Intriguing Reactivity of a 1,2-Dihydrodialumane Towards Organic Azides – From a Terminal Diazido–Dialumane to Pendulum-Clock-Like Azide Bridging
Wang X., Traeger F., Ligorio RF., Graw N., Herbst-Irmer R., Krawczuk A., Fischer M., Stalke D.
The reactivity of dihydro-dialane with organic azides is described. Treatment of the hybrid ligand-based dialane [(DNI{H}Al)2] (I) (DNI = [3,3-dimethyl-2-2-methyl-2-(2,6-diisopropylaniline)ethenyl]-3H-indolenine) with TMSN3 (TMS = trimethylsilyl) at room temperature gives the first diazido-dialane [(DNI{N3}Al)2] (1). The transformation from here to a more stable aluminium-tetrazole [DNIAl(NTMS)2N2] (2) is established. The reaction of other RN3 gives [(DNI{H}Al)2(κ2-N3R)] (R = Benzyl in 3 and 1-Adamantyl in 4) with the azide in a μ-bridging position between two aluminium atoms. Using 1H NOESY/EXSY NMR spectroscopy, a positional exchange of the two TMS groups (2) via rotation of the tetrazole unit is observed. In contrast, compound 3 exhibits a pendulum-clock-like dynamic, with Nα oscillating between the two aluminium atoms in solution. The reaction of dialane I with DippN3 (Dipp = 2,6-iPr2-C6H3) gives the dialuminium amine [{DNI(H)Al}2(μ-NDipp)] (5).