Mehrfachbindungen zwischen Hauptgruppenelementen und übergangsmetallen. XCIII. Methyl- und Ethylrheniumoxide: Präparative und strukturchemische Aspekte

The dinuclear methylrhenium oxides (CH₃)₄Re₂O₄ (3a) and (CH₃)₆Re₂O₃ (4) are conveniently synthesized by means of organozinc, -titanium, and -aluminium reagents from the simple precursor compounds Re₂O₇, CH₃ReO₃, and (CH₃)₃SiOReO₃. The two diamagnetic d¹-d¹ systems (Re^VI) can be oxidized by means of amine oxides: the novel Re^VII-complex (CH₃)₄Re₂O₅ as the pyridine adduct 5 thus results from 3a and pyridine N-oxide and has been characterized by an X-ray diffraction study. By way of contrast, the dinuclear structure is split upon treatment of 4 with trimethylamine oxide, with (CH₃)₃ReO₂ (6) thus being formed. The novel ethyl derivative (C₂H₅)₄Re₂O₄) (3b), prepared from Re₂O₇ and diethylzink, has been characterized structurally (X-ray diffraction).