Unexpected conformational consequences of weak hydrogen bonds on 1,3,7,9,13,15,19,21-octaazapentacyclo[19.3.1.1(3,7).1(9,13).1(15,19)]octacosane monohydrate.

In the title compound, C(20)H(40)N(8).H(2)O, the organic molecule crystallizes with one water molecule located within the molecular cavity of the octaaza macrocycle. The two molecules are linked via two weak O-H...N hydrogen bonds. The assembly has noncrystallographic C(2) axial symmetry.