The first monomeric crystalline tin(II) alkyls; X-ray structures of the β-N-functionalised alkyls Sn(R)X [= (SiMe3)2C5H4N–2 and = , C, or (SiMe3)2]

Abstract

Monomeric 2-pyridylbis(trimethylsilyl)methyltin(II) compounds Sn(R)X [= (SiMe₃)₂C₅H₄N-2 and = (1), l (2), or (SiMe₃)₂(3)] were prepared from (LiR)₂ and (a) SnCl₂ or Sn(OC₆H₃Bu^t₂-2,6)₂(1), (b) 2SnCl₂(2), or (c) Sn[N(SiMe₃)₂]₂(3); their X-ray structures show that the ligands are invariably bonded to tin in a chelating fashion in the crystal with Sn–C and Sn–NC₅H₄ bond lengths of 2.35(2) and 2.42(2)(1), 2.32(2) and 2.27(3)(2), and 2.356(8) and 2.299(5)Å(3), respectively, but in C₆D₅CD₃ solution there appear to be (n.m.r.) C₅H₄N–Sn dissociative processes (ΔG^‡ca. 43 ± 2 kJ mol^–1).