Alkoxides containing alkali metal

Two principle strategies have been employed for the synthesis of siloxide-containing molecular precursors. The first involves a silanolysis, or condensation, reaction of the Si - OH groups with a metal amido, alkyl, hahde, or alkoxide complex. The second method involves salt metathesis reactions of an alkali metal siloxide with a metal hahde. Much of our work has been focused on formation of tris(tert-butoxy)siloxide derivatives of the early transition metals and main group elements. The largely imexplored regions of the periodic table include the lanthanides and later transition metals. 

The most usual synthetic routes to the derivatives of platinum group metals are the exchange reactions of the complexes containing halide ligands with alkali metal alkoxides (method 5), alcoholysis of the same kind derivatives (usually by phenols, method 4), alcoholysis of hydroxide complexes (method 3), and redox reactions — reduction of chlorides or 0s04 in alcohol media (method 7) (Table 12.25). 

The reaction of Rh6(CO)i6 with a primary amine gives the monoanionic derivative containing a carboamide group, whereas the analogous carbo-alkoxy derivatives have been obtained by reduction with alkali metal alkoxides in anhydrous alcohol (45) ... 

Single metal and mixed metal oxo alkoxides can also be prepared by reaction between metal halides, oxy halides, and alkali metal alkoxides.47,48 One of the first to be structurally characterized was a series of mixed Cd or Sn containing zirconium, tin, and titanium alkoxides.84,85 These and other examples are shown in skeletal form in Figure 3. 

Similar block copolymers have also been prepared by coupling methyl methacrylate macroanions and suitably terminated poly(ethylene oxide)( )and by the initiation of methyl and ethyl methacrylate by alkali metal alkoxides of poly(ethylene oxide)( 3). styrene containing block copolymers have also been produced( ). In the former plus latter techniques the ester containing block segments were subsequently hydrolyzed to methacrylic acid thus making them water soluble. 

In the absence of a solvent and excess of chloral, the reaction rate for this reaction may be expressed by a third-order equation-second order with respect to dimethyl H-phosphonate and first order with respect to the chloral [177]. In dioxane solution and excess dimethyl H-phosphonate, the dependence of the reaction rate on the chloral concentration is the same. In addition to the chloro-containing a-hydroxyalkyl phosphonate, which is the main product under the above conditions, a side product formed as a result of dehydrochlorination of the main product, followed by phosphonate-phosphate rearrangement, has been also isolated. The presence of a base such as triethylamine, alkali metal alkoxides and hydroxides, or sodium carbonate accelerates the dehydrochlorination process. An example of this side reaction is the transformation of dialkyl-2,2,2-trichloro-l-hydroxyethyl phosphonates into dialkyl-2,2-dichlQrovinyl phosphates in the presence of sodium hydroxide [181,182]. 

In this book all these types of compounds will be considered, even though some, e.g. alkali metal amides and alkoxides, might not contain direct metal-carbon bonds. This is line with other books of organometallic chemistry (e.g. the multivolume treatise Comprehensive Organometallic Chemistry) which includes such... 

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