Reaction Control of Dynamic Complexes

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Coordination bonds of organotransition metal complexes are characterized by the flexibility of metal-carbon, metal-hetero atom, and metal-metal bonds. The flexibility is represented by facile bond formation and cleavage, as well as change of molecular parameters such as electron population, bond length and bond angle, in both static and dynamic molecular frameworks caused by a small physical and chemical stimuli applied to the complexes. This project aims at development of new synthetic methodology and functional materials through a systematic investigation of the structure-reactivity relation in organotransition metal complexes.Llsomerization of allyl alcohol catalyzed by dinuclear ruthenium complexesDinuclear ruthenium complexes containing benzene ligand tethered by oxygen functional group were found to catalyze isomerization of allyl alcohols to the corresponding aldehydes and ketones. Key features of this catalysis are proposed to rely on facile coordination and dissociation of oxygen atoms of both substrates and the side arm of the benzene ligand. Specifically, the isomerization might have proceeded via coordination of allyloxo ligand, followed by β-H elimination and H shift to the terminal carbon of α, β-enone intermediate.2.Coupling of η^2-ketone and η^2-alkene on nickel promoted by Me_3AlCyclization of carbonyl group and alkene group on nickel forming an oxanickelacycle has been postulated to be a key step in some nickel catalyzed coupling reactions. In this study a well-characterized η^2-carbonyl-η^2-alkene complex of nickel(0) was isolated and its structure determined. Treatment of this complex with Me_3Al promoted oxidative cyclization of carbonyl-alkene groups to give 5-membered oxanickelacycle with Ni coordinated by electron-deficient methyl bridge with AL