Exclusively hydrogen-substituted arsanylboranes: The synthesis of the unprecedented Lewis base stabilized monomeric parent compound of the arsanylborane H2AsBH2⋅NMe3 was achieved in a one-pot reaction in high yield and purity. The analogous phosphanylborane was synthesized in a similar manner. A series of different reactions was performed on H2AsBH2⋅NMe3 to show its broad reactivity pattern.

Upon reacting P(4)S(3) with AgAl(hfip)(4) and AgAl(pftb)(4) [hfip = OC(H)(CF(3))(2); pftb = OC(CF(3))(3)], the compounds Ag(P(4)S(3))Al(hfip)(4) 1 and Ag(P(4)S(3))(2)(+)[Al(pftb)(4)](-) 2 formed in CS(2) (1) or CS(2)/CH(2)Cl(2) (2) solution. Compounds 1 and 2 were characterized by single-crystal X-ray structure determinations, Raman and solution NMR spectroscopy, and elemental analyses. One-dimensional chains of [Ag(P(4)S(3))(x)](infinity) (x = 1, 1; x = 2, 2) formed in the solid state with P(4)S(3) ligands that bridge through a 1,3-P,S, a 2,4-P,S, or a 3,4-P,P eta(1) coordination to the silver ions. Compound 2 with the least basic anion contains the first homoleptic metal(P(4)S(3)) complex. Compounds 1 and 2 also include the long sought sulfur coordination of P(4)S(3). Raman spectra of 1 and 2 were assigned on the basis of DFT calculations of related species. The influence of the silver coordination on the geometry of the P(4)S(3) cage is discussed, additionally aided by DFT calculations. Consequences for the frequently observed degradation of the cage are suggested. An experimental silver ion affinity scale based on the solid-state structures of several weak Lewis acid base adducts of type (L)AgAl(hfip)(4) is given. The affinity of the ligand L to the silver ion increases according to P(4) < CH(2)Cl(2) < P(4)S(3) < S(8) < 1,2-C(2)H(4)Cl(2) < toluene.

The reaction of iPr3SiPLi2 with SnCl2 in the mol ratio 1:1 leads to the formation of [Sn7(PSiiPr3)7] (1). The cluster [Sn8(PSiiPr3)6Cl2] (3) is obtained, if the same reaction is carried out with a slight excess of the metal salt. Similar lithium chloride elimination reactions between SnCl2 and iPr3SiAsLi2 in the mol ratio 1:1 and 2:3, however, yield [Sn7(AsSiiPr3)7] (2) and [Sn4(AsSiiPr3)6Li4(Et2O)2] (4), respectively. The metal salt GeCl2(diox)2 (diox = 1,4‐dioxane) reacts with iPr3SiPLi2 to give [Ge6(PSiiPr3)6] (5). Compounds 1−5 were characterised by NMR and IR spectroscopic techniques as well as elemental analysis. The crystal structures were identified by X‐ray diffraction analysis, which confirmed that the heptameric skeletons of 1 and 2 are structurally analogous. The Sn/P cluster 3 contains subvalent tin atoms, while 4 forms a Sn4As6Li4 rhombododecahedron and 5 a slightly distorted hexagonal prism. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

The reactions of 2‐borane‐1,3,4,5‐tetramethylimidazoline (BH3·NHCMe) with selected phosphane adducts of the Lewis acids B(C6F5)3 and Ga(C6F5)3 are studied. Among others, adducts (C6F5)3Ga·PH2Cp* (1a) and (C6F5)3B·PH2Cp* (2) are used as starting materials. When the (C6F5)3Ga–phosphane adducts 1a and (C6F5)3Ga·PPhH2 are treated with BH3·NHCMe, the Lewis acid/base stabilised phosphanylboranes (C6F5)3Ga·P(Cp*)HBH2·NHCMe (3a) and (C6F5)3Ga·P(Ph)HBH2·NHCMe (3b) are formed, respectively, by a hydrogen elimination reaction. In contrast, the reaction of BH3·NHCMe with the (C6F5)3B–phosphane adducts (C6F5)3B·PH2R [R = H, R = Cp* (2) and R = Ph] in CH2Cl2 at room temperature leads to the formation of a salt with the general formula [(C6F5)3BH][RPH2·BH2·NHCMe] (4a: R = H, 4b: R = Cp*, 4c: R = Ph). To synthesise the Lewis acid/base stabilised phosphanylborane with (C6F5)3B as a Lewis acid and 1,3,4,5‐tetramethylimidazolylidene (NHCMe) as a Lewis base, a different synthetic pathway was applied: the replacement reaction of the Lewis base. At room temperature, NHCMe displaced the amine in (C6F5)3B·P(Ph)HBH2·NMe3 to yield (C6F5)3B·P(Ph)HBH2·NHCMe (5). All compounds were comprehensively characterised by spectroscopic methods. Compounds 1a, 1b, 2, 3a, 3b and 5 were additionally characterised by X‐ray crystallographic analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The halogenation of Lewis-acid/base-stabilised phosphanylboranes () and arsanylboranes () with CX4 (X=Cl, Br) leads selectively to the substitution of both protons at the pentel atom and the new compounds [(CO)5W(X2PBH2.NMe3)] (:X=Cl, :X=Br) and [(CO)5W(X2AsBH2.NMe3)] (:X=Cl, :X=Br), respectively, are obtained. The new products were comprehensively characterised by spectroscopic methods and by X-ray crystallography. While compounds and show an antiperiplanar arrangement of the Lewis acid (W(CO)5) and the Lewis base (NMe3) in the solid state, a synclinal arrangement in and , respectively, was observed. Computational calculations of the optimised antiperiplanar and synclinal geometries of the compounds and in the gas phase slightly favour the antiperiplanar arrangement of the Lewis acid and the Lewis base for both compounds.