Ytterbium complexes aryls

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],... 

Organolanthanide-catalyzed intermolecular hydrophosphination is a more facile process than intermolecular hydroamination. The reaction of alkynes, dienes, and activated alkenes with diphenylphosphine was achieved utilizing the ytterbium imine complex 9 (Fig. 8) as catalyst [185-188]. Unsymmetric internal alkynes react regioselectively, presumably due to an aryl-directing effect (48) [186]. 

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