Electrochemical and Chemical Investigations of Various Substituted Porphyrins, Chlorins and Porphyrazines

In this dissertation, by studying the electrochemistry and spectroelectrochemistry of three types of macrocycles: β-substituted, meso-substituted and/or fused porphyrins, chlorins and porphyrazines derivatives in a variety of non-aqueous media, the substituent, macrocycle, metal center, solvent condition, temperature and supporting electrolyte effects on the electrochemical and chemical behavior of these three types of macrocycles are investigated. Electrochemically or chemically synthesized products are also detected with different added anions, bases, or acids. Here are the key findings described in this dissertation: the electrochemically and chemically driven interconversion between the Ni(II) hydroxyphenylporphyrin and a reduced porphodimethene or oxidized porphyrin-like product, porpho-5,15-bis-paraquinone methide is seen; up to four facile reversible ring-centered reductions generating chlorin tetraanions are observed for the difused chlorins for the first time; strong hydrogen bonded dimers which exhibit mutiple reductions due to electronic communication between the two porphyrin -ring systems are observed; by changing the size of π-ring systems, adding electron withdrawing/donating substituents or ligating metal centers with different ligands, the redox potentials can be tuned accordingly.