Synthesis of a Novel Hybrid Ligand System Incorporating Classic Moieties through Acylation of 2,3,3-Trimethylindolenine

In main group chemistry, the BDI ligand ([HC(C(Me)N(R))₂]), more commonly known as NacNac, has proved indispensable over the last two decades. Within this work, we are introducing the hybrid NacNac-akin ligand 3,3-dimethyl-2-[2-methyl-2-(2,6-diisopropyl-aniline)ethenyl]-3H-indolenine (DNI). On the basis of this novel ligand, alkali metal complexes [DNI(M¹)] [M¹=Li (3(OEt₂)), Na (4(THF)₃), and K (5(THF)₃)] have been synthesized by facile deprotonation of the ligand's backbone. The reaction of DNI with AlH₃ ⋅ NMe₂Et led to the aluminium dihydride compound [DNI-AlH₂] (6) in excellent yield (90 %). Further synthesis of [DNI-AlI₂] (7), which is seen as a potential precursor for the aluminium(I) complex, was realized in the presence of 1.0 equiv. iodine with 6. All products 2–7 were completely characterized by 2D-NMR, mass spectrometry, elemental analysis and SC-XRD. Density functional theory calculations were performed to provide better understanding of their bonding characteristics and electronic structures.