Reactivity of Yttrium Carboxylates Toward Alkylaluminum Hydrides.

Yttrocene-carboxylate complex [Cp*₂Y(OOCAr^Me)] (Cp*=C₅Me₅, Ar^Me=C₆H₂Me₃-2,4,6) was synthesized as a spectroscopically versatile model system for investigating the reactivity of alkylaluminum hydrides towards rare-earth-metal carboxylates. Equimolar reactions with bis-neosilylaluminum hydride and dimethylaluminum hydride gave adduct complexes of the general formula [Cp*₂Y(μ-OOCAr^Me)(μ-H)AlR₂] (R=CH₂SiMe₃, Me). The use of an excess of the respective aluminum hydride led to the formation of product mixtures, from which the yttrium-aluminum-hydride complex [{Cp*₂Y(μ-H)AlMe₂(μ-H)AlMe₂(μ-CH₃)}₂] could be isolated, which features a 12-membered-ring structure. The adduct complexes [Cp*₂Y(μ-OOCAr^Me)(μ-H)AlR₂] display identical ¹ J(Y,H) coupling constants of 24.5 Hz for the bridging hydrido ligands and similar ⁸⁹Y NMR shifts of δ=−88.1 ppm (R=CH₂SiMe₃) and δ=−86.3 ppm (R=Me) in the ⁸⁹Y DEPT45 NMR experiments. [ABSTRACT FROM AUTHOR]