Gallium trialkyls

Bidentate coordination leading to bis-adducts is observed in reactions of distibines with aluminium or gallium trialkyls in absence of solvent at low temperatures (Equation 2).76... 

No monomeric alkali metal alkyls or aryls are known, as those crystal structures which have been determined indicate electron-deficient, e.g. (MeLi), or ionic (K Me ) constitutions. The dialkyls of the lighter second group metals are mostly electron-deficient dimers or polymers, but those of zinc, cadmium and mercury are monomers with a linear structure as expected from participation of one (metal) s and one p orbital (with or without dji participation). In the third group the pattern is more complex. Whereas the trialkylboranes are monomeric, boron hydrides (and alkyl hydrides) and polyboron compounds form electron-deficient structures. Aluminium alkyls and alkyl hydrides are normally electron-deficient dimers or trimers gallium trialkyls are monomeric though the trivinyl is a dimer trimethylindium is a weakly associated tetramer in the solid state, otherwise all indium and thallium trialkyls appear to be monomers. 

Reactions with the trialkyls of aluminium, gallium and indium are proceeding without eomplications as well 39) ... 

The purification of the gallium salt solutions is carried out by solvent extraction and/or by ion exchange. The most effective extractants are dialkyl-phosphates in sulfate medium and ethers, ketones (qv), alcohols, and trialkyl-phosphates in chloride medium. Electrorefining, ie, anodic dissolution and simultaneous cathodic deposition, is also used to purify metallic gallium. 

M, Roesky. H. W. Reactions of trialkyl phosphates with trialkyls of aluminum and gallium New route to alumino- and galtophos-phate compounds via dealkyIsilyfation. Organometallics 1999, 18, 523-52B. 

Since the boroxines are readily available from B203 and trialkyl boranes or trialkoxy boranes, they are in effect reactions of boron oxide with trialkyl alanes. Gallium tribromide and triethylalane give triethylgallane in over 80% yield, but only the first alkyl group on aluminum is involved in alkylation (63, 65) ... 

Indium halides behave similarly to gallium halides in their reaction with trialkyl alanes (65). 

Aluminum alkyls are stronger Lewis acids than the trialkyls of boron and gallium, and complex formation in the presence of Lewis bases is an important aspect of the reaction chemistry of organoaluminum compounds. The Lewis acidity of organoaluminum compounds accounts for the strong association of aluminum alkyls and hydrides by three-center two-electron bonds, as well as association of organoaluminum... 

Phosphine oxide complexes with aluminium or gallium trimethyl can be made by direct addition to the etherate (9.159), while dimeric phosphinate complexes can be made by slowly adding a benzene solution of a phosphinic acid to a trialkyl aluminium (9.160, 9.161) [11,12]. Large cages are obtained in Equations 9.162 and 9.163 [13,14]. Compounds (9.164) have Ga-O-P linkages. 

Oxidative addition at electron-rich transition metal centers has been exploited as an alternative route to transition metal complexes of Group 13 ligands. Sources of the highly reactive 14-electron species [Pt(dcype)] react with gallium and indium trialkyls MR3 (M = Ga, In R = CH2 Bu, CH2SiMej) via oxidative addition of a M-C bond to give species of the form (dcype)Pt(R)(MR2) (43-46, Scheme 13.4) [219]. 

Whereas aluminium alkyls react with most hydroxy compounds (imless there are steric complications) with loss of all three alkyl groups, such reactions tend to stop after one or two alkyl groups have been eliminated from gallium and indium alkyls. Thallium trialkyls are hydrolysed only as far as R2TIOH, and to R2T1 cations in add solution (these are considered later). 

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