1,3-Diphospha-2-silaallylic Lithium Complexes and Anions: Synthesis, Crystal Structures, Reactivity, and Bonding Properties
journal contributionposted on 1998-05-13, 00:00 authored by Dirk Lange, Elke Klein, Holger Bender, Edgar Niecke, Martin Nieger, Rudolf Pietschnig, Wolfgang W. Schoeller, Henri Ranaivonjatovo
Trichlorosilanes RSiCl3 (R = t-Bu, Mes, Cp*, Is, OAr) reacted with a 4-fold excess of lithium phosphanide ArPHLi (Ar = 2,4,6-tBu3C6H2) to form 1,3-diphospha-2-silaallylic complexes 3a−f. From the latter, the corresponding free allylic anions could be liberated by complexation of the lithium cation with -crown-, as could be established on the basis of NMR spectra and X-ray structures. In addition, the bonding in the Li complexes was further investigated using ab initio calculations of double-ξ quality. The influence of cation solvation on the complex geometry was explored as well. The chemical reactivity of 1,3-diphospha-2-silaallylic anions with electrophiles (E = H+, ClPR‘R‘‘) was investigated. 1,3-Diphospha-2-silapropenes 4a−d and 1,3,4-triphospha-2-silabutenes-(1) 5a−e and 6a were prepared.
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Bonding Properties Trichlorosilanes RSiCl 3cation solvationBuOArSynthesichemical reactivityAnionlithium phosphanide ArPHLiLi complexesMecomplexationComplexeDiphosphaallylic anionsReactivityCrystal StructuresdiphosphabasisClPRab initio calculationsNMR spectraCpinfluencetriphosphaLithiumlithium cationlatterelectrophile