Properties and Reactions of Coordinatively Unsaturated Organometallics

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The purpose of this project has been to investigate structures, electronic states, reactivities, and properties of coordinatively unsaturated organometallic cluster complexes. Studies under this project has revealed dependences of coordinative unsaturation of transition-metal cluster complexes on ligands, metal atoms, and oxidation states as follows:1. A coordinatively unsaturated dinuclear manganese complex was prepared by photo-decarnonylation of a dinuclear manganese carbonyl complex. X-ray structure determination of both of the starting and resulting complexes showed that the coordinative unsaturation is accompanied by an increase of the multiplicity of the metal-metal bond. Studies are carried out on associative equilibria of the unsaturated dinuclear complex with several selected ligand molecules. Changes in enthalpy and entropy for the equilibria have been evaluated.2. Crystal structure of a new dinuclear platinum(II) complex showed a linear chain arrangement of the metal atoms. … More The platinum complex showed a self-association equilibrium in solutions. These phenomena are anylysed in connection with the electronic structure of the complex. Oxidation of the complex induced an increase of the tendency of the self-association.3. ESR studies have showen that the electronic configuration of the Rh-Rh bond in dirhodium tetracarboxylates and their analogs are ligand dependent. The electronic interactions for the dependence were analyzed on the basis of ligand dependence of their oxidation potentials.4. Studies were carried out on molecular structure and electrochemical behavior of newly prepared cobalt-rhodium mixed trinuclear cluster complexes. When the number of rhodium atom is increased, the one-electron oxidation takes place at a more positive potential and the one-electron reduction occurs at a more negative potential.5. Electronic structure of chemisorption of dihydrogen on nickel surfaces were calculated with an abinitio SCF MO method and analyzed with the interacting-frontier orbital method. Less