Reactions of acetonitrile di-iron μ-aminocarbyne complexes; synthesis and structure of [Fe2(μ-CNMe2)(μ-H)(CO)2(Cp)2]

The complexes [Fe2{μ-CN(Me)R}(μ-CO)(NCMe)(CO)(Cp)2]SO3CF3 (R=Me, 2a; 2,6-Me2C6H3, 2b; CH2Ph, 2c), easily obtained from the corresponding [Fe2{μ-CN(Me)R}(μ-CO)(CO)2(Cp)2]SO3CF3 (1a–c) precursors, react with NBu4CN affording the cyano complexes [Fe2{μ-CN(Me)R}(μ-CO)(CN)(CO)(Cp)2] (3a–c) by displacement of the MeCN ligand. The analogous reaction with NBu4Cl leads to the formation of [Fe2{μ-CN(Me)R}(μ-CO)(Cl)(CO)(Cp)2] (4a–b). The μ-hydride complexes [Fe2{μ-CN(Me)R}(μ-H)(CO)2(Cp)2] (5a–b) have been prepared by reaction of 1a–b with NaBH4. The corresponding diruthenium compound [Ru2(μ-CNMe2)(μ-H)(CO)2(Cp)2] (6) has been similarly obtained from [Ru2(μ-CNMe2)(μ-CO)(NCMe)(CO)(Cp)2]SO3CF3. The X-ray molecular structure of 5a is that expected for cis isomers of this family of compounds. It shows a chiral conformation of the C5H5 ligands and the crystals are a conglomerate of enantiomeric individuals. NMR spectra of the various compounds, which are indicative of the presence of α–β or cis–trans isomeric mixtures, are reported and discussed.