Synthese und Struktur von Galliumsiloxankäfigen: Modellsubstanzen für galliumhaltige Silicate

Abstract

Molekularsiebe aus dem Baukasten?! Die Galliumsiloxane nebenstehend gezeigten Typs (Substituenten an Si‐ und Ga‐Atomen sind weggelassen), die jetzt erstmals synthetisiert und strukturell charakterisiert wurden, erhöhen die Zahl der Moleküle, die potentiell für die gezielte Synthese von zeolithartigen Verbindungen in Frage kommt. Auch das Verständnis von Katalyseprozessen könnte durch das Studium solcher Modellverbindungen verbessert werden.

Organosilanetriols: model compounds and potential precursors for metal-containing silicate assemblies

“…The anionic cubic gallium-and indium-containing siloxanes have been prepared starting from LiMMe 4 (M = Ga or In). 54,55 Thus, when the reactions of 4 and 6 are carried out with LiMMe 4 in refluxing hexane-THF in a 1:1 reactant ratio, the anionic cages 40-43 are obtained (Scheme 13). The molecular structures of the gallium and indium siloxanes 41 and 43 have been determined by X-ray diffraction studies.…”

“…The reaction of silanetriols 4 and 6 with GaMe 3 or InMe 3 in refluxing hexane/1,4-dioxane leads to the products 32-35, respectively (Scheme 11). 54,55 In the resulting products, the Ga and In centers are coordinated to a dioxane solvent molecule.…”

POLYCYCLES AND CAGES IN MOLECULAR ALUMO-POLYSILOXANES—(Ph2SiO)8[Al(O)OH]4 Used as a Supramolecular Target and “Auto-Condensation” Within the Molecule

“…Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions with a very rich synthetic and structural chemistry. It is astonishing to find that systematic replacements of R 2 SiO or RSiO 1.5 groups within these chain-, ring-, and cage-like compounds by XAlO 1−7 or XGaO 8,9 entities (X = monovalent ligand) not attracted too much attention until now; although in solid state materials like silicates such replacements of silicon by aluminum they are well known and have important implications (see zeolites for example.) 10 …”

Control of Molecular Topology and Metal Nuclearity in Multimetallic Assemblies: Designer Metallosiloxanes Derived from Silanetriols

“…Polyhedral neutral aluminosiloxanes were isolated with an Si/Al ratio of 1:1 13. 14 By adopting a similar procedure and by using GaMe 3 and InMe 3 , the corresponding neutral gallio 3 and indiosiloxanes 4 could also be prepared (Scheme ) 15. 16 It is quite important to mention here that in spite of the multifunctional nature of the reactants, a single product in high yields is isolated in these reactions in a manner that is reminiscent of self‐assembly reactions.…”

“…This illustrates the applicability of utilizing soluble polyhedral metallosiloxanes to model natural and synthetic minerals. By using a similar synthetic procedure, the reaction of RSi(OH) 3 and LiMMe 4 (M=Ga, In) afforded the ionic gallio and indio siloxanes Li 4 [{Ga(RSiO 3 )(Me)} 4 ] ( 7 )15 and Li 4 [{In(RSiO 3 )(Me)} 4 ] ( 8 ),16 respectively. A slight variation was observed in the reaction between RSi(OH) 3 and Na[InMe 4 ].…”