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 α,ω-diureidoalkanes H2N(CO)NH-(CH2)n-NH(CO)NH2 with n=4 a

We determined the crystal structures of the title compounds H2N(CO)NH-(CH2)n-NH(CO)NH2 with n=4 and 5 to check an idea that the replacement of the terminal methyl group of alkylurea H2N(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 from simple and non-rigid molecules via hydrogen bonds. The crystal structures of the two compounds were found to be quite similar to each other and the basic structure motif of each crystal was an infinite, two-dimensional network of the molecules connected via urea-chains formed by two NH⋯O hydrogen bonds (H-bonds) with graph-set C21(4)[R21(6)]. This network (single-network) comprised (2n+18)-membered open rectangular framework with graph-set R44(2n+18) composed of two molecules as a whole and two ureido groups. Two adjacent single-networks crossed each other to form a 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(8) to give infinite, three-dimensional supramolecular assembly.