Abstract
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.
Published Version
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