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Germanium cubed: Addition of [Ge{N(SiMe3)2}2] to a suspension of RSi(OH)3 (R=(2,6‐iPr2C6H3)N(SiMe3)) in hexane/THF affords the germanium siloxane 1 with terminal GeH units in good yield. Compound 1 contains a Ge4O12Si4 cubic polyhedron core in which the corners of the cube are alternately occupied by germanium and silicon atoms. Each of the twelve edges of the cube contains one bridging oxygen atom.

Reaction of LAl (1) or [LAl{η2‐C2(SiMe3)2}] (2) {L = HC[(CMe)(NAr)]2, Ar = 2,6‐iPr2C6H3} with azobenzene affords a five‐membered ring compound [LAl{N(H)‐o‐C6H4N(Ph)}] (3). In the formation of 3 a three‐membered intermediate [LAl(η2‐N2Ph2)] (A) is suggested by a [1 + 2] cycloaddition reaction; A is not stable and further rearranges to 3. DFT calculations on similar compounds with modified L' {L' = HC[(CMe)(NPh)]2} show that the complexation energy of the reaction of L'Al with azobenzene to form [L'Al(η2‐N2Ph2)] is about–39 kcal mol–1, and the best estimate of the energy difference between [L'Al(η2‐N2Ph2)] and [L'Al{N(H)‐o‐C6H4N(Ph)}] is–76 kcal mol–1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

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In continuation of our previous work on the synthesis of zinc siloxanes to understand the influence of stoichiometry in the assembly of polyhedral zinc siloxanes, we have carried out two different reactions between RSi(OH)3 [R = (2,6-i-Pr2C6H3)N(SiMe3)] and ZnMe2 in molar ratios of 1:3 and 1:1.75. In these reactions, we have isolated an octanuclear Zn8Me7(dioxane)2(O3SiR)3 (5) and a heptanuclear zinc siloxane [Zn7Me2(THF)5(O3SiR)4] (6), respectively. Compound 5 is a complex cage structure and can be understood as being a derivative of a drum-shaped species containing a Zn7Si3O9 core. In contrast, 6 consists of a Zn4Si4O12 unit with zinc and silicon atoms occupying alternate corners of the cube; three contiguous faces of this cube are capped by zinc atoms, leaving the other three faces open.

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Ein Ge‐Si‐Würfel: Bei der Zugabe von [Ge{N(SiMe3)2}2] zu einer Suspension von RSi(OH)3 (R=(2,6‐iPr2C6H3)N(SiMe3)) in Hexan/THF entsteht in guter Ausbeute das Germaniumsiloxan 1 mit endständigen Ge‐H‐Einheiten. Verbindung 1 enthält einen kubischen Ge4O12Si4‐Polyederkern mit abwechselnd Germanium‐ und Siliciumatomen an den Ecken. Alle zwölf Würfelkanten sind durch Sauerstoffatome überbrückt.