Germanium organometallic compounds

The application of these techniques has led to the discovery of a number of organometallic species of arsenic, tin, and antimony in the marine environment. Germanium has not been observed to form organometallic compounds in nature. Some aspects of the geochemical cycles of these elements which have been elucidated by the use of these methods are discussed. 

It is somewhat disappointing to realize that the thermochemistry of germanium, tin and lead organometallic compounds is still at the level achieved ten years ago, in contrast to the considerable recent efforts to probe the energetics of the silicon analogues. The data analysis in the previous sections shows that many key values are either missing or require experimental confirmation. To a certain extent, an overall discussion of the thermochemical data for Ge, Sn and Pb is therefore hindered by the probable inaccuracies and the uncertainties that affect those values. 

Germanium in organometallic compounds can be determined by a modification of the combustion tube method. The sample is mixed with a large excess of chromic oxide, the organic elements are burnt in the tube and are absorbed downstream, whereas the... 

It is now well established that organometallic compounds are formed in the environment from mercury, arsenic, selenium, tellurium and tin and hence were also deduced on the basis of analytical evidence for lead, germanium, antimony and thallium. Biological methylation of tin has been demonstrated by the use of experimental organisms. Methylgermanium and methyllead were widely found in the environment but it is debatable whether germanium and lead are directly methylated by biological activity in natural environment. 

As was the case with the volume The chemistry of organic arsenic, antimony and bismuth compounds, published in 1994, it was clear that the set of five volumes describing organometallic compounds (edited by Professor Frank R. Hartley) did not deal in sufficient depth with organic compounds of germanium, tin and lead. Hence we decided to publish the present volume, which we hope will be a useful and worthwhile addition to the series The Chemistry of Functional Groups. In this volume the authors literature search extended in most cases up to the end of 1994. 

Germanium also forms organometallic compounds. Over two hundred have been reported, from chloromethyl trichlorogermane. CICH-GeCF to cyclnleirakis (diphenyl germnnoxanel. [(CsHOiGeOJa. 

A thermographic material with only one heat-sensitive component is prepared by reaction of an organometallic compound such as phenylmercury(II) nitrate with a thiourea derivative.230 The product is ball milled and coated in a binder such as poly(vinyl acetate). Other organometallic compounds disclosed are those of bismuth, tin, gallium and germanium combined with a variety of sulfur-containing compounds such as thioamides and xanthates. 

Classes of organic compounds analysed by this technique include non ionic surfactants, fatty acids, hydrocarbons (all types), organochlorine compounds, organosulphur and phosphorus compounds, substituted aromatic compounds, NT A, EDTA and insecticides and herbicides. Organometallic compounds studied include those of arsenic, lead, germanium, mercury and tin. 

P. G. Harrison, Organometallic Compounds of Germanium. Tin and Lead, Chapman Hall, London, 1985, p. 192. 

In the following we review quantum chemical work about organic germanium, tin and lead compounds which has been published since 1990. The presentation of the results is organized as follows. First, we discuss in brief some relevant theoretical work about parent compounds of Ge to Pb. Then we summarize calculations of organometallic compounds. The latter section is divided into studies of neutral closed-shell molecules, charged species and radicals. E is used for any of the group-14 elements C to Pb. 

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