Addition anorganischer und organischer Nucleophile an den Vinyliden‐Liganden des Clusters FeCo 2 (CO) 9 (μ 3 ‐CCH 2 )

Addition of Inorganic and Organic Nucleophiles to the Vinylidene Ligand of the Cluster FeCo 2 (CO) 9 (μ 3 ‐CCH 2 ) The CCH 2 ligand of the cluster FeCo 2 (CO) 9 (μ 3 ‐CCH 2 ) ( 1 ) is electrophilic at the terminal C atom. Soft inorganic nucleophiles [Nu – PR 3 , (CH 3 ) 2 SO, CN − , SCN − ] are added to form the zwitterionic complexes FeCo 2 (CO) 9 (μ 3 ‐C–CH 2 –Nu) ( 4, 7, 8 ), as proved by the structure determination of FeCo 2 (CO) 9 (μ 3 ‐CCH 2 – PMe 3 ) ( 4a ). The products are of low thermal stability. Upon heating, the PR 3 derivatives rearrange to the CO substitution products FeCo 2 (CO) 8 (PR 3 )(μ 3 ‐CCH 2 ) ( 5, 6 ). C–C coupling is achieved by addition of malonic ester anion derivatives [X – CH – CO 2 Me] (XMeO 2 C, CN, Br). The anionic addition product for XMeO 2 C ( 10a ) can be protonated to form HFeCo 2 (CO) 9 [μ 3 CCH 2 – CH(COOMe) 2 ] ( 11 ) which liberates H 2 upon warming resulting in FeCo 2 (CO) 9 [μ 3 ‐CCH – CH(COOMe) 2 ] ( 12 ). Thus, a substitution of a vinylidene H atom has been performed by an HX addition/H 2 elimination sequence. Phosphorus ylides R 3 PCHX [XH, SiMe 3 , Cl, CHO, C(O)Ph, COOR] are also added with CC coupling to yield the complexes FeCo 2 (CO) 9 (μ 3 ‐CCH 2 – CHX – PR 3 ) ( 15, 16 ). The structure determination of the compound with XEtO 2 C and RPh ( 16c ) proves that these complexes differ from the complexes 4 just by insertion of one methylene unit.