Hydrogen bonding is a type of weak bond between molecules can occur when a hydrogen atom is bonded to a strongly electronegative atom, and is attracted to a nearby electronegative atom from another molecule. Even though this attraction forms a relatively weak chemical bond, when there are a lot of hydrogen bonds working together, they can have large effects. For example, hydrogen bonding between water molecules gives water an extremely high surface tension, which allows some insects to walk across the surface of a pond without sinking.
In water, hydrogen atoms are bonded to electronegative oxygen atoms and the hydrogen atoms are attracted to oxygen atoms from other water molecules. The hydrogen atoms in water molecules can also be attracted to other electronegative atoms, like negatively charged atoms, or anions.
Hexahydroxyterphenyl is a molecule that has six hydrogen atoms bonded to oxygen atoms. Like the hydrogen atoms in water, these O-H hydrogen atoms in hexahydroxyterphenyl can bind to negatively charged anions. We have used this special type of hydrogen bonding to form large molecules, linking together hexahydroxyterphenyl molecules and anions through hydrogen bonds to form interesting structures.
This work was done by Nick, currently a post-doc in our group, and Veronica, a PhD student who determined the structures. Check out more of their neat structures at http://pubs.acs.org/doi/abs/10.1021/acs.cgd.5b00062.