Sulfate templated assembly of neutral receptors in aqueous DMSO - orthogonal versus biplane structuresElectronic supplementary information (ESI) available: Synthesis and characterisation of ligands 1-4, titration protocol and fitting results, X-ray analysis. CCDC 968837 and 968838. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3cc48463g

Simple, easily available diamidocarbazoles 1-4 form robust 2 : 1 complexes with SO 4 2− even in the presence of a large excess of water. An appropriate choice of side arms directs the assembly towards the formation of either an orthogonal or a biplane structure, both in solution and in the solid state. Diamidocarbazoles are extremely potent ligands for sulfate anions and may be engineered to form either orthogonal or parallel 2 : 1 complexes.