Acyclic and Cyclic Silylaminohydrazines

The reaction of H2N-NH2 with ClSiMe2N(SiMe3)2 in a molar ratio 1 : 2 gave the bis(silylamino) hydrazine [HNSiMe2-N(SiMe3)2]2 (1). Compound 1 forms a monomeric dilithium salt with BuLi. From n-hexane (Me3Si-NSiMe2-NLiSiMe3)2 (2) crystallizes while from THF [Me3Si-NSiMe2- NLi(THF)SiMe3]2 (3) precipitates. Compounds 2 and 3 are formed from 1 via a silyl group migration. In the rearranged salts, the silyl groups are bonded at the hydrazino nitrogen atoms. Hydrolysis of 2 led to the formation of (Me3Si-N-SiMe2-NHSiMe3)2 (4) which is a structural isomer of 1. Ring closure occurs in reactions of 2 or 3 with F3B ・ OEt2 or SiF4. The seven-membered rings (Me3Si- N-SiMe2-NSiMe3)2BF (5) and (Me3Si-NSiMe2-NSiMe3)2SiF2, (6) were isolated as the products. The crystal structures of 2, 3 and 5 have been determined.