Phosphaniminato-Komplexe des Titans. Die Kristallstrukturen von [TiCl2(NPPh3)2] und [TiCl3(NPMe2Ph)(CH3CN)]2

Phosphorane Iminato Complexes of Titanium. The Crystal Structures of TiCl₂(NPPh₃)₂] and TiCl₃(NPMe₂Ph)(CH₃CN)]₂ TiCl₂(NPPh₃)₂] has been prepared by the reaction of TiCl₃(NPPh₃)] with excess Me₃SiNPPh₃ in a melt at 220°C, forming colourless crystals. TiCl₃(NPMe₂Ph)(CH₃CN)]₂ is formed as yellow, moisture sensitive crystals from acetontrile solutions of TiCl₃(NPMe₂Ph)]₂, which on its part has been obtained by the reaction of TiCl₄ with Me₃SiNPMe₂Ph. The complexes are characterized by IR spectroscopy and by crystal structure determinations. TiCl₂(NPPh₃)₂] . Space group Fdd2, Z = 8, structure refinement with 2875 observed unique reflections, R = 0.039. Lattice dimensions at 19°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°. TiCl₃(NPMe₂Ph)(CH₃CN)]₂ . Space group P1 , Z = 1, structure refinement with 2577 unique reflections, R = 0.039 for reflections with I > 2σ(I). Lattice dimensions at 20°C: a = 856.6, b = 923.1, c = 1008.3 pm, α = 81.23°, β = 71.63°, γ = 81.41°. 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°.