Samarium alkyl-aryloxide complex containing a trigonal bipyramidal carbon atom. X-ray structure of [Li(THF)][sub 2][Sm(O-2,6-i-Pr[sub 2]C[sub 6]H[sub 3])[sub 3] CH[sub 2]SiMe[sub 3][sub 2]]

Reaction of Sm(O-2,6-i-Pr[sub 2]C[sub 6]H[sub 3])[sub 3](THF)[sub 2] (1) with 3 equiv of LiCH[sub 2]SiMe[sub 3] in THF solution produces the salt complex (Me[sub 3]SiCH[sub 2])Sm[([mu]-OAr)([mu]-CH[sub 2]SiMe[sub 3])Li (THF)][([mu] -OAr)[sub 2]Li(THF)] (2, Ar = 2,6-i-Pr[sub 2]C[sub 6]H[sub 3]) in 58% yield. [sup 1]H and [sup 13]C NMR are extremely complex, while [sup 7]Li NMR is indicative of an equilibrium between 2 and free LiO-2,6-i-Pr[sub 2]C[sub 6]H[sub 3] in solution. Compound 2 contains a pentacoordinate samarium metal center ligated by one terminal and one bridging CH[sub 2]SiMe[sub 3] ligand and three bridging O-2,6-i-Pr[sub 2]C[sub 6]H[sub 3] ligands. Each lithium atom is coordinated to one molecule of THF and either two aryloxide ligands or one aryloxide and one alkyl bridging ligand. 39 refs., 1 fig., 3 tabs.