Donor-Functionalized Lanthanide Terphenyl Complexes:  Synthesis and Structural Characterization of 2,6-Di(<i>o</i>-anisol)phenyl Compounds of Ytterbium, Yttrium, and Samarium

Abstract

The syntheses and molecular structures of a number of 2,6-di(o-anisol)phenyl ([double bond]Danip-) -based bis(amide) and bis(alkoxide) compounds of ytterbium, yttrium, and samarium are reported. Additionally, NMR spectroscopic data are reported for the analogous diamagnetic yttrium compounds. Salt metathesis reaction of equimolar amounts of DanipLi and YbCl(3) in tetrahydrofuran at room temperature followed by addition of 2 equiv of KN(SiMe(3))(2) or KN(SiHMe(2))(2) produces DanipYb[N(SiMe(3))(2)](2) (1) and DanipYb[N(SiHMe(2))(2)](2) (2), respectively. The analogous reaction using SmCl(3) and KN(SiHMe(2))(2) produces DanipSm[N(SiHMe(2))(2)](2) (3). Reaction of DanipLi and YbCl(3) in tetrahydrofuran at room temperature followed by addition of 2 equiv of KO(2,6-diisopropylphenyl) produces DanipYb[O(2,6-diisopropylphenyl)](2) (4). Our attempts to also prepare the yttrium analogue of complex 4 yielded single-crystalline material of the tetrahydrofuran adduct DanipY(THF)[O(2,6-diisopropylphenyl)](2) (5). The molecular structures of the complexes 1-4 feature five-coordinate metal atoms and coordination polyhedra which can be described as distorted square-pyramidal rather than trigonal-bipyramidal, with the ipso carbon atom occupying the apical position. On the other hand, the molecular structure of the tetrahydrofuran-solvated yttrium Danip arylalkoxide compound 5 features a six-coordinate metal atom in a distorted trigonal-prismatic coordination environment. In all cases the Danip ligand system adopts the chiral (racemic) d,l form.