CO-induced ring-slippage reactions of molybdenocene and tungstenocene carbonyl complexes. Electrochemical and elevated-pressure infrared evidence for an electron-transfer catalysis
Abstract Infrared studies at a CO pressure of 120 bar show (η 5 -C 5 H 5 ) 2 W(CO) to be completely resistant to an excess of CO in the absence of oxidants, but cyclovoltammetric measurements with this complex and with (η 3 -C 5 H 5 )(η 5 -C 5 H 5 )W(CO) 2 in THF solution at 0°C indicate that the ring-slipped dicarbonyl complex is catalytically generated by a one-electron oxidation of the tungstenocene monocarbonyl under CO at ambient pressure. Similar results are found for the reaction of (η 5 -C 5 H 5 ) 2 Mo(CO) with CO.
Intermediates in the formation of dicyclopentadienyltungsten dicarbonyl : role of a dicyclopentadienyltungsten carbonyl chloride action
Abstract Dicyclopentadienylcarbonyl chloride cations of tungsten and molybdenum, (C 5 H 5 ) 2 M(CO)Cl + (M W, Mo) are obtained from a reaction of the corresponding dichlorides with AlCl 3 and CO. Reduction of (C 5 H 5 ) 2 W(CO)Cl + in the presence of CO gives the dicarbonyl complex (C 5 H 5 ) 2 W(CO) 2 . The corresponding molybdenum complex was not obtained under analogous reaction conditions.
The application of 13C and 1H NMR spectroscopy to the investigation of the dinitrogen fixation process in the system (η-C5H5)2TiCl2-Mg
Abstract The N 2 reduction reaction in the system (η-C 5 H 5 ) 2 TiCl 2 -Mg in tetrahydrofuran was examined. The 13 C and 1 H NMR results as well as the chemical properties of the products formed revealed that the reaction yielded a mixture of compounds in which the titanium atom was bonded both to the μ-(η 5 : η 5 -fulvalene) ligand and to the cyclopentadienyl ligands. In this system dinitrogen undergoes reduction to N 3− , which then forms M 3 N bridges (M = Ti, Mg). The nitride nitrogen may readily be oxidized to imide nitride N −1 , which may react further, e.g. with carbon monoxide to produce isocyanates, or, with excess oxidizing agent N 2 . THF in this system undergoes polymerisation. In addition, a −OC 4 H 9 alkoxy group is formed which makes the substitution of the cyclopentadienyl group bonded to the titanium atoms possible.