Einführung eines terminalen Halogenoliganden in diorgano-verbrücke Dirhenium- und Molybdän-Rhenium-Komplexanionen in Gegenwart eines Amidinkations |
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Authors: | H-J Haupt G Disse U Flrke |
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Institution: | H.-J. Haupt,G. Disse,U. Flörke |
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Abstract: | Insertion of a Terminal Halogeno Ligand into Diorgano-bridged Dirhenium and Rhenium-Molybdenum Complex Anions in the Presence of an Amidin Cation and the Isomerization Processes The equimolar reaction of in situ generated anion Anions Re2(μ-PCy2)(CO)8? (Re? Re) in the presence of a steric expansive amidine cation DBUH+ with bromine and iodine in tetrahydrofuran solution gave the two isomers Re2(PCy2)(CO)8X (Re? Re) and Re2(μ-PCy2)(μ-X)(CO)8 (X = Br, I), of which the isomer with a terminal X ligand as major product was formed under maintenance of the Re? Re bond. The monotropic isomerization process of Re2(μ-PCy2)(CO)8I runs thermically relative slowly, but more rapid in photochemical and electrochemical processes. The analogeous reaction of the heterometallic anion ReMo(η5-C5H5)(μ-PPh2)(CO)6? with iodine delivers opposite to the former reaction mainly the bridged isomer ReMo(η5-C5H5)(μ-PPh2μ-I)(CO)6 besides ReMo(η5-C5H5)(μ-PPh2)(CO)6I. The obtained complexes were characterized by means of v(CO) and 31P NMR spectroscopic measurements. Single-crystal analyses led to the subsequent metal—metal bond lengths: Re? Re of 308.0(1) pm in Re2(μ-PCy2)(CO)8Br and Re? Mo of 313.6(1) pm in ReMo(η5-C5H5)(μ-PPh2)(CO)6I. |
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Keywords: | Dirhenium complex anion rheniummolybdenum complex anion NMR data crystal structure |
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