Guanidinate borohydride derivatives of lanthanides: synthesis and molecular structures of the [(Me3Si)2NC(NCy)2]Gd(BH4)2DME and [{(Me3Si)2NC(NPr~i)2}2Sm(BH4)2]~-[Li(DME)3]~+ complexes. Catalytic activity of the [(Me3Si)2NC(NCy)2]2Ln(BH4)2Li(THF)2 complexes (Ln = Nd, Sm, or Yb) in methyl methacrylate polymerization

摘要

The reaction of Gd(BH4)3(THF)2 with two equivalents of sodium N,N'-dicyclohexyl-N"-bis(trimethylsilyl)guanidinate in THF followed by the treatment of the reaction product with 1,2-dimethoxyethane produced the monoguanidinate bis(borohydride) complex [(Me3Si)2NC(NCy)2]Gd(BH4)2DME (1) (Cy is cyclohexyl). The treatment of the hetero-bimetallic samarium complex {(Me3Si)2NC(NPr~i)2}2Sm(BH4)2Li(THF)2, in which the lan-thanide and lithium atoms are linked by two bridging borohydride groups, with 1,2-dimethoxy-ethane afforded the ionic complex [{(Me3Si)2NC(NPr~i)2}2Sm(BH4)2]~-[Li(DME)3]~+ (2). The structures of complexes 1 and 2 were established by X-ray diffraction. The [(Me3Si)2NC(NCy)2]2Ln(BH4)2Li(THF)2 complexes (Ln = Nd (3), Sm (4), or Yb (5)) were found to catalyze methyl methacrylate polymerization.