Lewis Acidic Behavior of Antimony: Applications in Catalysis and Anion Binding
Abstract
Over the past decade, the chemistry of σ-accepting or Z-type ligands based on main group elements has drawn renewed attention because of the realization that their interaction with a transition metal (M) could be used to control the reactivity of the metal center. In this dissertation, I will describe my efforts to modulate the reactivity of platinum complexes in which the Z-type ligand is an antimony unit and more specifically a halostiborane unit. The work described here shows that these complexes are prone to antimony-centered anion abstraction making the coordinated platinum center more oxidized and thus more electrophilic. Another strategy involves the use of weakly coordinating anion which, in the presence of a basic substrate, readily dissociate from the dinuclear core, resulting once again in an increased electrophilic character at the platinum center. These changes favorably impact the activity of the complexes as catalysts for enyne cycloisomerization reactions and hydroarylation reactions.
The results obtained in these studies underscore the favorable role of these anion abstraction reactions which notably increase the carbophilic reactivity of the platinum center. The strong Lewis acidity of antimony can also become an asset in the area of anion binding. Distiboranes designed to chelate small anions have shown advantageous anion chelating properties, including in protic media. To further improve these properties, this dissertation has explored the synthesis and properties of distiboranes based on the electron deficient perfluoro-ortho-phenylene backbone. Experimental and computational results indicate that perfluorination of the ortho-phenylene backbone affords fluoride anion chelators whose fluoride ion affinity exceeds that of its non-fluorinated analogues.
Citation
You, Di (2019). Lewis Acidic Behavior of Antimony: Applications in Catalysis and Anion Binding. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /189237.