UC Irvine

The non-ionic, super-basic phosphorus of proazaphosphatranes has been extensively studied as organic catalysts and stoichiometric bases. They are commercially available and have been used as ligands for palladium cross-coupling reactions. Despite this utility, a fundamental understanding of proazaphosphatranes as ligands in coordination chemistry and transition metal catalysis has not been thoroughly investigated. Herein, modification of proazaphosphatrane compounds with pyridine, thiophene, and furan groups expand its chelating ability beyond its monodentate frame. The coordination chemistry of modified and unmodified proazaphosphatranes with various transition metal ions is explored, specifically investigating their electron donating properties and transannular interactions. Additionally, the reactivity of these transition metal azaphosphatrane complexes with small molecules (CO2, H2, and O2) is examined. A multidisciplinary approach is employed to study these transition metal azaphosphatrane complexes, founded on the design and synthesis of organic ligands and the development of metal complexes. Reactivity studies and inorganic, organic, and analytical characterization methods are carried out.

Chapter 1 describes the electronic and steric parameters of azaphosphatranes using the Tolman electronic parameters and cone angle.

Chapter 2 describes the modification of azaphosphatranes incorporating pyridine, thiophene and furan substituents.

Chapter 3 describes the experimental and computational investigation of the varying degree of transannular interaction in tris(2-pyridylmethyl)azaphosphatrane (TPAP) when coordinated to transition metals ions in different oxidation states.

Chapter 4 describes the attempted reactivity of transition metal complexes of TPAP with small molecules such as H2, O2, and CO2.