Steric saturation of the ytterbium coordination environment:: (TptBu, Me)Yb(OMes), a four coordinate, monomeric, base-free divalent lanthanide complex, its solvation with tetrahydrofuran, and comparison to the β-diketonate complex, (TptBu, Me)Yb(dpm)

Reaction of (Tp(tBu,Me))Yb(I)(THF) with KOMes (Mes = 2,4,6-C6H2Me3) in tetrahydrofuran (THF) at -45 degreesC afforded the monomeric divalent lanthanide aryloxide complex (Tp(tBu,Me))Yb(OMes)(THF) (1). Reaction of [(Tp(tBu,Me))Yb(mu-H)](2) (Tp(tBu,Me) = hydrotris(3-tert-butyl-5-methylpyrazolyl)borate) with HOMes in benzene at ambient temperature gave the monomeric solvent free lanthanide aryloxide complex (Tp(tBu,Me))Yb(OMes) (2). Dissolution of 2 in tetrahydrofuran at ambient temperature resulted in clean transformation to the solvated complex 1. The coordinated THF ligand is persistent in non-ethereal solvents. Reaction of [(Tp(tBu,me))Yb(mu-H)]2 with dipivaloylmethane (Hdpm) afforded the related beta-diketonate complex (Tp(tBu,me))Yb(dpm) (3). Complexes 1-3 have been fully characterized by spectroscopic methods and their structures were confirmed by X-ray crystallographic studies. Crystal data: C38.5H62.5BN6O2Yb (1(.)0.25 C6H14): monoclinic, C2/c, a = 21.526(4) Angstrom, b = 13.213(2) Angstrom, c = 31.403(7) Angstrom, beta = 105.80(2)degrees, Z = 8; C33H51BN6OYb (2): orthorhombic, Pbcm, a = 10.5344(5) Angstrom, b = .20.3495(7) Angstrom, c = 16.3768(6) Angstrom, Z = 4; C35H59BN6O2Yb (3): monoclinic, C2/c, a = 13.370(1) Angstrom, b = 21.134(2) Angstrom, c = 28.242(2) Angstrom, beta = 97.356(2)degrees, Z = 8. (C) 2003 Elsevier Ltd. All rights reserved.