Umsilylierungsreaktionen an Silylphosphiniminen

New functional silylated phosphine imines are prepared from N-(trimethylsilyl)triorganophosphinimines a and polyfunctional halosilanes. This reaction is very simple and gives high yields. The resulting silicon compounds are not in every case stable in the expected form. The siliconhalogen bond energy, the donor strength of the nitrogen atom, the acceptor properties of the silicon atom and steric effects are the factors which decide whether the products are stable monomers with covalent character, or dimers with an ionic principle of structure, containing a dicationic four-membered ring system. The transsilylation mechanism is discussed.