Synthesis,Structure, and Reactivity of Diazene Adducts: Isolation of iso‐Diazene Stabilized as a Borane Adduct |
| |
| Authors: | Dipl‐Chem Fabian Reiß Prof Dr Axel Schulz Dr Alexander Villinger |
| |
| Affiliation: | 1. Institut für Chemie, Abteilung Anorganische Chemie, Universit?t Rostock, Albert‐Einstein‐Strasse 3a, 18059 Rostock (Germany);2. Leibniz‐Institut für Katalyse e.V. an der Universit?t Rostock, Albert‐Einstein‐Strasse 29a, 18059 Rostock (Germany) |
| |
| Abstract: | This work describes the synthesis and full characterization of a series of GaCl3 and B(C6F5)3 adducts of diazenes R1?N?N?R2 (R1=R2=Me3Si, Ph; R1=Me3Si, R2=Ph). Trans‐Ph?N?N?Ph forms a stable adduct with GaCl3, whereas no adduct, but instead a frustrated Lewis acid–base pair is formed with B(C6F5)3. The cis‐Ph?N?N?Ph ? B(C6F5)3 adduct could only be isolated when UV light was used, which triggers the isomerization from trans‐ to cis‐Ph?N?N?Ph, which provides more space for the bulky borane. Treatment of trans‐Ph?N?N?SiMe3 with GaCl3 led to the expected trans‐Ph?N?N?SiMe3 ? GaCl3 adduct but the reaction with B(C6F5)3 triggered a 1,2‐Me3Si shift, which resulted in the formation of a highly labile iso‐diazene, Me3Si(Ph)N?N; stabilized as a B(C6F5)3 adduct. Trans‐Me3Si?N?N?SiMe3 forms a labile cis‐Me3Si?N?N?SiMe3 ? B(C6F5)3 adduct, which isomerizes to give the transient iso‐diazene species (Me3Si)2N?N ? B(C6F5)3 upon heating. Both iso‐diazene species insert easily into one B?C bond of B(C6F5)3 to afford hydrazinoboranes. All new compounds were fully characterized by means of X‐ray crystallography, vibrational spectroscopy, CHN analysis, and NMR spectroscopy. All compounds were further investigated by DFT and the bonding situation was assessed by natural bond orbital (NBO) analysis. |
| |
| Keywords: | boron diazenes frustrated Lewis pairs gallium hydrazinoboranes |
|
|
