Photochemical reactions of metal nitrosyl complexes. Mechanisms of NO reactions with biologically relevant metal centers

摘要

The discoveries that nitric oxide (a.k.a. nitrogen monoxide) serves important roles in mammalianbioregulation and immunology have stimulated intense interest in the chemistry and biochemistry of NOand derivatives such as metal nitrosyl complexes. Also of interest are strategies to deliver NO to biologicaltargets on demand. One such strategy would be to employ a precursor which displays relatively low thermalreactivity but is photochemically active to release NO. This proposition led us to investigate laser flashand continuous photolysis kinetics of nitrosyl complexes such as the Roussin's iron-sulfur-nitrosyl clusteranionsFe2S2(NO)42?andFe4S3(NO)7?and several ruthenium salen and porphyrin nitrosyls. These includestudies using metal-nitrosyl photochemistry as a vehicle for delivering NO to hypoxic cell cultures in order tosensitizeγ-radiation damage. Also studied were the rates and mechanisms of NO “on” reactions with modelwater soluble heme compounds, the ferriheme protein met-myoglobin and various ruthenium complexesusing ns laser flash photolysis techniques. An overview of these studies is presented.