| Abstract: | Phosphorane Iminato Complexes of Titanium(IV) and Titanium(III). The Crystal Structures of TiCl2(OMe)(NPPh3)]2, TiBr2(NPPh3)]2 · 3C7H8, and Ph3PNH2]Br · CH2Cl2 TiCl3(NPPh3) reacts with a solution of methyllithium in diethyl ether in the presence of lithiummethylate forming yellow TiCl2(OMe)(NPPh3)]2. On reaction with benzyl magnesium bromide TiCl3(NPPh3) in diethyl ether is converted into green TiBr2(NPPh3)]2 under reduction and ligand exchange. TiBr2(NPPh3)]2 crystallizes from toluene with three molecules C7H8. Ph3PNH2]Br · CH2Cl2 originates as a side product of this reaction. The products are characterized by their i.r. spectra and by crystal structure analyses. TiCl2(OMe)(NPPh3)]2 . Space group P1 , Z = 2, structure solution with 2909 independent reflections, R = 0.063. Lattice dimensions at 20°C: a = 1005.1, b = 1044.5, c = 1068.6 pm, α = 66.98°, β = 89.35°, γ = 80.24°. The compound forms centrosymmetric dimeric molecules with μ2-OMe bridges and five-fold coordinated titanium atoms. The (NPPh3?) ligand is terminally connected with a Ti = N distance of 174.8 pm and with a TiNP bond angle of 165.3°. TiBr2(NPPh3)]2 · 3 C7H8 . Space group P1 , Z = 2, structure solution with 5548 independent reflections, R = 0.053. Lattice dimensions at ?70°C: a = 983.3, b = 1162.7, c = 1376.5 pm, α = 100.53°, β = 110.30°, γ = 105.24°. The compound forms centrosymmetric dimeric molecules with μ2-NPPh3 bridges and tetrahedral coordination at the titanium atoms. With 195.9 pm the Ti–N bonds correspond with single bonds. The Ti …? Ti distance of 260.0 pm is exceptionally short. Ph3PNH2]Br · CH2Cl2 . Space group P1 , Z = 1, structure solution with 3091 independent reflections, R = 0.049. Lattice dimensions at 20°C: a = 909.4, b = 1004.4, c = 1158.5 pm, α = 108.09°, β = 94.67°, γ = 91.92°. The bromide ions are bonded to a one-dimensional infinite network via hydrogen bridge bonds of the cation and of the dichloromethane. |
