Some insertion reactions into the Ti–Me bond of [Ti(η5-C5Me5)MeCl2]; crystal structures of [Ti(η5-C5Me5)(η2-COMe)Cl2] and [{Ti(η5-C5Me5)}2(µ-Cl)2{µ-η4-CH2-(2,6-me2C6H3N)CC(NC6H3Me2-2,6)CH2}]

Abstract

Treatment of [Ti(C₅Me₅)Cl₃] with trimethylaluminium gives [Ti(C₅Me₅)MeCl₂], which reacts readily with CO, CNC₆H₃Me₂-2,6 and N₂CPh₂ to give the corresponding acyl [Ti(C₅Me₅)(η²-COMe)Cl₂], iminoacyl [Ti(C₅Me₅){η²-MeCN(C₆H₃Me₂-2,6)}Cl₂] and hydrazonato [Ti(C₅Me₅){η²-N(Me)NCPh₂}Cl₂] insertion products. The compound [Ti(C₅Me₅)(η²-COMe)Cl₂] reacts with PMe₃ to give [Ti(C₅Me₅){η²-OC(PMe₃)Me}Cl₂] and [Ti(C₅Me₅){OC(CNC₆H₃Me₂-2,6)Me}Cl₂] has been identified by NMR spectroscopy as the product of a similar nucleophilic attack by CNC₆H₃Me₂-2,6. The reaction of [Ti(C₅Me₅){η²-MeCN(C₆H₃Me₂-2,6)}Cl₂] with nucleophilic agents like Li[N(SiMe₃)₂] leads to [{Ti(C₅Me₅)}₂(µ-Cl)₂{µ-η⁴-CH₂(2,6-Me₂C₆H₃N)CC(NC₆H₃Me₂-2,6)CH₂}]. The crystal structures of the latter and of [Ti(C₅Me₅)(η²-COMe)Cl₂] have been established by X-ray diffraction methods; the mononuclear compound shows a pseudo-square-pyramidal geometry with a strong Ti–[η²-C(Me)O] interaction, while the dinuclear compound contains two Ti(C₅Me₅) groups bridged by two chlorine atoms and by the new ligand η⁴-CH₂(2,6-Me₂C₆H₃N)CC(NC₆H₃Me₂-2,6)CH₂ reported here for the first time.