Quadruple bonding between iron and boron in the BFe(CO)<sub>3</sub><sup>-</sup> complex.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31624260.
- Also identified by DOI 10.1038/s41467-019-12767-5 and PMC identifier 6797760.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
While main group elements have four valence orbitals accessible for bonding, quadruple bonding to main group elements is extremely rare. Here we report that main group element boron is able to form quadruple bonding interactions with iron in the BFe(CO)<sub>3</sub><sup>-</sup> anion complex, which has been revealed by quantum chemical investigation and identified by mass-selected infrared photodissociation spectroscopy in the gas phase. The complex is characterized to have a B-Fe(CO)<sub>3</sub><sup>-</sup> structure of C<sub>3v</sub> symmetry and features a B-Fe bond distance that is much shorter than that expected for a triple bond. Various chemical bonding analyses indicate that the complex involves unprecedented B≣Fe quadruple bonding interactions. Besides the common one electron-sharing σ bond and two Fe→B dative π bonds, there is an additional weak B→Fe dative σ bonding interaction. This finding of the new quadruple bonding indicates that there might exist a wide range of boron-metal complexes that contain such high multiplicity of chemical bonds.