Cubane-Like Bismuth-Iron Cluster: Synthesis, X-ray Crystal Structure and Theoretical Characterization of the [Bi4Fe8(CO)28]4– Anion
✍ Scribed by Kirill Yu. Monakhov; Thomas Zessin; Gerald Linti
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 648 KB
- Volume
- 2010
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Abstract
The reaction of cyclo‐Bi~4~[Si(SiMe~3~)~3~]~4~ (1) with Na~2~[Fe(CO)~4~] in the presence of __n__Bu~4~NCl leads to the formation of the cage compound [__n__Bu~4~N]~4~[Bi~4~Fe~8~(CO)~28~] (2). According to X‐ray single‐crystal structure analysis, the faces of the tetrahedral Bi~4~ core are capped by Fe(CO)~3~ moieties in a μ~3~ fashion to give a cubanoid Bi~4~Fe~4~ framework. The four Fe(CO)~4~ fragments are μ~1~‐coordinated to bismuth, each. With 12 skeletal electron pairs the [Bi~4~Fe~8~(CO)~28~]^4–^ anion (2a) is a Bi~4~Fe~4~ cubane. The negative charge is localized within cluster 2a according to the NBO analysis of its derivatives. The strength of metal–ligand interactions Bi–μ~3~‐Fe(CO)~3~ is responsible for the size of the cluster's cubic core. NICS computations at the cage centers of considered molecules show that 2a has paratropic character, whereas removal of four μ~1~‐Fe(CO)~4~ fragments from latter causes spherical aromaticity of the modified clusters [Bi~4~Fe~4~(CO)~12~]^4–^ (2aa) and [Bi~4~Fe~4~(CO)~12~]^2+^ (2ab), mediated by a Bi~4~ cluster π orbital.