Date of Award
Doctor of Philosophy (PhD)
George G. Stanley
The tetraphosphine ligand, Et$\sb2$P(CH$\sb2)\sb2$P(Ph)CH$\sb2$P(Ph)(CH$\sb2)\sb2$PEt$\sb2 ,$ et,ph-P4, was designed to be a binucleating ligand for use in bimetallic hydroformylation catalysis. This ligand can be tailored for both electronic and steric factors at the internal and external phosphorus atoms. It is hoped that through careful tuning of this ligand, the rate and selectivity of our bimetallic catalyst can be optimized for various substrates. Modification of the original ligand may also lead us to a better understanding of the mechanism involved in the catalytic cycle. My goal has been to replace the phenyl substituents on the internal phosphorus atoms with various alkyl groups. These modifications have fallen into two broad categories: the P(TMS)$\sb3$ and the Cl$\sb2$PCH$\sb2$PCl$\sb2$ synthetic pathways. While investigating the chemistry of Cl$\sb2$PCH$\sb2$PCl$\sb2$, a new highly synthetic method for functionalizing halogenated phosphines based on RZnCl reagents was discovered. This has opened up new routes to previously unattainable compounds, and provided a far simpler path to existing organophosphines. It is this zinc based chemistry combined with the Cl$\sb2$PCH$\sb2$PCl$\sb2$ derivatives which holds the most promise, especially for future stereoselective synthesis.
Koch, Howard Frederick III, "The Synthesis of Novel Phosphine-Modified Ligands for Use in Bimetallic Hydroformylation." (1997). LSU Historical Dissertations and Theses. 6543.