title: Zwitterionic dicopper helicates: anion encapsulation and binding studies.
abstract: The synthesis and spectroscopic studies of a dicopper(II) double helicate capable of binding anions is described. X-Ray crystallographic analysis of three anion variations of the complex have shown that the helicate is capable of accommodating anions with an approximate volume of 0.09 nm(3) and smaller. ESI-MS revealed that the supramolecular complexes retain the 2 : 2 ligand : metal cluster in solution. Spectrometric analysis has shown the complex is capable of binding anions in a 1 : 1 ratio of helicate to anion, in the order SO(4)(2-) > HPO(4)(2-) > ClO(4)(-) approximately BF(4)(-) approximately NO(3)(-). We demonstrate that coordination to the metal centre, H-bonding and electrostatic interactions all play a role in encapsulating the anions.
authors.affiliation: Institute of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
authors.forename: Marco
authors.initials: M
authors.lastname: Wenzel
authors.forename: Sam R
authors.initials: SR
authors.lastname: Bruere
authors.forename: Quintin W
authors.initials: QW
authors.lastname: Knapp
authors.forename: Peter A
authors.initials: PA
authors.lastname: Tasker
authors.forename: Paul G
authors.initials: PG
authors.lastname: Plieger