Adducts of Lewis acidic stibanes with phosphane chalcogenides.

Starting from ClSbR (R = CF, 3,5-(CF)CH) and H(E)P(Bu) (E = O, S), we prepared the oxy- and sulphanediyl-bridged adducts RSb(Cl)-E-(H)P(Bu), which are stable against the elimination of HCl. The different electron-withdrawing substituents and chalcogen bridging units influence the size of the Sb-E-P angle. ClSb(CF) and BuSnH react to give HSb(CF), which seems to interact weakly with H(O)P(Bu) in solution as observed NMR.

A geminal antimony(iii)/phosphorus(iii) frustrated Lewis pair.

The geminal Lewis pair (FC)SbCHP(Bu) (1) was prepared by reacting (FC)SbCl with LiCHP(Bu). Despite its extremely electronegative pentafluoroethyl substituents, the neutral 1 exhibits a relatively soft acidic antimony function according to the HSAB concept (hard-soft acid-base). These properties lead to a reversibility in the binding of CS to 1, as observed by VT-NMR spectroscopy, while no reaction with CO is observed.

Oxidation-dependent Lewis acidity in chalcogen adducts of Sb/P frustrated Lewis pairs.

The reactions of the frustrated Lewis pair (FC)SbCHP(Bu) with oxygen, sulphur, selenium and tellurium led to the mono-oxidation products (FC)SbCHP(E)(Bu) (E = O, S, Se, Te). Further oxidation of these chalcogen adducts with tetrachloro--benzoquinone (-chloranil) gave (FC)Sb(CH)(μ-E)P(Bu)·Cat (Cat = -OCCl) with a central four-membered ring heterocycle for E = O, S, and Se. For E = Te the elimination of elemental tellurium led to an oxidation product with two equivalents of -chloranil, (FC)SbCHP(Bu)·2Cat, which is also accessible by reaction of (FC)SbCHP(Bu) with -chloranil.

Poly-pnictogen bonding: trapping halide ions by a tetradentate antimony(iii) Lewis acid.

A highly halide affine, tetradentate pnictogen-bonding host-system based on the -photodimer of 1,8-diethynylanthracene was synthesized by a selective tin-antimony exchange reaction. The host carries four C[triple bond, length as m-dash]C-Sb(CF) units and has been investigated regarding its ability to act as a Lewis acidic host component for the cooperative trapping of halide ions (F, Cl, Br, I). The chelating effect makes this host-system superior to its bidentate derivative in competition experiments.

A Bidentate Antimony Pnictogen Bonding Host System.

A bidentate pnictogen bonding host-system based on 1,8-diethynylanthracene was synthesized by a selective tin-antimony exchange reaction and investigated regarding its ability to act as a Lewis acidic host component for the complexation of Lewis basic or anionic guests. In this work, the novel C≡C-Sb(C F ) unit was established to study the potential of antimony(III) sites as representatives for the scarcely explored pnictogen bonding donors. The capability of this partly fluorinated host system was investigated towards halide anions (Cl , Br , I ), dimethyl chalcogenides Me Y (Y=O, S, Se, Te), and nitrogen heterocycles (pyridine, pyrimidine).