Organoaluminum halide

More complex mixed metal fluorides of the type [( -C5Me5)MMeF]-[Me2AlF2] 2, with M = Zr and Hf have been prepared and structurally characterized [68], These can be regarded as supermolecules self-assembled via fluorine bridges, 33. 

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No reaction occurs when triethylaluminum, aluminum chloride, stannic chloride, titanium tetrachloride, diethylzinc or triethylboron are used in lieu of an organoaluminum halide or sesquihalide. 

In later communications (27, 28) Hirooka reported that in addition to acrylonitrile, other conjugated monomers such as methyl acrylate and methyl methacrylate formed active complexes with organoaluminum halides, and the latter yielded high molecular weight 1 1 alternating copolymers with styrene and ethylene. However, an unconjugated monomer such as vinyl acetate failed to copolymerize with olefins by this technique. 

Although the yield of copolymer is higher when the organoaluminum halide is used as catalyst in lieu of the peroxide, the combination of the two gives a 3-5 times higher yield. However, since the product is essentially the same 1 1 copolymer in either case, as compared with the entirely... 

The direct interaction of Al, H2, and olefin (hydroalumination) is used to give either the dialkyl hydrides or the trialkyls. These are also accessible by reduction of organoaluminum halides and exist as dimers or trimers, depending on the steric requirements of the alkyl or aryl group. Examples are [Bu2A1H]3, [mes AlH2]2, and mes GaH2.24... 

The sttuctures of organoaluminum halides R AlXs are dominated by dimeric structures with AI2X2 four-membered rings for X = Cl, Br, and I. Unlike the aluminum alkyls, these hahde bridges are electron-precise and result from intermolecular Lewis acid-base complexation. These dimers do dissociate and readily react with Lewis bases, but the enthalpies of dissociation are higher than those for the aluminum alkyls. In many cases, the strength of the association is sufficient that dimers are observed in the gas phase. 

The copolymerization of a donor monomer with a weaker acceptor monomer, such as methyl methacrylate or acrylonitrile, in the presence of a complexing agent (a metal halide or an organoaluminum halide) yields an equimolar, alternating copolymer, regardless of initial monomer charge and with or without free-radical precursor (1). 

The dehalogenation of organoaluminum halides with active metals, such as Na, K is is still of importance considering the easy access to the organoaluminum sesquihalides (see 5.3.3.2.2)i E... 

From attempts to use organoaluminum halides to circumvent olefin elimination and hydrometallation in the presence of Ti or Zr compounds, the use of C—Al bonds in carbometallations may gain importance. 

Silyl-alkali-metal reagents with Al metal and organoaluminum halides lead to silyl-Al compounds. The best results are, e.g., using K[SiHj] with n-BujAlCl in... 

The rate of polymerization of polar monomers, for example, maleic anhydride, acrylonitrile, or methyl methacrylate, can be enhanced by coraplexing them with a metal halide (zinc or vanadium chloride) or an organoaluminum halide (ethyl aluminum sesqui-chloride). These complexed monomers participate in a one-electron transfer reaction with either an uncomplexed monomer or another electron-donor monomer, for example, olefin, diene, or styrene, and thus form alternating copolymers (11) with free-radical initiators. An alternating styrene/acrylonitrile copolymer (12) has been prepared by free-radical initiation of equimolar mixtures of the monomers in the presence of nitrile-coraplexing agents such as aluminum alkyls. 

The action of alkyl halides on metallic aluminum leads to organoaluminum halides 233... 

Organoaluminum halides, obtained as above, can also be converted into tri-alkylaluminums by reduction with alkali metals and, conversely, alkylaluminum chlorides can be obtained from trialkylaluminums and aluminum chloride.236... 

Organoaluminum halides can be used to prepare pseudohalide derivatives, such as azides and cyanides, by salt metathesis. Azides are prepared by trimethylsilylhalide elimination (equation 14) and by reaction of a trialkylaluminum with chloroazide, CIN3. Organoaluminum cyanides have also been prepared by reactions of a trialkylaluminum with HCN (equation 15). ... 

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