6533b834fe1ef96bd129df78
RESEARCH PRODUCT
Tetraaryl-methane analogues in group 14—V. Distortion of tetrahedral geometryin terms of through-space π–π and π–σ interactions andNMR sagging in terms of π–σcharge transfer
Andrea ZickgrafElmar BräuHeike StengerMartin DrägerMichael CharisséDainis DakternieksSilke GerstmannJames M. HookCristelle Desmarquetsubject
SiliconChemical shiftchemistry.chemical_elementTorsion (mechanics)Tetrahedral molecular geometryGermaniumCrystal structureInorganic ChemistryCrystallographychemistryMaterials ChemistryTetrahedronPhysical and Theoretical ChemistryTindescription
Abstract 44 members of thecompound series Ph4−nMRn (M=Si, Ge, Sn, Pb; R=o-, m-, p-Tol; n=0–4) were synthesized (15 newcompounds). The crystal structures of Ph3Sn (o-Tol) and PhSn (o-Tol)3 were determined and compared to 16 known structures. Subject to the distanced (M–C), an interplay between through-space π–π repulsion and π–σ attraction leads to either elongated or compressed tetrahedral geometry. 29 Si-, 119 Sn- and 207 Pb-NMR chemical shifts were determined in solution and in the solid state.73 Ge chemical shifts were measured only in solution. Anupfield or downfield sagging of the chemical shifts along each series is rationalized in terms of a π–σcharge transfer which is constrained by torsion of the aromatic groups.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1998-11-01 | Polyhedron |