MICHAEL T. POPE AND ACHIM MULLER Department of Chemistry, Georgetown University, Washington, DC 20057-2222, U.S.A.; Department of Chemistry, University of Bielefeld, D-4BOO Bielefeld 1, F.R.G. Polyoxometalates, from their discovery and early development in the final decades of the 19th century to their current significance in disciplines as diverse as chemistry, mathematics, and medicine, continue to display surprisingly novel structures, unexpected reactivities and applications, and to attract increasing attention worldwide. Most of the contributors to the present volume participated in the workshop held at the Center for Interdisciplinary Research at the University of Bielefeld, July 15-17, 1992. The choice of topics illustrates some of the variety of directions and fields in which polyoxometalates can play an important role. Although many of the leading polyoxometalate research groups are represented here, we regret that time constraints, financial limitations, and in some cases difficulties of communication did not allow us to include significant and imp- tant work from other groups outside Europe and North America. In the following we briefly review the current status of the field of po- oxometalates.

InhaltsangabePolyoxometalates: A Class of Compounds with Remarkable Topology.- A: Formation and Structure.- Equilibria of Polyoxometalates in Aqueous Solution.- Synthesis and Structural Chemistry of Novel Heteropolymolybdates and -tungstates.- Progress in Polytungstophosphate and -arsenate(V) Chemistry.- Crystal Structure Studies of Isopoly and Heteropoly Oxometalates. Structure of the Paradodecatungstate Molecule and Its Environment in Crystals.- Polyoxoanion-Supported Organometallic Complexes.- New Aspects of Non-Aqueous Polyoxometalate Chemistry.- Functionalization of Polyoxomolybdates: the Example of Nitrosyl Derivatives.- Polyoxoalkoxy Molybdenum and Vanadium Clusters.- Polyoxovanadates with Organic Ligands.- B: Spectroscopy and Magnetochemistry.- New Aspects of NMR Spectroscopy of Polyoxometalates.- Polyoxotungstates with Lone-Pair Assembling Atoms: Part 2: 183W NMR Structural Study of the Inorganic Cryptates [MAs4W40O140](28-n)- and [MSb9W21O86](19-n)-(Mn+ = Alkaline or Alkaline Earth Cation).- Blue Electron Distributions in Diamagnetic Reduced Heteropoly Tungstates. Insights Concerning Conduction Pathways and Spin Coupling Patterns. 183W NMR Chemical Shift Calculations.- Interactions between Delocalized and Localized Electrons in Heteropoly Blues Containing Paramagnetic Transition Metals. Magnetic Susceptibility and NMR Studies.- Polyoxovanadates: The Missing Link between Simple Paramagnets and Bulk Magnets?.- Molecular Magnetic Materials from Polyoxometalates.- The Use of Polyoxometalates in Charge Transfer Salts.- C: Applications-Catalysis and Biology.- Catalytic Chemistry of Solid Polyoxometalates and Their Industrial Applications.- Polyoxoanions in Homogeneous Catalysis: Polyoxoanion-Supported, Atomically-Dispersed Iridium, [(l,5-COD)Ir-P2W15Nb3O62]8-.- Palladium and Phosphomolybdovanadate Catalyzed Olefin Oxidation to Carbonyls.- Mixed Addenda Phosphomolybdovanadates as Catalysts for Oxidations Dioxygen and Hydrogen Peroxide.- Role of Vanadium in Oxidation Catalysis by Heteropolyanions.- Photocatalytic Processes by Polyoxometalates. Splitting of Water. The Role of Dioxygen.- Polyoxometalates for Molecular Devices: Antitumor Activity and Luminescence.- Polyoxometalates in Catalytic Selective Homogeneous Oxygenation and Anti-HIV Chemotherapy.- Of Therapy, Toxicity and Tungstates: The Anti-Retroviral Pharmacology of Polyoxometalates.- Polyoxometalates in AIDS Therapy.- Interactions of Oxovanadates and Selected Oxomolybdates with Proteins.