Investigation of ruthenium salen nitro and nitrosyl complexes as photochemical nitric oxide precursors.

摘要

Nitric oxide is a key biological messenger in mammalian functions such as vasodilation, neurotransmission, and immune response. While nitric oxide is essential to life, numerous disease states have been attributed to the over- and under-production of this small molecule. Nitric oxide has been demonstrated to act as a gamma-radiation sensitizer with potential for a dual role in photodynamic cancer therapy. Interest in our group has concentrated on development of thermally stable metal nitrosyl complexes that photochemically generate nitric oxide, as well as understanding the fundamental interactions of transition metals with nitrogen oxides.;The aim of this dissertation is to describe the synthesis and characterization of ruthenium salen nitro and nitrosyl complexes to be used as photochemical nitric oxide precursors. Two stable ruthenium(III) salen nitro complexes, Ru(salen)(PPh3)(NO2) and Ru(salen(NO2) 2)(PPh3)(NO2), have been synthesized and characterized. An unexpected nitration of the aromatic rings on the salen ligand was observed for Ru(salen(NO2)2)(PPh3)(NO2) and a possible mechanism for this nitration is discussed.;Ruthenium salen nitrosyl complexes are thermally stable and ruthenium complexes have the added benefit of tending to aggregate in tumor cells. However, with regard to potential biomedical applications, more studies under more physiological conditions including aqueous media are needed. The synthesis and characterization of two water soluble salen ligands, Disodium [N,N'-ethylenebis(salicylideneimine)-5-sulfonate (salen-SO3), and [N,N'-bis(salicylidene)ethylenediamine-5-carboxylic acid] (salen-COOH) are described as well as the photochemical behavior of the water soluble ruthenium complex, [Ru(salen)(NO)(OH2)]SbF 6, in solutions of different pH.