A monomeric aluminum hydride complex bearing substituted pyrrolyl ligands, AlH[C4H3N(CH2NMe2)2]2 (1), was synthesized and structurally characterized. To further confirm the presence of AI-H bonds, the compound AlD[C4H3N(CH 2NMe2)-2]2 ([D]l) was synthesized by reacting LiAID4 with [C4H4N(CH2NMe 2)-2]. Compound 1 and [D]1 react with phenyl isothiocyanate yielding Al[C4H3N(CH2NMe2)-2] 2[η3-SCHNPh] (2) and Al[C4H 3N(CH2NMe2)-2]2[η-SCDNPh] ([D]2) by insertion. The reactions of 1 with 9-fluorenone and benzophenone generated the unusual aluminum alkoxide complexes 3 and 4, respectively, through intramolecular proton abstraction and C-C coupling. A mechanistic study shows that 9-fluorenone coordinates to [D]l and releases one equivalent of HD followed by C-C coupling and hydride transfer to yield the final product. Reduction of benzil with 1 affords aluminum enediolate complex 5 in moderate yield. Mechanistjfc^tudies also showed that the benzil was inserted into the aluminum hydride bond of [D]l through hydroalumination followed by proton transfer to generate the final product [D]S. All new complexes have been characterized by 'H and 13CNMR spectroscopy and X-ray crystallography.
All Science Journal Classification (ASJC) codes