Photochemical & Related Thermal Mechanisms of Transition Metal Complexes

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

The Inorganic, Bioinorganic, and Organometallic Chemistry Program provides continued support for photochemical research by Dr. Peter C. Ford,Chemistry Department, University of California, Santa Barbara. The photochemical mechanisms of nitric oxide (NO) generation as well as the dynamics of thermal reactions between NO and metal centers of bioinorganic interest will be studied. Flash and continuous photolysis of various mononuclear metal nitrosyl and metal nitrito complexes will be conducted, placing particular emphasis on the molecular design of compounds that may serve as precursors for the photochemical delivery of NO to desired targets on demand. "Antennas" constructed of porphyrins or other chromophores that absorb red light will be coupled to the precursors to allow for low-energy excitation of the metal nitrosyl part of the compound by single photon or two photon absorption mechanisms. The chemistry will also be extended to systems that generate nitrosyl hydride (HNO) and nitroxyl anion (NO-), two species that also may have biological importance. When light is absorbed by a molecule, the energy that the molecule acquires sometimes initiates a chemical reaction. In this case, a precursor molecule disintegrates to release nitric oxide (NO) plus a metal-containing byproduct. Because NO is a bioregulator of the cardiovascular system as well as participating in immune responses, the controlled release of this molecule has many potential medical benefits. This fundamental study may lead to new strategies for photodynamic therapy and other uses of nitric oxide. Several graduate students will be trained in this important new area of inorganic chemistry.