A Linear Ru-Tl-Ru Complex Obtained from Halide Abstraction: An Example of Metal-Dative Bonding

The simple abstraction of chloride ion from [RuCl(CO)2(η-C5H5)] using [TlBF4] proved problematic, unexpectedly giving a new complex containing linear Ru–Tl–Ru. The complex, [{Ru(CO)2(η-C5H5)}2(μ-Tl)(F–BF2–F)]∞, was polymeric, as determined by a single-crystal X-ray diffraction experiment, in which the thallium centres are bridged by the anions. In an effort to compare the nature of the Tl–Ru bonds, an additional complex was prepared by the reaction of Tl3+ ions with [Ru(CO)2(η-C5H5)]–. The resulting neutral complex, [{Ru(CO)2(η-C5H5)}3(μ-Tl)], was also structurally characterised. Quantum chemical calculations of [{Ru(CO)2(η-C5H5)}2(μ-Tl)][BF4] suggest that the Tl–Ru bond has ionic character with integrated atomic charges showing that the metal–metal bonding is best represented as Ru0–TlI–Ru0. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)