Structure of a Self‐Assembled Chain of Water Molecules in a Crystal Host

The role of hydrogen bonding in water is important in determining the structure, stability, and function of biological assemblies. The supramolecular structure of 1,4,7,10-tetraazacyclododecane, a molecule that has secondary NH bonds similar to those found in biological systems, contains an infinite chain of tetrameric water clusters (depicted, oxygen: red; hydrogen: white). This motif, until now, has not even been speculated upon.