Beryllium alkyls

Because beryllium is a Lewis acid, it remains attached to ether that is the solvent in the reaction. Beryllium alkyls can also be produced by the reaction of the chloride with a lithium alkyl,... 

As is the case with numerous other metal alkyls, beryllium alkyls are spontaneously flammable in air. Beryllium oxide is produced, and it has a heat of formation of — 611kJ/mol. Dimethylberyllium also reacts explosively with water, and some of its other properties resemble those of trimethylaluminum. This should not be surprising because the metals have a strong diagonal relationship that relates to their similar charge-to-size ratios. 

Although the catalysts containing beryllium alkyl are more stereospeciflc than those with alkylaluminum (5, 6), nevertheless the greater part of our kinetic measurements were performed using alkylaluminum compounds, since they represent a special practical interest due to the higher availability, and lower toxicity compared with the corresponding beryllium compounds. 

The amount of amorphous polymer, which is generally produced in small percentage (9-16%) contemporaneously with the non-atactic polymer, is independent of reaction time (see Table II). It is on the contrary closely connected with the nature of the catalytic system employed and changes, for instance, when the triethylaluminum is substituted by other metal alkyls (beryllium alkyls, propylaluminum, isobutylaluminum, etc.) 5,28). It also depends on the purity of the a-titanium trichloride, in particular increasing in the presence of other crystalline modifications of titanium trichloride [i.e. -TiCU (27)] and of titanium compounds obtained by reduction of titanium tetrachloride at low temperature with aluminum alkyls. 

Common synthetic routes to beryllium amides, which were summarized in Ref. 1, involve the direct or indirect amination of beryllium hydride, beryllium chloride, a beryllium alkyl or amide precursor. Beryllium amides with bulky substituents are generally synthesized via the trans-metallation of beryllium dichloride with the lithium amides. The reaction of beryllium dichloride with secondary amines in the presence of an alkyllithium represents a less common synthetic route to beryllium amides. The formation ofbery Ilium amides via the reaction of an alkyl beryllium as well as beryllium hydride species with amines is also known. ... 

Be and Mg form an extensive range of organometallic compounds, those of Ca, Sr, and Ba being much more reactive and difficult to characterise. Beryllium alkyls such as Be(CH3)2 have chain structures with... 

Although beryllium alkyls can be obtained by the interaction of BeCl2 with lithium alkyls or Grignard reagents, they are best made in a pure state by heating the metal and a mercury dialkyl, for example ... 

The actual isolation of beryllium dialkyls in a pure state has only just been accomplished by Gilman and Schulze, and their work throws doubt upon the accurac of that of previous investigators. Their method of procedure is the one suggested by Krause and Wendt. In 1926, Durand claimed to have prepared beryllium methyl iodide, but the work has since been disproved by Gilman and Schulze. These workers have isolated beryllium alkyl halides by heating beryllium, alkyl halides, and ether in the presence of catalysts, such as mercuric chloride, beryllium chloride, or free bromine. The first aryl compound, beryllium phenyl iodide, has been prepared by a similar process. 

Electron donor-acceptor complexes of zinc, cadmium, mercury and beryllium alkyls... 

Other aliphatic caibanion structures associated with Group Ila cations are known. Some examples of these are dimethylbeiyllium and lithium tri-t-butyl beryllate. Since the beryllium alkyl carbanions have not yet been utilized as common synthetic reagents, diese structures will not be discussed further. 

Beryllium alkyls are polymeric. Magnesium forms Grignard reagents, which are useful in organic and organometallic synthesis. 

Beryllium alkyls and aryls are best made by reaction types 18.10 and 18.11 respectively. They are hydrolysed by water and inflame in air. 

Beryllium alkyls give colored complexes with 2,2 -bipyridine, for example, bipyBe(C2H5)2, which is bright red the colors of these and similar complexes13 with aromatic amines given by Be, Zn, Cd, Al and Ga alkyls are believed to be due to electron transfer from the M—C bond to the lowest unoccupied orbital of the amine. 

Reaction with beryllium alkyls 8, 4.6.4.1 Reaction with CuCb 8, 4.7.2.2.1 Reaction with Fe,(CO),/MeiAsNMei 8,... 

Only one bimetallic mechanism is presented here, as an example, the one originally proposed by Natta. He felt that chemisorptions of the organometallic compounds to transition metal halides take place during the reactions. Partially reduced forms of the di- and tri-chlorides of strongly electropositive metals with a small ionic radius (aluminum, beryllium, or magnesium) facilitate this. These chemisorptions result in formations of electron-deficient complexes between the two metals. Such complexes contain alkyl bridges similar to those present in dimeric aluminum and beryllium alkyls. The polymeric growth takes place from the aluminum-carbon bond of the bimetallic electron-deficient complexes . ... 

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