19089-95-3Relevant academic research and scientific papers
Preparation, Structure, and 73Ge NMR Spectroscopy of Arylgermanes ArGeH3, Ar2GeH2, and Ar3GeH
Riedmiller, Frank,Wegner, Gerald L.,Jockisch, Alexander,Schmidbaur, Hubert
, p. 4317 - 4324 (2008/10/08)
Arylgermanes of the types ArGeH3, At2GeH2, and Ar3GeH are important precursors for the preparation of oligo- and polygermanes. These precursors are readily prepared in good yields via an in situ Grignard reaction employing tetra(ethoxy)germane, an aryl halide, and magnesium metal in tetrahydrofuran as the reaction medium. The aryl-tri(ethoxy)germanes obtained were reduced to the germane hydrides with LiAIH4. This method is also applicable for aryl groups with sensitive substituents, as demonstrated for (4-methoxyphenyl)germane (p-anisylgermane, MeOC6H4GeHa). With modified stoichiometry, bis(p-anisyl)gennane is also available. The insertion of GeCI2 into the C-Br bond of arylbromides using catalytic amounts of anhydrous Aids proved to be an efficient alternative if the reaction was carried out in the absence of a solvent. After LiAlH4 reduction of the aryltrihalogermanes, phenyl-,p-tolyl-, and mesitylgermane were obtained in good yields. The arylgermanes have been identified by their analytical and spectroscopic data, including 73Ge (s = 9/2) NMR spectroscopy. Very surprisingly, sharp multiplet signals were observed with well-resolved 1J(Ge,H) couplings. The molecular structure of p-MeOC6H4GeH3 was determined from low-temperature X-ray diffraction data collected from a single-crystal grown "in situ" from the melt (mp: 15 °C). The significant distortions observed in the anisyl part of the structure and the conformation of the molecule are in excellent agreement with results of ab initio quantum chemical calculations (MP2/6-31G) of this compound.
Photoreaction of silyliron(II) complex Cp*Fe(CO)2SiMe3 (Cp* = η5C5Me5) in the presence of p-tolylgermane
El-Maradny, Amr,Tobita, Hiromi,Ogino, Hiroshi
, p. 4954 - 4958 (2008/10/09)
Photolysis of Cp*Fe(CO)2SiMe3 (3) in the presence of p-TolGeH3 (4) gave a mixture of cis and trans mono(germylene)-bridged diiron complexes, Cp*2Fe2(CO)2(μ-CO)(μ-Gep-TolH) (cis-5, trans-5), a mixture of two kinds of trans bis(germylene)-bridged diiron complexes, Cp*2Fe2(CO)2(μ-Gep-TolH)2 (syn-trans-6, anti-trans-6), and a complex with two Fe?H?Ge 3-center 2-electron bonds, Cp*2Fe2(CO)2(μ;-Gep-TolH 2)2 (7). A cis isomer of complex 6 (syn-cis(H)-6) was formed as the sole product by the thermolysis of complex 7. Photolysis of 7 or syn-cis(H)-6 resulted in the conversion to a mixture of syn-trans-6 and anti-trans-6. Reversible thermal and photochemical interconversion between cis and trans isomers of complex 5 was observed. The molar ratio of the cis and trans isomers of complex 5 in C6D6 was 7:93 at thermal equilibrium at 55°C and 84:16 at the photostationary state at 6°C.
Microwave-assisted Lewis acid catalysis: Application to the synthesis of alkyl- or arylhalogermanes
Laurent, Régis,Laporterie, André,Dubac, Jacques,Berlan, Jacques
, p. 2493 - 2495 (2008/10/08)
Under microwave irradiation, alkyl- or arylhalogermanes RnGeX4-n (R = Et, Bu, Ph; X = Cl, Br) are obtained by redistribution reactions of R4Ge with GeX4. These experimental conditions permit the synthesis of such compounds in good yield in a few minutes at atmospheric pressure. The direct Friedel-Crafts germylation of benzene and toluene by germanium tetrachloride also has been performed, but yields were low.
