The first monomeric crystalline tin(<scp>II</scp>) alkyls; X-ray structures of the β-N-functionalised alkyls Sn(R)X [R= C(SiMe₃)₂C₅H₄N–2 and X= R, Cl, or N(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(OC6H3But2-2,6)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).