and complexes with carbazones, thiocarba- zones and formazans in Chapter 32. Complexes with Schiff bases play a central role in the development of coordination chemistry. The publications range from synthetic aspects to modern physicochemically or biochemically relevant investigations on these compounds. The huge number of studies results from the fact that these ligands may contain various donor atoms, in addition to the azomethine group, and thus can occur with variable denticities. About 1700 compounds derived from 808 different ligands are described in the present volume. Their arrangement is by ligand type and number of azomethine groups.

The present volume, "Manganese" D 5, continues the description of the manganese complexes. The arrangement of the complexes in these D volumes is based on the ligand type. The introduction, on p. 1, shows the classes of complexes, which have already been described in Chapters 1 to 21 in the Volumes D 1 (1979), D 2 (1980), D 3 (1982), and D 4 (1985). In Chapters 22 to 29 of this volume are treated complexes with amine-N-polycarboxylic acids, hydrazinecarboxylic acids, amides, hydrazides, derivatives of hydroxylamine (e.g., hydroxamic acids), oximes and nitroso compounds, azo compounds, and triazenes. A survey at the beginning of each of these sections gives information on the most characteristic features of the various complex types. Because of the complexometric relevance of the complexes with amine-N-polycarboxylic acids, there are many studies concerning the existence and the stability of the complexes in solution. Numerous X-ray investigations, reported for the complexes with urea or with amides and hydrazides of carboxylic acids, show the different structures of the compounds as a result of the varying bonding sites of the ligands. Complexes with hydrazides (e.g., with isonicotino hydrazide) are of special interest, due to their biological activity. Complexes with hydroxamic acids, oximes or azo compounds have been studied mostly in aqueous organic or pure organic solvents. The characteristic intense colors of many solutions are used for the analytical determination of manganese.