Distinct Reactivity of Trimethylytterbium toward AlMe 3 and GaMe 3 : Synthesis of Donor-Stabilized Dimethylytterbium.

Me 3 TACN (1,4,7-trimethyl-1,4,7-triazacyclononane)-stabilized trimethylytterbium was obtained via a salt-metathesis protocol employing [(Me 3 TACN)YbCl 3 ] and methyllithium. Complex [(Me 3 TACN)YbMe 3 ] seems not to engage in redox chemistry with potassium graphite and is thermally quite stable in the solid state. Treatment of trivalent [(Me 3 TACN)YbMe 3 ] with 3 equiv. of AlMe 3 afforded divalent tetramethylaluminate complex [(Me 3 TACN)Yb(AlMe 4 ) 2 ]. The reaction of [(Me 3 TACN)YbMe 3 ] with GaMe 3 in THF gave trivalent ion pair [(Me 3 TACN)YbMe 2 (thf)][GaMe 4 ], which is susceptible to reduction with KC 8 . The thermally very labile divalent [(Me 3 TACN)YbMe(μ-Me)] 2 is the first discrete donor adduct of a divalent dimethyl rare-earth-metal complex.