Synthesis, coordination chemistry, and reactivity of functionalized phosphines: Toward water-soluble macrocyclic phosphine complexes

Macrocyclic phosphine compounds have long been sought as ligands for transition metal complexes because of their strong binding properties. Despite considerable effort in this field, no general methods for synthesizing phosphine macrocycles or their complexes have been developed. This dissertation describes attempts to synthesize an iron complex with a water-soluble macrocyclic tetraphosphine ligand for use in separating nitrogen from natural gas. Chapter I reviews previous syntheses of macrocyclic phosphine ligands and their complexes, focusing on ligand synthesis, coordination chemistry, and demetallation of the complexes.;Chapter II reports on the synthesis of water-soluble secondary bidentate phosphine ligands, their coordination chemistry with iron(II), and attempts to use these complexes as templates for forming a macrocyclic iron-phosphine complex by reactions with carbon electrophiles.;Over the course of treating these iron complexes with various carbon electrophiles, an interesting reaction between bromomaleic anhydride and proton sponge was discovered. Chapter III explores the product, 4-maleicanhydrido-1,8-bis-(dimethylamino)naphthalene (MAPS). Due to its conjugated donor-acceptor network, which is disrupted upon protonation, MAPS acts as a colorimetric version of a proton sponge. The attachment of MAPS to amine-functionalized solid supports, forming solid-supported proton sponge reagents, is also described.;Chapter IV discusses the synthesis of an iron(II) complex of the water-soluble phosphine 1,2-bis(di(hydroxymethyl)phosphino)ethane (DHMPE). Although unbound hydroxymethylphosphines commonly react with NH-functional amines via the phosphorus Mannich reaction, this and other complexes of DHMPE do not undergo this reaction. Further investigation with hydroxymethylphosphine-boranes suggests that the currently-accepted mechanism of the phosphorus Mannich reaction is incorrect, and an alternate mechanism is proposed.;Chapter V discusses the synthesis and functionalization of copper(I) complexes of water-soluble phosphines. Unlike the complexes described in Chapter I, these complexes readily react with alpha,o-dihalides or di(acyl chloride)s, forming complexes whose mass spectra correspond to those with macrocyclic phosphine ligands. Unlike most macrocyclic tetraphosphine complexes, these complexes can be demetallated by treatment with sulfide. Finally, a new synthesis of water-soluble macrocycles, based on lessons learned during the course of these investigations, is proposed.;This dissertation includes previously published and unpublished co-authored material.