Yttrium alkyl complex with a linked bis(amidinate) ancillary ligand

The dilithium salt of a linked bis(amidinate) dianionic ligand, Li2[Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3] (1), was prepared by reaction of dilithiated N,N'-bis(trimethylsilyl)-1,3-diaminopropane with benzonitrile. Reaction of 1 with YCl3(THF)3.5 gave [Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3]YCl(THF)2 (2), which, by reaction with Li[CH(SiMe3)2], was converted to the alkyl complex [Me3SiNC(Ph)N(CH2)3NC(Ph)NSiMe3]Y[CH(SiMe3)2](THF) (3). A structure determination of 3 showed that linking together the amidinate functionalities opens up the coordination sphere to allow the bonding of an additional molecule of THF not present in the unbridged bis(amidinate) analogue [PhC(NSiMe3)2]2Y[CH(SiMe3)2].