General characteristic of the metal alkoxides

The M(OR) derivatives are known now for almost all the elements of the Periodic Table (including the transuranium elements and Xenon). They are formal analogs of hydroxides but possess much higher thermal stability. Their properties are determined not only by the electronegativity of the metal atom but also by the nature of the radical — its ramification and the acidity of the corresponding alcohol, which provides their various properties. From this point of view they can be subdivided into the following groups of compounds  

Special interest has recently been given to the metal 2-alkoxyethoxides, M(OC2H4OR)Il (R= Me, Et) — derivatives of the monoethers of ethyleneglycol. The presence of the second ether function in the molecule permits formation of chelate cycles  

The numerous reactions of metal alkoxides can be subdivided into three major groups (1) complex formation with donor ligands or alkoxides of other 

The numerous substitution reactions lay in the background of the application of metal alkoxides in inorganic and metal-organic synthesis (preparation of halides, hydrides, sulfides, carboxylates, alkyl derivatives, certain classes of coordination compounds, etc.). One advantage of their application is the formation of only alcohols as by-products  

The products of partial substitution for the OR-groups, i.e., alkoxocarbox-ylates, P-diketonates M(OR)mX , where X= RCOO, acac, thd, etc.—the mixed-ligand complexes—usually are more soluble and stable than M(OR) , as their molecules contain the chelate cycles. Mehrotra et al. [223] have described a great number of such products (usually liquid or amorphous), in which individuality appeared sometimes questionable. During recent years, however, in connection with the application of these compounds to the synthesis of oxides, interest in them has increased, and a number of them have been isolated and structurally characterized (Chapter 7). Unfortunately, length restriction did not permit us to present a complete review of their chemistry in this book. 

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