PHOSPHORANE IMINATO COMPLEXES OF TITANIUN - THE CRYSTAL-STRUCTURES OF [TICL2(NPPH(3))2] AND [TICL3(NPME(2)PH)(CH3CN)](2)

[TiCl2(NPPh(3))(2)] has been prepared by the reaction of [TiCl3(NPPh(3))] with excess Me(3)SiNPPh(3) in a melt at 220 degrees C, forming colourless crystals. [TiCl3(NPMe(2)Ph)(CH3CN)](2) is formed as yellow, moisture sensitive crystals from acetontrile solutions of [TiCl3(NPMe(2)Ph)](2), which on its part has been obtained by the reaction of TiCl4 with Me(3)SiNPMe(2)Ph. The complexes are characterized by IR spectroscopy and by crystal structure determinations. [TiCl2(NPPh(3))(2)]. Space group Fdd2, Z = 8, structure refinement with 2875 observed unique reflections, R = 0.039. Lattice dimensions at 19 degrees C: a = 2080.9, b = 3308.5, c = 973.6 pm. The compound forms monomeric molecules with bond lengths TiN of 179.0 pm and PN of 156.8 pm, which correspond with double bonds. The bond angle TiNP is 166.6 degrees. [TiCl3(NPMe(2)Ph)(CH3CN)](2). Space group P $($) over bar$$ 1, Z = 1, structure refinement with 2577 unique reflections, R = 0.039 for reflections with I > 2 sigma(I). Lattice dimensions at 20 degrees C: a = 856.6, b = 923.1, c = 1008.3 pm, alpha = 81.23 degrees, beta = 71.63 degrees, gamma = 81.41 degrees. The compound forms centrosymmetric, dimeric molecules, in which the titanium atoms are linked via chloro bridges TiCl2Ti with TiCl bond lengths of 243.9 and 270.3 pm. In trans-position to the longer TiCl bonds the nitrogen atoms of the phosphorane iminato groups are coordinated with bond lengths TiN of 173.9 pm and PN of 161.4 pm which again correspond with double bonds. The bond angle TiNP is 156.4 degrees.