Three-dimensional supramolecular assembly having infinite two-dimensional interlocking networks built up only from simple and non-rigid organic molecules via hydrogen bonds. Crystal structures of a,u-diureidoalkanes H2N(CO)NH–(CH2)n–NH(CO)NH2 with nZ4 and

We determined the crystal structures of the title compounds H2N(CO)NH–(CH2)n–NH(CO)NH2 with nZ4 and 5 to check an idea that the replacement of the terminal methyl group of alkylureaH2N(CO)NH–(CH2)n–CH3 by a ureido group –HN(CO)NH2 is useful to construct two and three-dimensional supramolecular assemblies with unique interlocking networks only fromsimple and non-rigid molecules via hydrogen bonds. The crystal structures of the two compoundswere found to be quite similar to each other and the basic structuremotif of each crystalwas an infinite, two-dimensional network of the molecules connected via urea-chains formed by two NH/O hydrogen bonds (H-bonds) with graph-set C1 2ð4Þ½R12 ð6Þ . This network (single-network) comprised (2nC18)-membered open rectangular framework with graph-set R44 ð2nC18Þ composed of twomolecules as a whole and two ureido groups. Two adjacent single-networks crossed each other to forma double-network characterized by catenane-type interlocks (i.e. an interpenetrating undulating two-dimensional (6,3) double-network). Neighboring double-networks related by center of symmetry were bridged by dimer-type H-bonds with graph-set R22 ð8Þ to give infinite, three-dimensional supramolecular assembly. q 2005 Elsevier B.V. All rights reserved.