Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg (Germany).
Anorganische Chemie, Bergische Universität Wuppertal, Gaussstrasse 20, 42119 Wuppertal (Germany).
Angew Chem Int Ed Engl. 2015 Sep 14;54(38):11259-64. doi: 10.1002/anie.201504579. Epub 2015 Jul 27.
Diborane(6) dianions with substituents that are bonded to boron via carbon are very reactive and therefore only a few examples are known. Diborane(6) derivatives are the simplest catenated boron compounds with an electron-precise B-B σ-bond that are of fundamental interest and of relevance for material applications. The homoleptic hexacyanodiborane(6) dianion B2 (CN)6 that is chemically very robust is reported. The dianion is air-stable and resistant against boiling water and anhydrous hydrogen fluoride. Its salts are thermally highly stable, for example, decomposition of (H3 O)2 [B2 (CN)6 ] starts at 200 °C. The B2 (CN)6 dianion is readily accessible starting from 1) B(CN)3 (2-) and an oxidant, 2) BF(CN)3 and a reductant, or 3) by the reaction of B(CN)3 (2-) with BHal(CN)3 (Hal=F, Br). The latter reaction was found to proceed via a triply negatively charged transition state according to an SN 2 mechanism.
带有通过碳键合到硼的取代基的二硼烷(6)二阴离子非常活泼，因此仅已知少数几个例子。二硼烷(6)衍生物是具有电子精确 B-B σ 键的最简单的链状硼化合物，它们具有基础性的兴趣并且与材料应用有关。报道了化学性质非常稳定的同核六氰合二硼烷(6)二阴离子B2(CN)6 。该二阴离子在空气中稳定，并且能够耐受沸水和无水氟化氢。其盐具有很高的热稳定性，例如，(H3O)2[B2(CN)6]的分解在 200°C 才开始。B2(CN)6 二阴离子可以通过以下方法轻易获得：1）B(CN)3(2-)和氧化剂，2）BF(CN)3 和还原剂，或 3）B(CN)3(2-)与BHal(CN)3 （Hal=F，Br）反应。根据 SN2 机理，发现后一种反应通过三重带负电荷的过渡态进行。
