Lanthanide Hydride Reduction Chemistry Including New Routes to Lanthanide Metallocene Dinitrogen Complexes.

摘要

This dissertation describes new types of ligand-based reactivity for organometallic compounds of yttrium and the lanthanides as well as the synthesis of a new structural type in organouranium chemistry. Ligand elimination reactions with bimetallic yttrium and lanthanide hydride and alkyl complexes provide redox behavior from compounds with redox inactive metals. New methods of synthesis have allowed access to unsolvated dinitrogen complexes of the smallest lanthanides. Manipulating the steric bulk of ligands has allowed synthesis of the first example of a bent uranocene complex.;In Chapter 1 a new way of bringing the reductive chemistry of divalent lanthanide metals to lanthanides without a readily accessible divalent oxidation state is described. The [(C5Me5)2LnH] 2 (Ln = La, Sm, Y) complexes were found to eliminate H2 in the presence of a reducible substrate and provide 2e- capable of reducing the substrate. This type of elimination has not been seen before with the lanthanides or yttrium. The first example of a metalated cyclooctatetraenyl ligand, (C8H7)3-, was also synthesized, in (C5Me5)Y(mu-eta8:eta 1-C8H7)Y(C5Me5)2 during this study.;Chapter 2 expands the range of ligand based reductions in redox inactive complexes by examining elimination of Ln-C and Ln-H bonds using a (C 5Me5)2Y(mu-H)(mu-eta1:eta 5-CH2C5Me4)Y(C5Me 5) precursor. The Ln-C and Ln-H moieties react to form a C-H bond and deliver 2e- to reduce a substrate.;Chapter 3 describes the extension of the LnZ2Z'/K method of synthesizing lanthanide dinitrogen complexes using Z'= H-. This variation required non-coordinating solvents and generated [(C5 Me5)2Y]2(mu-eta2:eta2-N 2) as a solvent-free complex.;In Chapter 4 the synthetic routes of solvent-free dinitrogen complexes were expanded with the discovery that [(C5Me5) 2Ln][(mu-Ph)2BPh2] precursors could be reduced to form [(C5Me5)2Ln]2(mu-eta 2:eta2-N2) complexes. These LnZ2 Z'/K routes were the first that did not require THF.;Chapter 5 describes the use of a bulky, substituted cyclooctatetraene ligand, [C8H6(SiPh3)2] 2-, to synthesize the first uranocene derivative with non-planar rings. [C8H6(SiPh3)2]2U, was synthesized from UCl4 and Li2[C8H6(SiPh 3)2] and contains a 167.7° (ring centroid)-U-(ring centroid) angle.;Chapter 6 lays out ideas for future work that have come from the research described in this dissertation.