Neue Cyclophosphazene mit Metallen der III. Hauptgruppe als Ringbausteine / New Cyclophosphazenes with Metals of Main Group III as Building Blocks

Acylic silylated phosphazenes of the type HN(PR 2 NSiMe 3 ) 2 (1) react quantitatively with molecules MMe 3 (M = Al, Ga, In) under ring formation and CH 4 evolution. The ring compounds N(PPh 2 NSiMe 3 ) 2 AlMe 2 (2 a) and N(PPh 2 NSiMe 3 ) 2 InMe 2 (4 a) have been investiga­ ted by X-ray structure determination. 2a and 4a crystallize in the space groups P 1̄ and P 3 1 , respectively; they show different conformations regarding the cyclohexane framework. NMR spectroscopy of the nuclei in the chelating phosphazene ligand indicates decreasing Lewis acidity of the metal containing fragments in the series AlMe 2 ≥ GaMe 2 > InMe 2 .