Molecular Structures of the Pyridine-2-olates PhE(pyO)3 (E = Si, Ge, Sn)—[4+3]-Coordination at Si, Ge vs. Heptacoordination at Sn

The phenyltetrel pyridine-2-olates PhE(pyO)3 (E = Si, Ge, Sn; pyO pyridine-2-olate) were synthesized from the respective chlorides PhECl3 and 2-hydroxypyridine (2-pyridone) with aid of a sacrificial base (triethylamine). Their solid-state structures determined by single-crystal X-ray diffraction. PhSi(pyO)3 exhibits three-fold capped tetrahedral Si coordination sphere ([4+3]-coordination, Si···N separations ca. 3.0 Å), in accordance previously reported silicon pyridine-2-olates. PhGe(pyO)3 adopts related [4+3]-coordination mode, which differs terms faces pyridine N atoms. Additionally, shorter Ge···N (2.8–2.9 Å) indicate trend toward tetrel hypercoordination. PhSn(pyO)3 features heptacoordinate tin within pentagonal bipyramidal Sn (Sn···N 2.2–2.4 Å). For compounds, 29Si 119Sn NMR spectroscopy indicates retention their number chloroform solution.