Oxoborane

In chemistry, an oxoborane is any chemical compound containing a boron atom with a terminal oxygen atom. The compound class is of some relevance to academic research. The parent compound, HBO, itself called "oxoborane", together with derivatives FBO (fluorine), ClBO chlorine, BrBO bromine, HOBO (hydroxyl) and MeBO (methyl) have been detected in matrix isolation or in the gasphase at high temperature.^[1][2] In these compounds the boron and oxygen form a triple bond prone to cyclotrimerization to boroxines.

The first stable oxoborane with a double bond of the type (R₂N)₂B=O was described in 2005.^[3] In this compound the oxygen atom is coordinated to aluminium chloride. The BO bond length is 130 pm (compare to 136 pm in regular boronic acids). Another such system was described in 2011 ^[4]

A stable compound with a BO triple bond is trans-[(PCy₃)2PtBr(BO)] with platinum coordinated to the BO unit.^[5] In this compound the BO bond length is 120 picometers.

References

1. Inorganic chemistry, Egon Wiberg,Nils Wiberg,Arnold Frederick Holleman
2. Westcott, S. A. (2010), BO Chemistry Comes Full Circle. Angewandte Chemie International Edition, 49: 9045–9046. doi:10.1002/anie.201003379
3. Synthesis and Characterization of a Coordinated Oxoborane: Lewis Acid Stabilization of a Boron−Oxygen Double Bond Dragoslav Vidovic, Jennifer A. Moore, Jamie N. Jones, and Alan H. Cowley J. Am. Chem. Soc., 2005, 127 (13), pp 4566–4567 doi:10.1021/ja0507564
4. Wang, Y., Hu, H., Zhang, J. and Cui, C. , Comparison of Anionic and Lewis Acid Stabilized N-Heterocyclic Oxoboranes: Their Facile Synthesis from a Borinic Acid. Angewandte Chemie, n/a. doi: 10.1002/ange.201007417
5. Oxoboryl Complexes: Boron−Oxygen Triple Bonds Stabilized in the Coordination Sphere of Platinum Holger Braunschweig, Krzysztof Radacki and Achim Schneider Science 16 April 2010 Vol. 328 no. 5976 pp. 345-347 doi:10.1126/science.1186028