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' s alts [(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 alkal i metal reagents LiOAr, KOAr, and NaC5Me5 (DME = dimethoxyethane). The yttrium center in complex 2 is square pyramidal with the terminal ary loxide ligand in the apical position and no agostic interactions. The octahedral coordination environment around yttrium in 3 is formed by t wo 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) A ngstrom. Complex 4 contains an isolated hexasolvated cation and a form ally 6-coordinate yttrium atom in which the three aryloxide oxygen ato ms and the eta(5)-C5Me5 ring centroid describe a distorted tetrahedron . (C) 1998 Elsevier Science S.A.