Lehrstuhl Anorganische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany.
Chem Rec. 2010 Dec;10(6):413-6. doi: 10.1002/tcr.201000028.
The synthesis and isolation of stable bimetallic complexes that contain formally quintuply bonded transition metals is a novel and emerging field of science. Efforts have been undertaken in designing and tuning the ligands to achieve a very short (actually the shortest) metal-metal bond. The motivation for these efforts arose from the expectation that an increasing bond order may go along with a shortening of the bond length. In consequence, formally quintuply bonded bimetallics could have shorter metal-metal distances than quadruply bonded ones. A chromium homo-bimetallic complex with a Cr-Cr bond length of 1.7293(12) Å has been synthesized, and a formal bond order of five was assigned. This compound holds the record for the shortest metal-metal bond in a stable molecule to date. At this stage, there is no evidence that additional shortening is impossible.
合成和分离含有形式五重键过渡金属的稳定双金属配合物是一个新颖且新兴的科学领域。人们一直在努力设计和调整配体，以实现非常短（实际上是最短）的金属-金属键。这些努力的动机源于这样的期望，即键级的增加可能伴随着键长的缩短。因此，形式五重键双金属配合物的金属-金属距离可能比四重键双金属配合物更短。已经合成了具有 1.7293(12)Å Cr-Cr 键长的铬同核双金属配合物，并赋予其五重键的形式键级。该化合物创下了迄今为止稳定分子中最短金属-金属键的记录。在现阶段，没有证据表明进一步缩短是不可能的。
