Cyclic diboranes(4) based on a chelating monoanionic benzylphosphine linker were prepared through boron–silicon exchange between arylsilanes and B₂Br₄. Coordination of Lewis bases to the remaining sp² boron atom yielded unsymmetrical sp³‐sp³ diboranes, which were reduced with KC₈ to their corresponding trans‐diborenes. These compounds were studied with a combination of spectroscopic methods, X‐ray diffraction, and DFT calculations. PMe₃‐stabilized diborene 6 was found to undergo thermal rearrangement to gem‐diborene 8. DFT calculations on 8 reveal a polar boron–boron bond, and indicate that the compound is best described as a borylborylene.

中文翻译：

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不对称的环状二硼烷和热重排成硼烷基硼烯

通过芳基硅烷和B ₂ Br ₄之间的硼-硅交换，制备了基于螯合单阴离子苄基膦连接基的环状乙硼烷（4）。Lewis碱与剩余的sp ²硼原子的配位产生不对称的sp ³ -sp ³乙硼烷，并随KC ₈还原为相应的反式-diborenes。通过光谱方法，X射线衍射和DFT计算相结合的方法对这些化合物进行了研究。发现PMe ₃稳定的二硼烷6发生了热重排，变为gem- diborene 8。DFT计算8 揭示了硼-硼的极性键，并表明该化合物最好地描述为硼基硼烯。