Synthesis and structure of alkali metal 'ate' complexes in the yttrium/2,6-dimethylphenoxide system

The neutral complex Y(OAr)(3)(THF)(3), 1, (Ar = C6H3Me2-2,6) prepared from Y[N(SiMe3)(2)](3) and HOAr, can be converted to the ionic 'ate' salts [(DME)Li](2)[(mu-OAr)(4)Y(OAr)], 2, [(THF)(3)K][(mu-OAr)(2)Y(OAr)(2)(THF)(2)], 3, and [Na(THF)(6)][(C5Me5)Y(OAr)(3)], 4, with the alkali metal reagents LiOAr, KOAr, and NaC5Me5 (DME = dimethoxyethane). The yttrium center in complex 2 is square pyramidal with the terminal aryloxide ligand in the apical position and no agostic interactions. The octahedral coordination environment around yttrium in 3 is formed by two bridging aryloxides, two terminal aryloxides and two THF molecules. This complex has close K-C(ipso) contacts of 3.288(9) and 3.400(10) Angstrom. Complex 4 contains an isolated hexasolvated cation and a formally 6-coordinate yttrium atom in which the three aryloxide oxygen atoms and the eta(5)-C5Me5 ring centroid describe a distorted tetrahedron. (C) 1998 Elsevier Science S.A.