Formation and fate of iron-carbene complexes in reactions between a diazoalkane and iron-porphyrins: relevance to the mechanism of formation of N-substituted hemes in cytochrome P-450-dependent oxidation of sydnones

Abstract

Reaction of the diazocompound PhCH 2 CHN 2 with Fe(TpClPP=tetra-p-chlorophenylporphyrin)(Cl) at -30 o C and under argon led to a bridged carbene complex Fe III -CH(CH 2 Ph)-N(TpClPP)(Cl) (1) with a PhCH 2 CH moiety inserted between the iron and a pyrrole nitrogen atom. The visible and 1 H NMR spectra of complex 1 were very similar to those of the previously described Fe(III)-porphyrin complex with a vinylidene moiety (C=CAr 2 ) inserted into an Fe-N porphyrin bond, suggesting that 1 was also an intermediate spin (S=3/2) Fe(III) complex