A study of molybdenum complexes supported by alpha-diimines and amine-bis(phenols) and their applications towards oxygen atom transfer reactions
Metal centered oxygen atom transfer (OAT) has many industrial and biological applications. Reactions such as epoxidation of olefins, oxidation of sulfides to sulfoxides and sulfones, and deoxodehydration of polyols are just a few of these important reactions. The objective of this research is to investigate the ability to synthesize molybdenum centers that contain diimine ligands, which can act as electron reservoirs. The second chapter of this dissertation reports the synthesis of novel molybdenum dicarbonyl complexes supported by two diimine ligands. While a great deal of literature has been dedicated to establishing a relationship between the bond lengths of the diimine ligands and oxidation state of the metal, the systems we have synthesized do not follow this trend. X-ray diffraction studies of a variety of complexes would indicate that the ligand bond lengths should correspond to a Mo(II) complex. However, careful Mo K- edge XAS studies indicate that the complexes are best described as Mo(0). Also reported is a geometry change invoked by an electrochemical process. Through FTIR- spectroelectrochemical investigation of the complexes, we are able to assign this as a cis -to-trans isomerization of the carbonyl groups. The second portion of this dissertation focuses on the synthesis and reactivity of molybdenum dioxo complexes supported by amine-bis(phenolate) complexes. These complexes show promising reactivity toward sulfoxidation and deoxodehydration reactions. With low catalyst loading, we observe complete conversion of hydrobenzoin to a specific ratio of 2:1 benzaldehye to trans-stilbene. This ratio has implications towards the mechanism of the reaction.
Abu-Omar, Purdue University.
Molecular chemistry|Inorganic chemistry
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