Diiron Azamonothiolates via Scission of Dithiadiazacyclooctanes by Iron Carbonyls.

The reaction of Fe(CO) with the dithiadiazacyclooctanes [SCHN(R)CH] affords Fe[SCHN(Me)CH](CO) (R = Me, Bn). The methyl derivative was characterized crystallographically (Fe-Fe = 2.5702(5) Å). Its low symmetry is verified by variable temperature C NMR spectroscopy which revealed that the turnstile rotation of the S(CH)Fe and S(NMe)Fe centers are subject to very different energy barriers. Although resists protonation, it readily undergoes substitution by tertiary phosphines, first at the S(CH)Fe(CO) center, as verified crystallographically for Fe[SCHN(Me)CH](CO)(PPh). Substitution by the chelating diphosphine dppe (PhPCHCHPPh) gave Fe[SCHN(Me)CH](CO)(dppe), resulting from substitution at both the S(CH)Fe(CO) and S(NMe)Fe(CO) sites.