Mehrfachbindungen zwischen hauptgruppenelementen und übergangsmetallen. LXVII. Zur kenntnis der "metallsäure" methyl(trioxo)rhenium(VII): adduktbildung mit amin-basen und aromaten. die struktur des anilin-komplexes CH₃ReO₃·H₂NC₆H₅

The organometallic oxide methyl(trioxo)rhenium(VII), CH₃ReO₃ (1), a Lewis acidic 14e system, forms adducts of composition [CH₃ReO₃] · L (2) with a large number of nitrogen bases. The aniline derivative CH₃ReO₃ · H₂NC₆H₅ (2b) shows an uncommon structure in the crystalline state (single crystal X-ray diffraction study, -60°C), in that the two-dimensional infinite architecture is defined by hydrogen bridges of varying lengths between the isomeric units A and B. The compound 1 combines with bidentate nitrogen ligands (L⋯L) to give compounds of composition [CH₃ReO₃] · (L⋯L) (3) or [CH₃ReO₃]₂ · (L⋯L) (4), where the stoichiometry of the product is primarily influenced by the pattern and degree of substitution at the nitrogen atoms. As a rule two primary amine functions entail N,N′-chelate complexes of type 3, while tertiary amines exclusively form 2 : 1-adducts of type 4. Most of these adducts show dynamic behaviour in solution, detectable by means of ¹H and ¹⁷O NMR spectroscopy. If isolation of the adducts is possible, practically quantitative yields are achieved.