Thermal decomposition of (Pentamethylcyclopentadienyl)titanium(IV) complexes containing dialkylamido ligands -: X-ray structure of [{η5:η2-C5Me4CH2CH2N(Me)CN(C6H3Me2)}TiCl2]

The new organometallic binuclear complexes [{Cp*Ti(NEt2)}(2)(mu-NEt)(2)] (1), [(Cp*Ti)(2)(NMe2)(NHMe2)(mu-NMe)(mu-NCH2)] (2), and [(Cp*TiCl)(2)(mu-NMe)(2)] (3) have been obtained by heating the dialkylamido derivatives [Cp*Ti(NR2)(n)Cl3-n] (R = Et, n = 3; R = Me, n = 2, 3) (Cp* = eta(5)-C5Me5) in solution and at different temperatures. The thermal decomposition of [Cp*Ti(NMe2)Cl-2] at temperatures above 145 degrees C caused the activation of the pentamethylcyclopentadienyl ligand to give the new, geometrically constrained, complex [{eta(5):eta(1)-C5Me4CH2CH2N(Me)}TiCl2] (5). Addition of the isocyanide 2,6-Me2C6H3NC to the solution obtained in this last process led to the isolation of the complex [{eta(5):eta(2)-C5Me4CH2CH2N(Me)CN(C6H3Me2)}TiCl2] (6) by insertion of one isocyanide molecule into the titanium-nitrogen bond in 5. The structure of 6 has been proved by an X-ray diffraction study which showed the organic Ligand, C5Me4CH2CH2N(Me)CN(C6H3Me2), to be coordinated to the titanium atom via the cyclopentadienyl ring and a eta(2)-iminocarbamoyl fragment. Heating of the trinuclear oxo derivative [{Cp*Ti(NMe2)}(3)(mu-O)(3)] at 110 degrees C gave the complex [{Cp*Ti-3(3)(NMe2) (mu-eta(2)-CH2NMe)}(mu-O)(3)] (4) where an imine Ligand bridges two of the three metallic centres.