Carbonate and oxalate dianions as prolific hydrogen-bond acceptors in supramolecular assemblyElectronic supplementary information (ESI) available: synthesis details for 1 and 2; Figs. 5 and 6. See http://www.rsc.org/suppdata/cc/b3/b306649e/Dedicated to Prof. James Trotter on the occasion of his 70th birthday.

In the new inclusion compound [(C2H5)4N+]2 x CO3(2-) x 7(NH2)2CS, the carbonate ion is surrounded by twelve convergent NH donor groups from six thiourea molecules to form a hydrogen-bonded aggregate shaped like two concave three-leaved propellers sharing a common core, whereas in [(n-C3H7)4N+]2 x C2O4(2-) x 4(NH2)2CS the oxalate ion serves as a hub for binding four thiourea molecules to generate a cross-shaped structural motif.