Anion Coordination into Ligand Clefts

A tripodal anion receptor has been obtained by an easy and fast single-reaction synthesis from commercial reagents. The three ligand arms-bearing aromatic groups able to form anion-pi interactions define ligand clefts where large anions, such as perchlorate and perrhenate, are included. We report here the synthesis of the ligand, its acid/base properties in an aqueous solution which has been used to direct the synthesis of anion complexes, and the crystal structure of the free ligand and its anion complexes H3L(ClO4)(2)(H2O)-H-center dot and H3L(ReO4)(2).