Rare-earth-metal trimethylsilylmethyl ate complexes.

En route to putative rare-earth-metal alkylidene complex Li[Lu(CH 2 SiMe 3 ) 2 (CHSiMe 3 )], according to Schumann's original protocol, the reaction of YCl 3 with LiCH 2 SiMe 3 in a mixture of diethyl ether and n -pentane afforded a neosilyl ate complex of composition Li 3 Y(CH 2 SiMe 3 ) 6 . Tetrametallic complex Li 3 Y(CH 2 SiMe 3 ) 6 shows an unprecedented structural motif in the solid state and was further characterized by heteronuclear 1 H/ 13 C/ 7 Li/ 29 Si/ 89 Y, as well as VT NMR and DRIFT spectroscopies. Analysis of the thermolysis product via heteronuclear NMR spectroscopy and its reactivity towards benzophenone gave strong evidence for an alkylidene formation upon decomposition. Application of a similar protocol for the smallest rare-earth-metal scandium led to the isolation of ate complex [Li(thf) 4 ][LiSc 2 (CH 2 SiMe 3 ) 8 ] as the preferred crystallized product. Here, the reaction of adduct ScCl 3 (thf) 3 and LiCH 2 SiMe 3 was performed in Et 2 O/ n -hexane, in the absence of additional THF. The reaction of LaCl 3 (thf) with 3 equiv. of LiCH 2 SiMe 3 in THF/Et 2 O at -40 °C yielded the ate complex [Li(thf) 4 ][La(CH 2 SiMe 3 ) 4 (thf)], which is the first of its kind.