Degree Type
Dissertation
Date of Award
2004
Degree Name
Doctor of Philosophy
Department
Chemistry
First Advisor
Robert J. Angelici
Abstract
This dissertation describes three investigations of the dinuclear ruthenium complex, (eta5-C5H3)2(SiMe 2)2)Ru2(CO)4: (1) its use as a catalyst for the hydroamination of alkynes by a new mechanism, (2) its reactions with H2 to give new ruthenium clusters containing bridging hydride ligands, and (3) the determination of thermodynamic and kinetic acidities of two related complexes, (eta5-C5H 3)2(SiMe2)2Ru2(CO) 3P(OR)3H+BF4- (R= Me, Ph).;A fundamentally new mechanism for alkyne hydroamination catalyzed by the ruthenium complex, (eta5-C5H3) 2(SiMe2)2Ru2(CO)3(C 2H4)H+BF4-, has been proposed. Many of the intermediates in the catalytic cycle have been isolated and/or characterized spectroscopically and found to react according to the proposed mechanism. The catalyst activity is terminated as a result of the isomerization of a bridging alkyne ligand in a key intermediate in the catalytic cycle.;The butterfly cluster, (eta5-C5H3) 2(SiMe2)22Ru4(CO) 3H4, and the square planar cluster, (eta5-C 5H3)2(SiMe2)22Ru 4(CO)4H4, have been isolated from the photochemical reaction of H2 with the doubly-linked dicyclopentadienyl complex, (eta5-C5H3)2(SiMe 2)2Ru2(CO)4, in benzene. Wavelength-dependent photolysis studies suggest that the first step in the reaction of (eta 5-C5H3)2(SiMe2)2 )Ru2(CO)4 with H2 involves metal-metal bond cleavage.;The reaction of the protonated phosphite complexes, (eta5-C 5H3)2(SiMe2)2Ru2(CO) 3P(OR)3H+BF4- (R= Me, Ph), with tertiary amines (DABCO, 4-methylmorpholine, NEt3, N(n-Bu)3) results in clean deprotonation of the metal-metal bond by the amine. Equilibrium measurements show that the P(OPh) 3 complex is more acidic than the P(OMe)3 complex. The rates of deprotonation of the phosphite complexes have been determined, and follow the rate law: Rate = k1[complex] + k 2[amine][complex]. Comparisons of the k2 rate constants reveal that the reactions are much more sensitive to the steric properties of the amine and metal complex than to electronic factors.
DOI
https://doi.org/10.31274/rtd-180813-11686
Publisher
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu
Copyright Owner
David Peter Klein
Copyright Date
2004
Language
en
Proquest ID
AAI3145699
File Format
application/pdf
File Size
97 pages
Recommended Citation
Klein, David Peter, "Chemistry of ruthenium complexes incorporating the doubly-linked bis(dimethylsilylcyclopentadienyl) ligand " (2004). Retrospective Theses and Dissertations. 1138.
https://lib.dr.iastate.edu/rtd/1138
