# Intriguing Reactivity of a 1,2‐Dihydrodialumane Towards Organic Azides – From a Terminal Diazido–Dialumane to Pendulum‐Clock‐Like Azide Bridging

## TL;DR

This paper explores how a dialane reacts with azides to form new aluminum compounds, including a unique azide complex and dynamic molecular motion observed via NMR.

## Contribution

The first example of a low oxidation state aluminum azide complex and the discovery of pendulum-clock-like molecular dynamics in solution.

## Key findings

- The first diazido-dialane [(DNI{N3}Al)2] was synthesized from dihydro-dialane and TMSN3.
- Dynamic behavior of the tetrazole unit and pendulum-clock-like motion of the azide were observed via NMR.
- A new aluminum amine complex [{DNI(H)Al}2(μ-NDipp)] was formed using DippN3.

## Abstract

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).

The reaction of a dihydro‐dialane supported by a hybrid ligand (DNI) with organic azides yields structurally diverse aluminium species, including the first example of low oxidation state aluminium azide complex, a diazido‐dialane, along with an aluminium‐tetrazole, and azide alumination. Spectroscopic studies reveal dynamic behaviour in solution, featuring a pendulum‐clock‐like motion of the benzyl azide and Nα oscillation within the complex.