作者:Frank Riedmiller、Hubert Schmidbaur
DOI:10.1039/b004024j
日期:——
Treatment of 2-bromo- or 2,5-dibromo-thiophene with equivalent quantities of n-butyllithium at low temperature, followed by bromogermane, afforded 2-germyl- 2 and 2,5-di(germyl)-thiophene 3 in 44 and 82% yields, respectively. The in situ Grignard reaction of 2-bromothiophene with tetra(ethoxy)germane and magnesium gave low yields of 2-[tri(ethoxy)germyl]thiophene 1. Attempts to convert this product into the trihydride using LiAlH4 yielded only traces of 2. Bis(2-thienyl)germane 4 is available from 2-lithiothiophene and dibromogermane (molar ratio 2∶1, 64% yield). The products have been characterized by analytical and spectroscopic methods. The 73Ge NMR spectra show only broad resonances without discernible 73Ge–1H coupling owing to the low symmetry of the substituents. The molecular geometries of 2 and 3 have been calculated using standard ab initio quantum chemical methods. The results are similar to those for analogous silylthiophenes reported recently. There is no evidence for significant intramolecular Ge⋯S interactions.
将2-溴或2,5-二溴噻吩在低温下与等量的正丁基锂反应,然后加入溴基锗,分别获得2-锗基-2和2,5-二(锗基)-噻吩,产率为44%和82%。2-溴噻吩与四乙氧基锗和镁的原位格氏反应仅得到了低产率的2-[三(乙氧基)锗基]噻吩。尝试使用LiAlH4将该产物转化为三氢化物,仅得到微量的2。二(2-噻吩基)锗可通过2-锂噻吩与二溴锗反应获得(摩尔比2:1,产率64%)。产品已通过分析和光谱方法进行表征。73Ge NMR光谱显示只有宽共振,没有可辨别的73Ge–1H耦合,这是由于取代基的低对称性。2和3的分子几何结构已使用标准的从头算量子化学方法计算,结果与最近报告的类似硅噻吩的结果相似。没有证据表明存在显著的分子内Ge⋯S相互作用。