Mechanisms of Nitric Oxide Reactions Mediated by Biologically Relevant Metal Centers

Struct Bond (2014) 154: 99–136 DOI: 10.1007/430_2013_117 # Springer-Verlag Berlin Heidelberg 2013 Published online: 5 October 2013 Mechanisms of Nitric Oxide Reactions Mediated by Biologically Relevant Metal Centers Peter C. Ford, Jose Clayston Melo Pereira, and Katrina M. Miranda Abstract Here, we present an overview of mechanisms relevant to the formation and several key reactions of nitric oxide (nitrogen monoxide) complexes with biologically relevant metal centers. The focus will be largely on iron and copper complexes. We will discuss the applications of both thermal and photochemical methodologies for investigating such reactions quantitatively. Keywords Copper Heme models Hemes Iron Metalloproteins Nitric oxide Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Metal-Nitrosyl Bonding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . How Does the Coordinated Nitrosyl Affect the Metal Center? . . . . . . . . . . . . . . . . . . . . . . . . . . . The Formation and Decay of Metal Nitrosyls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Some General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Rates of NO Reactions with Hemes and Heme Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Mechanistic Studies of NO “On” and “Off” Reactions with Hemes and Heme Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Non-Heme Iron Complexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Other Metal Centers of Biological Interest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Reductive Nitrosylation and Other Reactions of Coordinated NO . . . . . . . . . . . . . . . . . . . . . . . . 5.1 Reactions of Iron(III) Nitrosyls with Nucleophiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Reduction of Copper(II) Complexes by NO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Protonation of Metal Nitrosyls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Reactions with Dioxygen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P.C. Ford ( * ) and J.C.M. Pereira Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106-9510, USA e-mail: ford@chem.ucsb.edu K.M. Miranda Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, USA e-mail: kmiranda@email.arizona.edu