METAL ATOM CHEMISTRY: SYNTHESIS, ISOLATION AND REACTIONS OF COORDINATIVELY UNSATURATED ORGANOMETALLIC COMPLEXES; ORGANOMETALLIC COMPLEXES CONTAINING BOTH SIGMA AND PI BONDS.

摘要

The metal atom technique has been shown to be a very versitile synthetic tool. The synthesis of non-ligand stabilized organometallic intermediates can be greatly enhanced. The power of the technique is perhaps based in the ability to prepare organometallic species in a very simple state. "Coordinatively unsaturated" organometallic intermediates can be prepared at low temperatures under inert conditions. Interactions with ligands are greatly reduced so that the species can be more easily examined. Species of this type have been proposed as active intermediates in a variety of homogeneous catalysis reactions. The synthesis of these species not only lends insight into catalytic mechanisms, but also expands the synthetic scope of the organometallic chemist. The synthesis of many complexes that could be made by conventional techniques may now be possible. This is exemplified by the synthesis of a wide series of pentafluorophenylpalladium complexes.;Sulfides (SPh(,2), SEt(,2), SMe(,2)), amines NH(,3), NH(,2)Et, NHEt(,2), pyridine), triethylphosphine and triphenylarsine react with bromopentafluorophenylpalladium(II) to form bisligand adducts. Bidentate ligands (2,2'-bipyridine, 1,5-cyclooctadiene) react to form cis adducts. Iodotrifluoromethylpalladium(II) reacts with pyridine to form iodotrifluoromethylbibyridinepalladium(II).;The extension of the metal atom technique to cobalt and nickel led to the preparation of novel complexes containing both (sigma) and (pi) bonds. h('6)-Arenebis(pentafluorophenyl)cobalt(II) and nickel(II) were prepared through the trideposition of the arenes and bromopentafluorobenzene with cobalt and nickel vapor, respectively. The complexes were found to be homogeneous hydrogenation catalysts for arenes at room temperature. The complexes were also found to be susceptible to arene exchange. Kinetic studies of the exchange reaction between h('6)-mesitylenebis(pentafluorophenyl)nickel(II) with d('8)-toluene and h('6)-(d('8)-toluene)bis(pentafluorophenyl)nickel(II) with mesitylene indicate that the exchange is first order for all components.;This dissertation is an example for the extensive research areas that are accessible via the metal atom technique.