CRYSTAL-STRUCTURES OF THE SILYLATED PHOSP HANIMINES ME(3)SINPPH(3) AND ME(3)SINPPH(2)-C2H4-PPH(2)NSIME(3)

The crystal structures of two silylated phosphanimines have been deter mined. Me(3)SiNPPh(3): Space group P $$($) over bar 1, Z = 2, structur e refinement with 2907 observed unique reflections with F-o > 5 sigma( F-o), R = 0.052. Lattice dimensions at 19 degrees C: a = 876.6(1), b = 1125.8(1), c = 1151.2(1) pm, alpha = 61.71(1)degrees, beta = 88.08(1) degrees, gamma = 57.18(1)degrees. The compound forms monomeric molecul es with a SiNP bond angle of 140.2 degrees and bond lengths PN of 154. 2 pm and SiN of 168.6 pm which correspond with PN double and SiN singl e bonds. Me(3)SiNPPh(2)-C2H4-PPh(2)NSiMe(3): Space group P3(1), Z = 3, structure refinement with 4251 independent reflections, R = 0.061 for 3587 reflections with I > 2 sigma(I). Lattice dimensions at -80 degre es C: a = b = 1591.4(1), c = 1165.8(1) pm. The compound forms monomeri c molecules with a cis-conformation of the PNSiMe(3) groups. Bond angl es and bond lengths (average) are SiNP = 140.8 degrees, PN = 153.8 pm, SiN = 165.6 pm.