Reaktion lithiumorganischer Verbindungen mit Siliciumdioxyd

Boehm, H. P.; Schneider, Manfred; Wistuba, H.

doi:10.1002/ange.19650771415

Cited by 14 publications

(3 citation statements)

References 3 publications

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“…It was found, however, that replacement of surface hydroxyl by chlorine is not necessary. Lithium organic compounds are powerful nucleophilic agents which are able to open up siloxane bonds [703] \ -Si-O-Li+…”

Section: D) Chemical Reactions With Anchored Functional Groupsmentioning

confidence: 99%

Nature and Estimation of Functional Groups on Solid Surfaces

Boehm

Knözinger

1983

Catalysis

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Section: D) Chemical Reactions With Anchored Functional Groupsmentioning

confidence: 99%

Nature and Estimation of Functional Groups on Solid Surfaces

Boehm

Knözinger

1983

Catalysis

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“…The authors found doubly or triply alkylated surface silicon atoms in the material in addition to the desired monoalkylated silicon atoms, as shown by 29 Si-magic-angle spinning (MAS) NMR. To overcome these problems and to create a fast and economically attractive modification technique, Lim et al and our group have independently developed a method to modify mesoporous silica materials in one-pot reactions. , The main aspect of the reaction, the direct conversion of surface silicon atoms in silica with a metalorganic reagent, has been reported long ago for the case of fumed silica by Kautsky and Bartocha and by Boehm et al in 1955 and 1965, respectively. , They observed a direct conversion of silicon surface atoms by metalorganic compounds such as Grignard or organolithium compounds. The reaction is based on a direct attack of the nucleophile at the silicon atom of a siloxane bridge.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Reaction Conditions for the Metalorganic Modification of MCM-41

2007

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The modification of periodic mesoporous silica with organic groups following an optimized metalorganic route is described. Organolithium and Grignard reagents (n-butyllithium and allyl-magnesium bromide) were used to directly substitute silicon atoms with organic moieties in the channel walls of the silica host. A detailed study of several representative reactions with respect to reaction parameters, that is, reaction temperature, reaction time, and reagent concentration, shows that the degree of surface substitution can be controlled within a broad range and up to very high levels while still maintaining the integrity of the ordered silica host. The functionalized mesoporous materials can also retain high surface areas and pore volumes. Furthermore, the reactions can be performed at low temperatures compared to the more traditional grafting techniques on the basis of organosilanes.

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“…9,10 This method is based on the direct metalorganic surface modification of mesoporous silica materials using Grignard or organo-lithium compounds. First attempts in this field were presented in 1955 by Kautsky and Bartocha and in 1965 by Boehm et al 11,12 The materials resulting in the early studies were mainly organosilanes and polyorganosilanes. Further studies were reported by Yamamoto and Tatsumi who esterified the silica material with alcohols before performing conversion with metalorganic compounds.…”

Section: Introductionmentioning

confidence: 99%

Sequential transformations of organic nitrogen functionalities in periodic mesoporous silica

2008

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New methods for the sequential organic functionalisation of periodic mesoporous silica materials have been established. In a first step, organic-inorganic hybrid materials were synthesized by direct substitution at the silicon atoms of the channel structure with metalorganic reagents such as lithiated aromatics. The resulting nitrogen-containing nanostructured hybrid materials were subsequently converted in a second step by reactions such as azo-coupling and the Meerwein-Schuster reaction, respectively. These efficient and economic reactions lead to the formation of complex organicinorganic hybrid materials with new functionalities, including quaternized ammonium salts, aromatic imines and peptides, as well as azo-compounds and stilbenes. The new nanostructured materials were characterized with a comprehensive set of structural and spectroscopic methods, including X-ray diffraction, thermoanalysis, nitrogen sorption, as well as Raman, IR, UV-vis and solid-state NMR spectroscopy.

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Reaktion lithiumorganischer Verbindungen mit Siliciumdioxyd

Cited by 14 publications

References 3 publications

Nature and Estimation of Functional Groups on Solid Surfaces

Nature and Estimation of Functional Groups on Solid Surfaces

Optimization of Reaction Conditions for the Metalorganic Modification of MCM-41

Sequential transformations of organic nitrogen functionalities in periodic mesoporous silica

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