Alkoxides reagents

Manipulation of the factors noted above may be used to control the characteristics of the hydrolysis and condensation reactions, which will dictate precursor nature. These reactions have been studied extensively for silica,1,63 and some similarity in chemical behavior to electronic material systems (PZT, etc.) has been noted because of the alkoxide reagents used in the synthesis of these material systems.52,70,71... 

Routes to monomeric , mononuclear , monolanthanide alkoxides, enolates, siloxides and aryloxides - an expanded title which will put the scope of the article in a more concrete form. The synthesis of mononuclear alkoxides, in particularly homoleptic derivatives [1], was decisively stimulated by the discovery of high temperature superconducting ceramics based on YBa2Cu307<, where yttrium represents the lanthanide elements [2]. The support of volatile and highly soluble molecular precursors is a prerequisite for synthesizing thin films of these materials by means of MOCVD [3] and sol gel processes [4], respectively. More recently, lanthanide alkoxide reagents became established in... 

Coupling of functional groups onto the walls of mesoporous silica materials can also be achieved by surfactant-templated assembly of an organosilicon alkoxide and silicon alkoxide reagents. Recent reports that use this synthetic strategy include hybrids of methacrylate-mesoporous silica [104], phenyl-amino (thiol or allyl)-mesoporous silica [105], and organic chromo-phore-mesoporous silica [106]. 

Which do we choose As always, we must consider the danger of elimination competing with the desired substitution elimination should be particularly serious here because of the strong basicity of the alkoxide reagent. We therefore reject the use of the tertiary halide, which we expect to yield mostly—or all—elimination product we must use the other combination. The disadvantage of the slow... 

Our work is devoted to the investigation of several parameters in sol-gel syntheses from alkoxide reagents. A better understanding of the chemical processes that take place in the earliest stages of sol-gel preparation can provide a potential better control of the microstructural evolution of a catalyst, in terms of chemical homogeneity and textural properties. 

Factors influencing these reactions include the type of alkoxide reagents, the types of solvents and catalysts, the concentration, and the reaction temperature [6]. In practice, these factors affect each other in complicated ways, and ensuring that these reactions proceed ideally is not easy. 

With an alkoxide reagent, things are different. Now the product is not a carboxylic acid but another ester. There is no proton that can be removed, and there is a new molecule of alkoxide generated. The reaction is approximately thermoneutral. The reaction is reversible. 

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