Ytterbium aryloxides

Figure 6.13 Crystal structure of Yb6( X3-OH)4( x,r -OC6H4OMe)i0(r -OC6H4OMe)2(OC6H4OMe)2 [33]. (Redrawn from J. Carretas et al., Synthesis and characterization of samarium, europium and ytterbium aryloxides. Crystal structure of [Yb6(0H)4(0C6H40Me)i4]-4THF, Journal of Alloys and Compounds, 376, 289-292, 2006.)...

The different products which are obtained due to hydroxybenzyl migration can be trapped by metal complexation. The thus formed trivalent, N403-encapsulating ligand adopts a pentagonal bipyramidal geometry at the ytterbium center with two aryloxide oxygens in the axial positions. 

The reaction product of ytterbium metal with benzophenone in a 1 1 molar ratio could be determined by an X-ray structure [278]. The benzophenone dianion unsymmetrically bridges the ytterbium atoms in the HMPA solvate [Yb(OCPh2)2(HMPA)2]2. The aryl oxygen forms a Yb-O bond with a typical terminal bond length (Table 18), but also donates to the other ytterbium. A Yb-C a-bond involving the a-C-atom (2.59(5) A) balances the charge at Yb (II). Reaction of the dianionic complex with four equivalents of phenol HOC6H3tBu2-2,6-Me-4 afforded the mononuclear aryloxide complex Yb(OAr)2(HMPA)2 (Sect. 4.2) [72],... 

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