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

The complexes [Fe-2{mu-CN(Me)R}(mu-CO)(NCMe)(CO)(Cp)(2)]SO3CF3 (R = Me, 2a; 2,6-Me2C6H3, 2b' CH2Ph 2c), easily obtained from the corresponding [Fe-2{mu-CN(Me)R}(mu-CO)(CO)(2)(Cp)(2)]SO3CF3 (1a-c) precursors, react with NBu4CN affording the cyano complexes [Fe-2{mu-CN(Me)R}(mu-CO)(CN)(CO)(Cp)(2)] (3a-c) by displacement of the MeCN ligand. The analogous reaction with NBu4Cl leads to the formation of [Fe-2{mu-CN(Me)R}(mu-CO)(Cl)(CO)(Cp)(2)] (4a-b). The mu-hydride complexes [Fe-2{mu-CN(Me)R}(mu-H)(CO)(2)(Cp)(2)] (5a-b) have been prepared by reaction of 1a-b with NaBH4. The corresponding diruthenium compound [Ru-2(mu-CNMe2)(mu-H)(CO)(2)(Cp)(2)] (6) has been similarly obtained from [Ru-2(mu-CNMe2)(mu-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 alpha-beta or cis-trans isomeric mixtures, are reported and discussed. (C) 2000 Elsevier Science S.A. All rights reserved.