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(C6F5)(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)][AlMe2(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.

Automated summary

Several new trivalent dinuclear rare earth complexes were synthesized using RTP reactions. These complexes react with lithium, aluminium, potassium, and zinc organometallic reagents to form lanthanoid-main group heterobimetallic species.