Synthesis and structural characterisation of the first neutral homoleptic lanthanide metal(III) alkyls: [LnR3][Ln = La or Sm, R = CH(SiMe3)2]

Abstract

The alkylating agent LiR [R = CH(SiMe₃)₂] reacts with [Ln(OC₆H₃Bu^t₂-2,6)₃](Ln = La or Sm) under ambient conditions to yield [LnR₃][Ln = La (1) or Sm (2)], the first structurally characterised neutral homoleptic alkyls of the lanthanide metals; the crystalline compounds (1) and (2) have C₃ symmetry and almost tetrahedral CLnC′ angles, with Ln–C bonds of 2.515(9)(1) or 2.33(2)Å(2), and unusually short Ln ⋯ CH₃ contacts [3.121(9)(1) or 2.85(3)Å(2)].