- Photodecompostion of the Oligogermanes nBu3GeGePh2GenBu3 and nBu3GeGePh3: Identification of the Photoproducts by Spectroscopic and Spectrometric Methods
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The oligogermane nBu3GeGePh2GenBu3was photolyzed using UV-C light in the presence of acetic acid as a trapping agent and the photoproducts were identified using1H NMR spectroscopy, gas chromatography/electron-impact mass spectrometry, and high resolution accurate mass mass spectrometry. The products identified were the germanes nBu3GeH, nBu3GeOAc, and Ph2Ge(H)OAc (OAc = C2H3O2) and the digermane nBu6Ge2. This indicates that both germanium–germanium single bonds are cleaved homolytically upon irradiation to generate two nBu3Ge·radicals and the germylene Ph2Ge:. The digermane nBu3GeGePh3was also photolyzed under identical conditions, and in this case the photoproducts were identified as nBu3GeH, nBu3GeOAc, Ph3GeH, Ph3GeOAc and the digermanes nBu6Ge2and Ph6Ge2.
- Komanduri, Sangeetha P.,Schrick, Aaron C.,Feasley, Christa L.,Dufresne, Craig P.,Weinert, Charles S.
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p. 3196 - 3203
(2016/07/14)
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- Tributylgermanium hydride as a replacement for tributyltin hydride in radical reactions
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Tributylgermanium hydride (Bu3GeH) can be used as an alternative to tributyltin hydride (Bu3SnH) as a radical generating reagent with a wide range of radical substrates. Tributylgermanium hydride has several practical advantages over tributyltin hydride, e.g. low toxicity, good stability and much easier work-up of reactions. The reagent can be easily prepared in good yield and stored indefinitely. Suitable substrates include iodides, bromides, activated chlorides, phenyl selenides, tert-nitroalkanes, thiocarbonylimidazolides and Barton esters. Alkyl, vinyl and aryl radicals can be generated in radical reactions including reduction and cyclisation processes. Common radical initiators such as ACCN and triethylborane can be used. The slower rate of hydrogen abstraction by carbon-centred radicals from Bu 3GeH as compared to Bu3SnH facilitates improved cyclisation yields. Polarity reversal catalysis (PRC) with phenylthiol can be used in reactions which generate stable radical intermediates which will not abstract hydrogen from Bu3GeH.
- Bowman, W. Russell,Krintel, Sussie L.,Schilling, Mark B.
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p. 585 - 592
(2007/10/03)
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- Cp2TiCl2 catalyzed one-pot synthesis of n-Bu3GeH from GeCl4
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The reaction of GeCl4 with n-BuMgCl in presence of a catalytic amount of Cp2TiCl2 gives n-Bu3GeH and n-Bu4Ge in ca. 70 and 25% yield, respectively. This method provides an industrially feasible one-pot synthesis for Bu3GeH and Bu4Ge. The reaction temperature and stoichiometry seem to be important in the distribution of the products. Apart from elemental analysis these compounds have been characterized by comparing their boiling points, NMR spectral data and GC assay with that of the authentic samples.
- Colacot, Thomas J.
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p. 378 - 381
(2007/10/03)
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- Reactivity of dianionic hexacoordinate germanium complexes toward organometallic reagents. A new route to organogermanes
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Lithium and potassium tris(benzene-1,2-diolato)germanates (2a and 2b, respectively) and potassium tris(butane-2,3-diolato)germanate (3) are easily prepared from GeO2 in quantitative yields. They are very reactive toward organometallic reagents, the reactivity depending on the ligands on the germanium. Complexes 2 react with an excess of Grignard reagent to give the corresponding tetraorganogermanes R4Ge while the less reactive complex 3 leads to the functional triorganogermanes R3GeX. Tetraorganogermanes can also be prepared from complex 2b by reaction with organic bromides in the presence of Mg (Barbier reaction). The influence of Cp2TiCl2 and MgBr2 on the reactivity of Grignard reagents with these complexes was also investigated: in both cases formation of triorganogermanes was favored.
- Cerveau,Chuit,Corriu,Reyé
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p. 1510 - 1515
(2008/10/08)
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