Preparation and Interconversion of Binuclear 2-Ferrazetine and Isomeric Ferrapyrrolinone Complexes

Chad A. Mirkin, Kuang Lieh Lu, Thomas E. Snead, Bruce A. Young, Gregory L. Geoffroy*, Arnold L. Rheingold, Brian S. Haggerty

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


The complex Fe2(μ-CH2)(CO)8 reacts with the phosphine imides R′3P=NR (R, R′ = Ph; R = But, R′ = Bun) to form a mixture of the 3-ferra-4-pyrrolin-2-one complexes Fe2(μ-CH=CHN(R)C{O})(CO)6 and the 2-ferrazetine complexes Fe2(μ-CH=CHNR)(CO)6. the latter complexes derive from the former by loss of CO, which is accelerated by heating (50 °C, 3 h) or by adding CO-labilizing agents (halides, [HB(s-Bu)3]). This reaction is reversed by photolysis of the 2-ferrazetine complexes under 1 atm of CO. However, when the 2-ferrazetine complexes are allowed to thermally react with CO, the isomeric 2-ferra-4-pyrrolin-3-one complexes Fe2(μ-C{O}CH=CHNR)(CO)6 are produced instead. These latter complexes have been found to add electrophiles (HBF4 and [Me3O]BF4) to the acyl oxygen to form the cationic complexes [Fe2{μ-C(OR)= (CHCH=NBut)}(C0)8]BF4 (R = H, Me). the 3-ferra-4-pyrrolin-2-one complexes also react with acid (HBF4) under 1 atm of CO to form the complexes [Fe2{μ-C(H)(CH=NHR)}(CO)8]BF4, which possess protonated μ21-azallylidene ligands. the dimethylcarbene complex Fe2(μ-CMe2)(CO)8 also reacts with (Bun)3P=NBut, but this reaction stops at the acyl complex Fe2(μ-CMe2)(CO)7(C{0}N(But)P(Bun)3) since this species cannot undergo the hydrogen migration needed to give entry to the ferrapyrrolinone and ferrazetine complexes. Mechanisms are proposed for these various transformations, and the following complexes have been crystallographically characterized: Fe2(μ-CH=CHNPhC{O})(CO)6, Fe2(μ-CH=CHNBut)(CO)6, Fe2(μ-C{O}CH=CHNPh)(CO)6, [Fe2(μ-CHCH=NHBut)(CO)8][CF3S03], and [Fe2(μ-C{OMe}=CHCH=NBut)(CO)8][BF4].

Original languageEnglish (US)
Pages (from-to)3800-3810
Number of pages11
JournalJournal of the American Chemical Society
Issue number10
StatePublished - May 1 1991

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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