Trapping Aluminum Hydroxide Clusters with Trisilanols during Speciation in Aluminum(III)-Water Systems: Reproducible, Large Scale Access to Molecular Aluminate Models
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- 作者：Dr. Kapil Shyam Lokare ; Nicolas Frank ; Dr. Beatrice Braun-Cula ; Dr. Itziar Goikoetxea ; Prof. Dr. Joachim Sauer and Prof. Dr. Christian Limberg
- 刊名：Angewandte Chemie
- 出版年：2016
- 出版时间：September 26, 2016
- 年：2016
- 卷：128
- 期：40
- 页码：12513-12517
- 全文大小：1385K
- ISSN：1521-3757
文摘
To gain molecular level insights into the properties of certain functions and units of extended oxides/hydroxides, suitable molecular model compounds are needed. As an attractive route to access such compounds the trapping of early intermediates during the hydrolysis of suitable precursor compounds with the aid of stabilizing ligands is conceivable, which was tested for the aluminum(III)/water system. Indeed, trisilanols proved suitable trapping reagents: their presence during the hydrolysis of AliBu2H in dependence on the amount of water used allowed for the isolation of tri- and octanuclear aluminum hydroxide cluster complexes [Al3(μ2-OH)3(THF)3(PhSi(OSiPh2O)3)2] (1) and [Al8(μ3-OH)2(μ2-OH)10(THF)3(p-anisylSi(OSiPh2O)3)4] (2). 1 can be regarded as the Al(OH)3 cyclic trimer, where six protons have been replaced by silyl residues. While 2 features a unique [Al8(μ3-OH)2(μ2-OH)10]12+ core. In contrast to most other known aggregates of this type, 1 and 2 can be readily prepared at reasonable scales, dissolve in common solvents, and retain an intact framework even in the presence of excessive amounts of water. This finding paves the way to future research addressing the reactivity of the individual functional groups.