Reaktionen von R2AlAlR2 (R  CH(SiMe3)2) mit Trimethylsilylazid — Insertion in die AlAl‐Bindung und Abbau zum trimeren Dialkylaluminiumazid

Abstract

AbstractReactions of R2AlAlR2 (R  CH(SiMe3)2) with Trimethylsilyl Azide — Insertion into the AlAl Bond and Formation of a Trimeric Dialkylaluminium AzideTetrakis[bis(trimethylsilyl)methyl]dialuminium(4) (1) reacts with trimethylsilyl azide under insertion of one nitrogen atom into the AlAl bond. As shown by NMR spectra and crystal structure the product contains three and four coordinated Al atoms due to the coordination of the α‐nitrogen atom of the azide group to one of the Al atoms. An electronically delocalized N3‐system is formed with a NN bond length of 132.0 pm and a bond order of 1.5 for both NN bonds. With an excess of trimethylsilyl azide further reaction is observed only under mild irradiation conditions with an exchange of the azide group between Si and Al and formation of Me6Si2 and the dialkylaluminium azide 3, which is better synthesized by the reaction of Me3SiN3 with ClAl[CH(SiMe3)2]2. The sterically highly shielded aluminium azide 3 is a trimer in the solid state showing a non‐planar 12‐membered Al3N9 heterocycle with short NN bonds (114 pm).