The divergent reactivity of β-diketiminato aluminium hydrides with organophosphoryl compounds

The reactions of LAlH₂ (L = HC(CMeNAr)₂, Ar = 2,6-ⁱPr₂C₆H₃) (1) with diphenylphosphane oxide [Ph₂P(O)H], diphenylphosphinamide [Ph₂P(O)NH₂], and diaryl/alkyl phosphane [(RO)₂P(O)H (R = Ph, or ⁱPr)] afford their corresponding compounds with compositions LAl(H)OP(Ph)₂ (2), LAl[OP(Ph)₂]₂ (3), LAl{[N(H)P(O)(Ph)₂][OP(Ph)₂]} (4), LAl(OⁱPr)₂ (5), and LAl(OPh)₂ (6), respectively. These reactions probably undergo a process of dehydrogenation coupling, deaminating dehydrogenation coupling, or chain-breaking coupling. It is noteworthy to mention that the reaction of compound 1 with 2 equiv. of Ph₂P(O)NH₂ results in 4 and its isomer 4a, where both the complexes exhibit different coordination towards the aluminium centre. The structure of 4a is very rare, where the aluminium centre connects with a nacnac ligand as well as with N and O to form a six-membered and a four-membered ring, respectively. All the compounds were well characterized by multinuclear NMR spectroscopy, elementary analysis, and single-crystal X-ray diffraction.