Köppe R, Schnöckel H
Institute of Inorganic Chemistry , Karlsruhe Institute of Technology (KIT) , Engesserstr. 15 , 76131 Karlsruhe , Germany . Email:
Chem Sci. 2015 Feb 1;6(2):1199-1205. doi: 10.1039/c4sc02997f. Epub 2014 Nov 25.
Recently, the NHC→B[triple bond, length as m-dash]B←NHC molecule has been published in where it is described as a stabilized B molecule in its Σ excited state (B*) (NHC = N-heterocyclic carbene CNH(CHPr -2,6)). The bonding of based on sophisticated calculations and the BB distances of the solid compound was discussed as the first example of a B triple bond in a stable molecule. Now we present an only experimentally based interpretation of detailed thermodynamic considerations, including its fragmentation to B molecules. Furthermore, from the vibrational spectrum force constants ( for the BB bond and for the BC bond) were extracted, which are classical examples to indicate single, double and triple CC bonds in organic chemistry. The consequence of both properties of (Δ and ) generates a new interpretation which is in contrast to the triple bond donor-acceptor description visualized by arrows and which casts a critical light on the interpretation of any NHC "stabilized" molecule.
最近，NHC→B≡B←NHC分子已被发表，文中将其描述为处于Σ激发态（B*）的稳定硼分子（NHC = N-杂环卡宾CNH(CHPr -2,6)）。基于精密计算对其键合以及固体化合物中B-B键长进行了讨论，该化合物被视为稳定分子中硼三键的首个实例。现在我们给出一种仅基于实验的解释，并进行详细的热力学考量，包括其分解为硼分子的过程。此外，从振动光谱中提取了力常数（B-B键的 和B-C键的 ），这是有机化学中指示单键、双键和三键的典型例子。 的这两种性质（Δ和 ）的结果产生了一种新的解释，这与用箭头表示的三键供体-受体描述相反，并且对任何NHC“稳定”分子的解释提出了批判性的观点。
