From calixfurans to heterocyclophanes containing isopyrazole units

Cyclic poly-1,4-diketones , obtained by the oxidation of the furan units present in calix[4]furan and calix[6]furan have been converted into the novel heterocyclophanes and containing four and six isopyrazole units, respectively. Solution studies have demonstrated the ability of and to act as ligands for transition metals. The crystal structures of and the coordination compound formed by with 2 equiv. of cis-PtCl2(DMSO)2 have been determined. In the solid state is shown to bind aromatic substrates within its cavity.