Metal-free binding and coupling of carbon monoxide at a boron–boron triple bond

• Published in: Nature chemistry Vol. 5; no. 12; pp. 1025 - 1028
• Main Authors: Braunschweig, Holger, Dellermann, Theresa, Dewhurst, Rian D., Ewing, William C., Hammond, Kai, Jimenez-Halla, J. Oscar C., Kramer, Thomas, Krummenacher, Ivo, Mies, Jan, Phukan, Ashwini K., Vargas, Alfredo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2013; Nature Publishing Group
• Subjects: 639/638/263/406; Analytical Chemistry; Atmospheric pressure; Biochemistry; Boron; Boron - chemistry; Carbon monoxide; Carbon Monoxide - chemistry; Chemical bonds; Chemistry; Chemistry/Food Science; Crystallography, X-Ray; Electrochemical Techniques; Electrochemistry; Inorganic Chemistry; Magnetic Resonance Spectroscopy; Metals; Models, Molecular; Organic Chemistry; Physical Chemistry; Synthesis gas
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/nchem.1778

Many metal-containing compounds, and some metal-free compounds, will bind carbon monoxide. However, only a handful of metal-containing compounds have been shown to induce the coupling of two or more CO molecules, potentially a method for the use of CO as a one-carbon-atom building block for the synthesis of organic molecules. In this work, CO was added to a boron–boron triple bond at room temperature and atmospheric pressure, resulting in a compound into which four equivalents of CO are incorporated: a flat, bicyclic, bis(boralactone). By the controlled addition of one CO to the diboryne compound, an intermediate in the CO coupling reaction was isolated and structurally characterized. Electrochemical measurements confirm the strongly reducing nature of the diboryne compound. The coupling of carbon monoxide molecules is an attractive prospect for organic synthesis, but only a few metal complexes are known to do this. A compound containing a boron–boron triple bond has now been shown to induce the coupling of four CO molecules, through an intermediate with a single CO.