Novel B–H hydrogen bond observed

Abstract

A weak type of hydrogen bond is known to form between C–H, N–H, and O–H groups and the π electron cloud of an aromatic ring. Similar interactions have been predicted for B–H groups on compounds such as diborane (B2H6) and o-carborane (C2B10H12), in which the electronic structure produces a slight positive charge on the B–H hydrogens. A complex with a B–H···π interaction has now been created and characterized by a team led by Hong Yan of Nanjing University and Dieter Cremer of Southern Methodist University (J. Am. Chem. Soc. 2016, DOI: 10.1021/jacs.6b01249). The ability to promote such interactions could have applications in molecular assembly and pharmaceutical binding. The researchers treated an iridium-dithiolene-carborane complex with phosphines to produce a molecule in which a carborane B–H group is in position to form a hydrogen bond with one of the phosphine phenyl rings. The researchers confirmed the hydrogen bond experimentally using NMR and