Silyl‐ and Germyl‐Substituted Diorganophosphonites

The syntheses of triorganosilyl- and triorganostannyl-substituted diorganophosphonites as well as an evaluation of their Lewis basicity are reported. Reactions of triphenylsilyl-dialkylphosphonites with selenium proceed via initial formation of spectroscopically observable P-oxidation products that are unprecedented for phosphine derivatives with P−Si bonds.

Abstract

Reactions of metalated diorganophosphonite boranes with triorganosilyl and -germyl halides provided borane adducts of diorgano(tetryl)phosphonites. Further treatment with excess Et₃N or DABCO yielded the borane-free species (RO)₂P-ER′₃ (E=Si, Ge; R, R′=alkyl, aryl). The products of all reactions were characterized by elemental analyses and NMR data, and in selected cases by MS and single-crystal XRD studies. Reactions of selected ligands with Ni(CO)₄ and selenium were shown to produce Ni(CO)₃-complexes or diorgano(tetryl) phosphonoselenoates (RO)₂(R′₃E)P=Se, respectively, which were identified spectroscopically but could not be isolated. Evaluation of the TEP and ¹ J _PSe coupling constants were used for a first assessment of the electron donor properties of the new molecules.

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