Germanium derivatives

The preference for formation of dihalocarbenes (but not the trihalomethyl radicals) upon thermolysis of trihalomethyl mercury, silicon and germanium derivatives seems to be a result of intermolecular coordination, of type [1], and of a thermodynamic preference for the carbene-forming pathway. The... 

Germenes and germaphosphenes can be reduced with lithium aluminum hydride to give the corresponding germanes. This reaction apparently has not been examined for other unsaturated germanium derivatives. 

The germanium derivative of cysteine Ge[SCH2CH(NH2)COOH]4 shows low toxicity in acute (3402 mg kg-1), subacute and chronic experiments53. No teratogenic effects were noticed in rats and mice after subcutaneous administration of the compound54. 

Similar intramolecular cycloadditions are encountered where an ether linkage has been incorporated into the met a or para linking groups 123. In these cyclizations the better yields were obtained from the para-attached systems. The yields obtained are again dependent on the chain length of the separator and are indicated below the appropriate structures (124)57. Other hetero-atom-substituted cyclophanes (125) can be obtained by irradiation of the divinyl compounds (126)58,59. The use of tin and germanium derivatives... 

In conclusion we can predict that the next review on low coordinate germanium will describe some triply bonded germanium derivatives. 

This type of reaction also occurs with germanium derivatives ... 

The germacyclopentadienide anions present structures consistent with substantial localization of the negative charge on germanium unlike silicon (vide supra)-, germole dianions would be reasonable candidates for stable aromatic germanium derivatives. 

The p-RgPBsHg compounds discussed above apparently do not isomerize to the corresponding 2-substituted derivatives as the silicon and germanium derivatives do. This is not unexpected in view of the fact that the bridging phosphino-group is connected to the two basal borons by two 2-center two electron bonds as opposed to the one 3-center two electron bond which presumably binds the Group IV moieties previously discussed. 

Trimethylgallium, unlike the alkyl silicon and germanium derivatives, is extremely reactive at ambient temperatures, and, unlike its aluminium counterpart, is a monomer at room temperature or higher. It reacts with the surface silanols according to main reaction (BB). 

Thirty-eight years after Winkler developed the organozinc method for the synthesis of tetraethylgermane, Dennis and Hance160 reproduced it, but this method for synthesis of aliphatic germanium derivative was not used later. However, in the years 1927-1935 arylzinc halides were used for the synthesis of tetraarylgermanes23,161-165. 

Hypervalent germanium derivatives are compounds having penta-, hexa- and sometimes heptacoordinate germanium atom. Numerous publications are devoted to inorganic and pseudo-organic (with no C—Ge bonds) derivatives of this type159,488,518,524-528. 

Laboratory research on organic compounds of the silicon subgroup elements showed that they ought to be divided into two subgroups (dyads) in accordance with their similarity in chemical properties and biological activity. Silicon and germanium derivatives were placed in the first one while the tin and lead derivatives belong to the second. 

When the same reaction was conducted with two equivalents of w-BuLi followed by alkylation with Mel, it gave the expected dimethylated germanium derivative almost quantitatively. However, the reaction mechanism might be more complex than the expected nucleophilic substitution by a germanium-centered dianion. A more complex radical... 

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