LAUSR

The host-guest properties of [15]paracyclophane are engendered by π-metalation which exhibits fantastic regioselectivity towards the macrocyclic molecule. The synthesis and characterization of mono-, di- and tri-metalated [15]PCPs are discussed in this article and the anion binding behavior of the 3Ru-[15]PCP-II6+, one of the trimetalated [15]PCPs, driven by anion-π interactions are comprehensively demonstrated in both solution and solid state. The anion binding properties of the 3Ru-[15]PCP-II6+ in solution are investigated by 1H NMR titrations, showing selectivity towards ReO4- both in organic and aqueous solutions. The binding mode is unexpected; the anionic guest stacks over the host rather than threads it. This selectivity for ReO4- is also supported by water-nitromethane extraction experiments which demonstrate that its partition from water into the organic phase by 3Ru-[15]PCP-II6+ is maintained to some extent in the presence of excess Cl-, SO42-, H2PO4-, NO3- and ClO4-.