Abstract
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.