Oxygen-aluminum bonds

The driving force for this reaction is the strength of the aluminum-oxygen bond relative to the aluminum-nitrogen bond. This reaction provides a good way of making synthetically useful amides of /V - in c th o x y - /V - m c th y I a in i n c.134 Trialkylamidotin and bis(hexamethyldi-... 

In the third chapter Wheatley and Linton describe new developments in the remarkable chemistry of aluminum and oxygen. While compounds featuring an aluminum-oxygen bond find widespread utility (as catalyst supports and co-catalysts, for example) there is still a great deal that is not understood in how these compounds form. This chapter provides the necessary basic information upon which further applications may be developed. 

Strong mineral acids react with clays to hydrolyze aluminum-oxygen bonds. The aluminum dissolves, leaving an altered structure. Protons in the acid also exchange with sodium and other alkali cations, leaving an acidic material. Houdry took advantage of such reactions in making the active acidic catalysts... 

Treatment of the reaction mixture with aqueous acid cleaves the aluminum-oxygen bond and produces cyclohexanol. 

The amphoterism and facile hydrolysis of hydrates of aluminum salts make it impossible to prepare anhydrous salts by dehydration. For example, the strength of the aluminum-oxygen bond in [Al(H20)6]Cl3 precludes the formation of A1 Cl bonds and AI2O3 is obtained upon heating (equation 7). 

Calculations have revealed the critical influence of the aluminum substituents. Significantly lower activation barriers are predicted for trialkoxides relative to the corresponding monoalkoxides [66]. The sensitivity of aluminum initiators toward steric bulk has also been noted and is attributed to the shortness of the aluminum-oxygen bonds [67]. Accordingly, the activation barrier for the insertion step is found to be about 40% higher for lactide than for glycolide for the... 

The driving force for this reaction is the greater strength of the aluminum-oxygen bond relative to the aluminum-nitrogen bond. Trialkyltin amides and tetrakis(dimethylamino)titanium show similar reactivity. 

The aluminum alkoxide-initiated polymerization of lactones such as CL and DXO proceeds by a coordination-insertion mechanism, which involves acyl-oxygen bond cleavage of the monomer and insertion into the aluminum-oxygen bond of the initiator. The coordination of the exocycHc oxygen to the metal results in polarization, which in turn makes the carbonyl carbon of the monomer more... 

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