CO Cleavage Promoted by Acetylide Addition to Vinyliminium Diiron Complexes

The vinyliminium complex [Fe 2 {μ‐η 1 :η 3 ‐C(Me)=C(Me)C=N(Me)(Xyl)}(μ‐CO)(CO)(Cp) 2 ][SO 3 CF 3 ] ( 1 ; Xyl = 2,6‐Me 2 C 6 H 3 ) reacts with LiC≡CR [R = C 6 H 4 Me = Tol, Ph, H, n Bu, SiMe 3 , C(Me)=CH 2 ] affording the amido‐functionalized allylidene complexes [Fe 2 {μ‐κ 1 (O):η 1 (C):η 3 (C)‐C(C≡CR)C(Me)C(Me)C(O)N(Me)(Xyl)}(μ‐CO)(Cp) 2 ] [R = C 6 H 4 Me = Tol, 2 ; R = Ph, 3 ; R = H, 4 ; R = n Bu, 5 ; R = SiMe 3 , 6 ; R = C(Me)=CH 2 , 7 ] in good yields. Labelling experiments with 13 CO‐enriched 1 indicate that formation of 2 – 7 occurs through cleavage of the carbon–oxygen bond of a coordinated CO ligand. The molecular structure of 2 has been determined by an X‐ray diffraction study. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)