Adventures in the coordination chemistry of di-2-pyridyl ketone and related ligands: From high-spin molecules and single-molecule magnets to coordination polymers, and from structural aesthetics to an exciting new reactivity chemistry of coordinated ligands

The coordination chemistry of di-2-pyridyl ketone and related ligands is reviewed. An outline of the variety of such ligands is presented. References are given to methods for the synthesis of ligands that are not available on the market. The aclivation of the carbonyl group(s) of somo of the ligands towards further reactions sooms to bo an emergent area of synthetic inorganic chemistry. The coordination chemistry of each ligand with metals is briefly described. Emphasis is placed on structural features and physical properties (mainly magnetic) of the resulting metal clusters and coordination polymers. The structural diversity of the complexes stems from the ability of the deprotonated diol- or hemiketal-typeligands to adopt a variety of bridging coordination modes depending on the number of carbonyl groups, the nature of the extra donor groups in the molecule and on the reaction conditions. Employment of a second organic or inorganic ligand in this chemistry gives an extraordinary structural flexibility in the resulting mixed-ligand systems. The initial use of 1,1′-carbonyldiimidazole and 1,1′-oxalyldiimidazole in copper(II) chemistry, which leads to unprecedented coordination polymers containing alcoholysis and/or hydrolysis "fragments" of the ligands, is also illustrated.