CRYSTAL-STRUCTURE OF THE 1 1-MOLECULAR-COMPLEX BETWEEN WATER AND 6-DIAZA-4,7,10,13-TETRAOXACYCLOEICOSA-17,20-DIONE/

The twenty-membered macrocycle, 18,19-benz-1,16-diaza-4,7, 10,13-tetra oxacycloeicosa-17,20-dione (1) and water form a stoichiometric 1:1 inc lusion compound. The crystal structure of [1.H2O] has been determined by X-ray crystallography. Crystals of [1.H2O] are orthorhombic, space group Pca2(1), a = 8.654(2), b = 10.947(2), c = 21.486(4) Angstrom and Z = 4. The final R-value is 0.046 for 1795 reflections with I > 2 sig ma (I). The structure reveals host-guest hydrogen bonding with the mix ed set of ligand sites (O,N). Between the molecular complexes there ar e NH ... O = C contacts joining these entities in chains along the x a xis. Besides these, intramolecular C = O ... C = O dipole-dipole inter actions have been found in (1).