Crystal structure of the 1:1 molecular complex between water and 18,19-benz-1,16-diaza-4,7,10,13-tetraoxacycloeicosa-17,20-dione

Abstract

The twenty-membered macrocycle, 18,19-benz-1,16-diaza-4,7, 10,13-tetraoxacycloeicosa-17,20-dione (1) and water form a stoichiometric 1:1 inclusion compound. The crystal structure of [1.H₂O] has been determined by X-ray crystallography. Crystals of [1.H₂O] are orthorhombic, space group Pca2₁, a = 8.654(2), b = 10.947(2), c = 21.486(4) Å and Z = 4. The final R-value is 0.046 for 1795 reflections with I > 2σ (I). The structure reveals host-guest hydrogen bonding with the mixed set of ligand sites (O,N). Between the molecular complexes there are NH … O = C contacts joining these entities in chains along the x axis. Besides these, intramolecular C = O … C = O dipole-dipole interactions have been found in (1).