Bond activation and catalysis by nontrigonal tricoordinate and tetracoordinate phosphorus compounds

Abstract

Molecular distortion has a profound impact on the electronic structure and reactivity of molecules. This dissertation describes studies on E-H bond activation and catalytic reactivity of [sigma]³- and [sigma]⁴ -phosphorus compounds with distorted nontrigonal structures. Specifically, a rare example of N-H oxidative addition to a planar, C2v-symmetric P(III) center is described in Chapter 2. The kinetics and computational studies implicate a noncanonical, phosphorus-based electrophilic pathway for this transformation. As detailed in Chapter 3, a Cs-symmetric phosphorous triamide and its P-N cooperative reactivity are presented. B-H activation and catalytic imine hydroboration are achieved via the combination of the electrophilic phosphorus center and the basic anilide ligand moiety of this Cs-symmetric phosphorus compound. Finally, Chapter 4 extends the study of distorted phosphorus compounds to [sigma]⁴ -phosphorus molecules. Iminophosphoranes bearing constrained ligand platforms are synthesized and their distortion-induced B-H, B-O and Si-H bond activation reactivity are presented. This research provides insight into the influence of molecular symmetry on the reactivity of [sigma]³- and [sigma]⁴-phosphorus compounds and represents an initial step toward the discovery of new chemistry in other distorted phosphorus molecules.