LAUSR

Abstract A tetracarboxamide-based macrocycle has shown a general aptitude for binding both anions and metal cations. Crystallographic studies indicate that in several instances quite similar structures are obtained. The macrocycle can be readily synthesised by a one-step condensation. Smaller oxoanions (sulfate, oxalate, and nitrite) bind within a folded macrocyclic cleft. Larger oxoanions and oxometallates (dihydrogen phosphate, dichromate, and perrhenate) dangle below the folded macrocycle. Smaller divalent metal ions (nickel(II) and copper(II)) form binuclear complexes with the metal ions bound within the folded macrocycle. The larger palladium(II) also forms a ditopic complex with the two pincers units, but the macrocycle lies in a more planar, non-folded conformation.