Structure of host-guest assemblies involving interaction of cyclen with diphenylphosphinic and 4-tert-butylbenzoic acid

The synthesis and characterisation by single crystal X-ray diffraction of 1:2 host-guest assemblies formed between the tetra-amine macrocycle 1,4,7,10-tetraazacyclododecane (cyclen) and diphenylphosphinic acid or 4-tert-butylbenzoic acid are reported. In each case strong hydrogen bonds associated with proton transfer from the acid species to two (trans) amino groups in the cyclen ring are observed. Both adducts are also associated with complex hydrogen bonded networks involving the secondary amines and water molecules, with each crystal structure containing five water molecules per asymmetric unit.