Hydrogen Bonds in Boronic Acids and Their Complexes

The structures of arylboronic acids, ArB(OH)2, are reviewed. These structures are different depending on the substituents in the aromatic ring. The main types of such forms are hydrogen-bonded dimers and chains in which the second B-OH group forms a hydrogen bond with donor atom. Diboronic acids form two-dimensional networks. The presence of an electron donor group in ortho position usually leads to the formation of intramolecular hydrogen bond, but in some cases intermolecular interactions are also observed. Heterodimers with anions of carboxylic acids and with amino acids are the stable complexes, in opposite to the complexes with monofunctional Lewis bases.