A dimeric aluminium hydroxide supported by a new disiloxide ligand

Weichert, Katja; Carlson, Bryan; Reinke, Helmut; Krempner, Clemens

doi:10.1039/c0dt00507j

Cited by 17 publications

(15 citation statements)

References 21 publications

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“…Complex 1 can be regarded as the Al(OH) 3 cyclic trimer, where six protons have been replaced by silyl residues provided by two clamping tripodal ligands. Well‐characterized compounds containing aluminum hydroxide moieties supported by siloxide ligands are rare ,,. Similarly, molecular aluminum hydroxides with tetra‐coordinated aluminum atoms in general are scarce, as due to their Lewis and Brønsted acidity Al‐OH units tend to aggregate, forming AlO 6 octahedra.…”

Section: Methodsmentioning

confidence: 99%

Trapping Aluminum Hydroxide Clusters with Trisilanols during Speciation in Aluminum(III)–Water Systems: Reproducible, Large Scale Access to Molecular Aluminate Models

et al. 2016

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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(2). 1 can be regarded as the Al(OH)3 cyclic trimer, where six protons have been replaced by silyl residues.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.

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Section: Methodsmentioning

confidence: 99%

Trapping Aluminum Hydroxide Clusters with Trisilanols during Speciation in Aluminum(III)–Water Systems: Reproducible, Large Scale Access to Molecular Aluminate Models

et al. 2016

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“…It is notable that despite the simplicity of splitting polysiloxane using organometallic derivatives, this method is not used widely to prepare PHMSs because the results are often difficult to predict. Branched silane oligomers with rather rigid disilane Si-Si units instead of flexible disiloxane SiOSi fragments have been used to synthesize PHMSs containing Al [126], Ca [127], Ti (86), and Zr (87) [128] (Scheme 30). These types of compounds are considered to be active catalytic systems [129].…”

Section: [119]mentioning

confidence: 99%

Modern concepts and methods in the chemistry of polyhedral metallasiloxanes

Levitsky

Bilyachenko

2016

Coordination Chemistry Reviews

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“…[21] One of these complexes, a monomeric aluminum isopropoxide (Scheme 1) proved to be one of the most active MPV…”

Section: Brianmentioning

confidence: 99%

Synthesis and structure of sterically overloaded tetra-coordinated yttrium and lanthanum disiloxides

McNerney

Mummadi

Hung‐Low

et al. 2016

Inorganic Chemistry Communications

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Synthesis and structure of sterically overloaded tetra-coordinated yttrium and lanthanum disiloxides, Inorganic Chemistry Communications (2016Communications ( ), doi: 10.1016Communications ( /j.inoche.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Synthesis and Structure of Sterically Overloaded Tetra-coordinated Yttrium and Lanthanum DisiloxidesBrian McNerney [a] , Suresh Mummadi [a] , Fernando Hung-Low [a] , David B. Cordes [b] , Daniel K.Unruh [a] , Clemens Krempner* [a] [a] Department of Chemistry & Biochemistry, Texas Tech University, Box 1061, Lubbock, Texas, 79409-1061 In the past half century, rare earth metal siloxides [1] have gained some popularity primarily due to their potential as homogeneous catalysts in polymerization catalysis [2][3][4] , as precursors for the formation of metal oxides and silicates [5][6][7] , and as models for silica-supported lanthanide metal heterogeneous catalysts. [8][9][10][11][12][13] In particular work by the Edelmann group has resulted in significant advancements in the synthesis of rare earth metal complexes supported by the. [12][13][14][15][16][17][18][19][20] Our group recently synthesized a sterically overloaded silanediol of formula (CH 2 SiR 2 OH) 2 (1),where R = Si(SiMe 3 ) 2 Me, and demonstrated that its deprotonated form serves as a dianionic chelating spectator ligand for aluminum alkyls, hydroxides and alkoxides. [21] One of these complexes, a monomeric aluminum isopropoxide (Scheme 1) proved to be one of the most active MPV A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTcatalyst for the reduction of ketones and aldehydes reported so far. [22] Key to its high activty was its monomeric nature enforced by the bulkiness of the supporting disiloxide ligand. Based on these results, we reasoned that sterically overloaded disilanol 1 might be the ideal ligand for the synthesis of heteroleptic and salt-and adduct-free rare earth siloxide complexes, the latter potentially useful as Lewis acid catalysts.Scheme 1. Synthesis of sterically overloaded aluminum disiloxides.We first attempted to prepare the heteroleptic yttrium and lanthanum disiloxides of formula [(CH 2 R 2 SiO) 2 MN(SiMe 3 ) 2 ] (M = Ln, Y; R = SiMe(SiMe 3 ) 2 ) (2), respectively, as illustrated in Scheme 2. Initially, one equivalent of disilanol 1 was reacted with one equivalent of La(N(SiMe 3 ) 2 ) 3 in toluene as solvent. The reaction, however, did not give 2 but instead yielded the spirocyclic lanthanum disiloxide 3 as the main product irrespective whether toluene, THF or hexanes were used as solvents. Best yield...

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A dimeric aluminium hydroxide supported by a new disiloxide ligand

Cited by 17 publications

References 21 publications

Trapping Aluminum Hydroxide Clusters with Trisilanols during Speciation in Aluminum(III)–Water Systems: Reproducible, Large Scale Access to Molecular Aluminate Models

Trapping Aluminum Hydroxide Clusters with Trisilanols during Speciation in Aluminum(III)–Water Systems: Reproducible, Large Scale Access to Molecular Aluminate Models

Modern concepts and methods in the chemistry of polyhedral metallasiloxanes

Synthesis and structure of sterically overloaded tetra-coordinated yttrium and lanthanum disiloxides

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