Ueber gemischte Gruppe 14-Gruppe 14-Bindungen. V. Sechs Perphenylierte Propan-Analoga Ph3M-M'Ph2-M''Ph3 (M, M', M'' = Si/Ge): ein Beitrag zum Elektronegativitaetsunterschied zwischen Silicium und Germanium

Article abstract of DOI:10.1016/0022-328X(93)80184-D

The six title compounds have been synthesized from Li/K-Si/GePh3 and chloride precursors in THF, DMF or diethyl ether at low temperature.The six compounds crystallize isomorphously in the space group Pbca with ordered arrangement for the four symmetrical cases (Si-Si 2.394, Si-Ge 2.412, Ge-Ge 2.440 Angstroem) and statistical alignment for the two asymmetrical chains; angle range 116.6-123.3 deg.Replacement of Si by Ge atoms leads to low field NMR chemical shifts for 13C_ipso atoms and for directly bonded 29Si atoms.This is in accordance with an enhanced electronegativity of germanium in comparison with silicon.UV/Vis and IR/Raman data are given.