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Incorporating Weakly-Coordinating Carborane Anions into Cationic Half-Sandwich
Ruthenium Electrophilic Complexes Chemistry
Anna S. Larsen
Department of Chemistry, Ithaca College, Ithaca, NY 14850
The main goal of our research proposal is development of the
reactive pro-catalytic and catalytic ruthenium-based systems with
carborane counterion. The optimization of the synthetic conditions
for the ruthenium carborane complexes leads us in search of the
new protonating agents. In addition to the ether and toluene based
protonation agents ([H Ln]+ [carborane]-, where L is a solvent of
choice ), we completed per-methylation of the carborane cage to
yield CB11Me12 and H-CB11Me11 anions via reaction with
methyl triflate. We subsequently synthesized the ether and toluene
acids with it. Currently we are working on the protonation
reactions using these new reagents with the ruthenium Cp*(NO)
systems. Per-methylation of the carborane cage results in vastly
improved solubility of the organometallic compounds. Currently
we are working on optimization of the crystallization conditions for
the ruthenium products.
Ruthenium ditriflate analog of the carborane
complexes oxidizes alcohols to yield
aldehydes (or ketones). We continued the
kinetic and thermodynamic variable
temperature NMR experiments on this
system. We have also characterized
structurally by single crystal X-ray
diffraction methods two products relevant to
this reaction (in collaboration with Phillip
Coppens group in SUNY Buffalo). Complex
1 is a model intermediate for initial alcohol
coordination step, -the chelate stabilized
ethylene glycol complex, and complex 2 is
an organometallic product of ruthenium
center reduction, - the ruthenium-ruthenium
double bond dimer. Both structures were
Ethyleneglycole
reported in Acta Crystallographica
publications this year.
Complex (1)
Ruthenium-ruthenium double bond
dimer with bridging nitrosyls (2)