Interactions of nitric oxide and organic nitroso compounds with metalloporphyrins and heme

The chemistry of nitric oxide (NO) has taken on new dimensions since the discovery, about a decade ago, of a myriad of biological events that NO participates in. Many of the foundations of metal-NO chemistry were laid out earlier by inorganic chemists and biochemists investigating the structures and electronic properties of the heme-NO moiety or its model compounds. Certainly, the persistent work over the last three decades by chemists working with metal nitrosyls has paid off. Current areas of research in heme-NO chemistry include (i) how the NO group approaches and binds to the metal center (or how it dissociates from the metal center); (ii) the ground state and excited state geometries of the metal-NOfragment; (iii) effects of the trans axial ligands on NO orientation and/or dissociation; and (iv) N-N bond formation from NO molecules catalyzed by heme groups.