The interaction of RR'N-PCl2 (1) with LiNR"SiMe3 gives monomeric phospha(IH)-azenes RR'N-P=N-R"; R = R"=i-C3H7, R'= (CH3)3C (3a); R=i-C3H7,R'=R" = (CH3)3C (3b); R = i-C3H7, R' = (CH3)3C, R"=(CH3)3Si (3c) as distillable liquids. 3a adds PCl3 with formation of RR'N-PCl-NR-PCl2, R = i-C3H7, R'=(CH3)3C (6).
Thermolysis of the silylated diaminochloro-phosphine (1) yields the cis-and trans-diazadi-phosphetidines (2). These isomers show a great difference in the melting points and 31P-NMR spectra. Hindered P-N rotation is observed for trans-2b.
Diazadistibetidines of the type (XSbNCR3)2, with X = Cl, Br and R = CH3, have been synthesized by reacting SbX3 with LiN(CR3)SiR3-The initial reaction products R3C(R3Si)NSbX2 (1) split off R3SiX with formation of the four-membered rings 2. The silylated bis(amino)-halostibines 3 do not eliminate R3SiX even at 200 °C.