Macrocyclic sulfamides: synthesis, hybridization, and metal binding properties

Four cyclophanes incorporating the cyclosulfamide sub-unit have been synthesised in high yield. The X-ray crystal structures of three of them, and of cyclosulfamide itself, provide useful insight into the hybridisation of such compounds. The ionophoric properties of the macrocycles are also reported, with the sulfamides showing unusual selectivity for rubidium (benzyl trimer), barium (pyridyl dimer) and silver (pyridyl dimer and trimer).