Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim/Ruhr, Germany.
Nat Chem. 2009 Jul;1(4):295-301. doi: 10.1038/nchem.248. Epub 2009 Jun 14.
Electron-rich allenes and heterocumulenes are commonly described by the regular notations of organic chemistry. Following on from published results and recent computational studies, we present here a host of crystallographic and reactivity data, as well as theoretical results, that indicate a highly non-canonical bonding situation in many members of this series. These must actually be interpreted as coordination compounds, in which carbon serves as a 'central atom' that interacts with its 'ligand sphere' via donor-acceptor bonds, even if these internal ligands themselves are carbon based. This captodative description is not limited to compounds that supposedly comprise a carbon(0) centre, a peculiar oxidation state that can be probed experimentally by geminal diauration. As the available data suggest that this unconventional interpretation of C-C and C-X bonds is more generally applicable than previously anticipated, it may well affect our understanding of organic chemistry in general.
富电子的丙二烯和杂累积烯通常用有机化学的规则符号来描述。根据已发表的结果和最近的计算研究，我们在这里提供了大量的晶体学和反应性数据以及理论结果，这些数据和结果表明，该系列的许多成员中存在高度非典型的键合情况。这些实际上必须被解释为配位化合物，其中碳作为“中心原子”通过供体-受体键与它的“配体球”相互作用，即使这些内部配体本身也是基于碳的。这种捕获描述不仅限于那些据称包含碳(0)中心的化合物，这种特殊的氧化态可以通过偕二卤化来实验探测。由于现有数据表明，这种对 C-C 和 C-X 键的非常规解释比以前预期的更为普遍适用，因此它很可能会影响我们对一般有机化学的理解。
