Lanthanoid Biphenolates as a Rich Source of Lanthanoid-Main Group Heterobimetallic Complexes.

Several new trivalent dinuclear rare earth 2,2'-methylenebis(6-tert-butyl-4-methylphenolate) (mbmp 2- ) complexes with the general form [Ln 2 (mbmp) 3 (thf) n ] (Ln=Sm 1, Tb 2 (n=3), and Ho 3, Yb 4 (n=2), and a tetravalent cerium complex [Ce(mbmp) 2 (thf) 2 ] (5) have been synthesised by RTP (redox transmetallation/protolysis) reactions from lanthanoid metals, Hg(C 6 F 5 ) 2 and the biphenol mbmpH 2 . These new complexes and some previously reported partially protonated rare earth biphenolate complexes [Ln(mbmp)(mbmpH)(thf) n ] react with lithium, aluminium, potassium and zinc organometallic reagents to form lanthanoid-main group heterobimetallic species. When reaction mixtures containing the Ln biphenolate complexes were treated with n-butyllithium, both molecular ([Li(thf) 2 Ln(mbmp) 2 (thf) n ] (Ln=La 6, Pr 7 (n=2) and Er 8, Yb 9, and Lu 10 (n=1)) and charge separated ([Li(thf) 4 ][Ln(mbmp) 2 (thf) 2 ] (Ln=Y 11, Sm 12, Dy 13, and Ho 14) complexes were isolated. Treatment with trimethylaluminium also led to isolation of molecular ([AlMe 2 Ln(mbmp) 2 (thf) 2 ] (Ln=Pr 15, Sm 16, and Tb 17)) and ionic [La(mbmp)(thf) 5 ][AlMe 2 (mbmp)] (18) complexes. One gadolinium-potassium ([K(thf) 3 Gd(mbmp) 2 (thf) 2 ] (19)), and one ytterbium-zinc species ([ZnEtYb(mbmp) 2 (thf)] (20)) were isolated from treatment of reaction mixtures with potassium bis(trimethylsilyl)amide and diethylzinc respectively.