Diborane(4) compounds are versatile reagents in synthetic chemistry. Generally, diboranes(4) with sp²-hybridized boron atoms react as electrophiles. By contrast, the chemistry of nucleophilic diborane(4) compounds with two sp³-hybridized boron atoms is very much underdeveloped. In this work, we systematically vary the substituents of electron-rich diborane(4) compounds with bridging guanidinate substituents. In this way, five new diboranes are synthesized and fully characterized. Using quantum chemical computations, we show that the electronic properties and reactivity of these compounds can be rationally varied by the choice of substituents. The HOMO energies, adiabatic ionization energies and proton affinities are considered as parameters to compare the chemical properties of these unusual compounds.

中文翻译：

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调谐的富电子的乙硼烷（4）的化合物的亲核与通过取代桥接胍基的取代基†

乙硼烷（4）化合物是合成化学中的多用途试剂。通常，具有sp ^2-杂化的硼原子的乙硼烷（4）作为亲电试剂反应。相比之下，具有两个sp ³的亲核乙硼烷（4）化合物的化学性质-杂化的硼原子非常不发达。在这项工作中，我们系统地改变具有桥联胍基取代基的富电子二硼烷（4）化合物的取代基。以此方式，合成了五个新的乙硼烷并对其进行了充分表征。使用量子化学计算，我们表明，通过选择取代基，可以合理地改变这些化合物的电子性质和反应性。将HOMO能量，绝热电离能和质子亲和力作为参数来比较这些不寻常化合物的化学性质。