Nitric Oxide Insertion into a Metalloporphyrin–Carbon Bond

High Resolution Image Download MS PowerPoint Slide Nitric oxide (NO) insertion into a metalloporphyrin rhodium–carbon bond is observed when crystals of (TPP)Rh(C 6 H 4 Cl)(CH 2 Cl 2 ) x (TPP = tetraphenylporphyrinato dianion) are exposed to NO gas over a two week period. The NO-inserted product was identified by X-ray crystallography as (TPP)Rh(ONC 6 H 4 Cl- o )(CH 2 Cl 2 ) 0.5 ·(TPP)Rh(C 6 H 4 Cl- p / m )(CH 2 Cl 2 ) 0.5, in which NO inserted selectively into the ortho -Cl aryl isomer but not into the para -/ meta -Cl aryl isomers. Density functional theory calculations predict a higher reactivity for the ortho -Cl isomer and thus provide a rationale for the preferred NO insertion into the potentially more reactive ortho -Cl isomer under our reaction conditions. Whereas NO insertion reactions are well-known for coordination–organometallic compounds, this result represents the first such NO insertion into a metalloporphyrin metal–carbon bond for any metal.