Year: 1968
Type: dissertation
Abstract: The first part of this thesis describes the alkylation of germanium halides by organoaluminium compounds, and comparison is made with other alkylating reagents.The second part presents the first detailed analysis of the mass spectra of a wide range of organogerrnanes, and shows how this technique can be used in characterising new compounds.Some aspects of infrared and proton magnetic resonance spectroscopy of organogermanium compounds are included.Part !.Chemical Studies.Besides giving good yields of the tetraorganogermanes, the reaction between alkylaluminium compounds and germanium tetrachloride gives by-products containing up to seven germanium atoms.With germanium di-iodide a complex mixture of compounds containing up to ten germanium atoms is obtained.These compounds are fully alkylated, having Me 3Ge end groups and the germanium skeleton is usually highly branched.In addition to these compounds, both reactions gave products resulting from growth of the alkyl group Wurtz reaction on Me 3 GeBr also gives organopolygermanes containing up to five germanium atoms and compounds with GeCH 2 Ge linkages.-5these preparations suggests that, by suitably adjusting conditions, they can be made to serve as a preparative method for the digermane, instead of the monogermane.6 7 This technique was recommended ' for the preparation of hexaphenyldigermane.Removal of ether from the mixture immediately after addition of Gecl 4 dissolved in toluene produced Ph 4 Ge; when the ether was left in the reaction mixture, Ph 6 Ge 2 resulted.This supports the existence of an R 3 GeMgX intermediate, since ether is well-known to be an essential part of Grignard reagents.8 A thorough study of the reaction between germanium tetrachloride and phenylmagnesium bromide led to the formulation of optimum conditions for digermane formation.The apparent relationship between yield of digermane and lack of experimental care was pinned down to the presence or absence of free magnesium as the real determining factor.(69%)This provided yet another suggestion for the formation of the germyl-Gtignard reagent: Ph 3 GeBr + Mg -~) Ph 3 GeMgBr so that the Ph 3 GeBr is to be regarded simply as a highly-branched alkyl halide, There ~¥as evidence that the finely divided magnesium not i i Only about 1% of Pr 6 Ge 2 was obtained from these Pr •MgX-GeX 4 systems, i but the system X=Cl also gave rise to Pr 8 Ge 4 .Some higher polymeric material was obtained, the proportion being higher for the iodide reaction, in accord with the benzylmagnesium bromide reactions already quoted.This polymeric material did, however, contain oxygen, and there was no evidence that Ge-Ge bonds were present.Earlier experiments 14 i i showed that the system Pr MgBr-GeBr 4 gave no Pr 6 Ge 2 , but some polymer was obtained which is probably analogous to that obtained in the other isopropyl systems, although it was assigned the composition (PriGe) .nThe formation of digermanes in reactions between Gecl 4 and mixedGrignard reagents has been studied 15 by adding a mixture of two alkyl halides and GeC1 4 to Mg in diethylether.It is interesting to note that reactions generally similar to those already discussed do take place, even though the Grignard reagent is not pre-formed.This means that if alkyl halides are eliminated in the formation of a germyl-Grignard reagent, as previously suggested, they may be removed by formation of further Grignard reagent.It is also worth noting that some trigermane was detected.Two possible routes to this are readily apparent:
Author: J. R. C. Light
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
Funder: Durham University
OpenAlex ID: W351621965