Cationic Boron Formazanate Complexes

Benjamin D. Katzman, The University of Western Ontario

Abstract

This thesis describes the synthesis and characterization of various three- and four-coordinate cationic and dicationic boron complexes supported by formazanate ([R₁-N-N=C(Ph)-N=N-R₅]⁻ ligands. The first chapter provides a review of various three-coordinate and cationic boron complexes and related applications. Chapter two examines the effect of several variations (i.e., charge, coordination number and boron-bound substituents) on the electronic structure of cationic boron formazanate complexes. Absorption spectroscopy measurements reveal that the wavelengths, intensities, and type of the first electronic transitions in cationic boron complexes can be modulated by these structural variations. Chapter three exploits the electron deficiency of a borenium cation supported by a N₂O₂^– formazanate ligand. Excellent Lewis acidity is demonstrated using the Gutmann-Beckett method. Further, a drastic decrease in the LUMO energy is observed upon introduction of cationic boron, compared to related neutral complexes. Together, this work demonstrates the utility of these cationic boron formazanates in the design of molecular materials.