Dihydrogen bond

Interest in dihydrogen bonding was reignited upon the crystallographic characterization of the molecule H3NBH3.

In this molecule, like the one studied by Brown and Hazeltine, the hydrogen atoms on nitrogen have a partial positive charge, denoted Hδ+, and the hydrogen atoms on boron have a partial negative charge, often denoted Hδ−.

In contrast, the related substance ethane, H3CCH3, is a gas with a boiling point 285 °C lower.

[1] Protonation of transition metal hydride complexes is generally thought to occur via dihydrogen bonding.

[5] So-called hydrogen–hydrogen bond interactions have been proposed to occur between two neutral non-bonding hydrogen atoms from atoms in molecules theory, while similar interactions have been shown to exist experimentally.

Dihydrogen bonding is evident in the close H---H contacts between water of crystallization and the borohydride anion in the salt NaBH 4 (H 2 O) 2 . [ 1 ]
Dihydrogen bonding exists between the hydroxypyridine and a hydride ligand in this iridium complex.