Anion-driven conformation control and enhanced sulfate binding utilising aryl linked salicylaldoxime dicopper helicates.

The synthesis and spectroscopic analysis of both "metal-only" and anion encapsulated dicopper(II) double helicates utilising a new 1,4-aryl spacer is described. X-Ray crystallographic analysis of the complexes reveal that the aromatic spacer increases rigidity in the complex, yet the complexes are still able to undergo a dramatic "coiling up" to bind anions. Spectroscopic analysis has shown a clear enhancement in the binding strength of SO(4)(2-) over the non-coordinating anions ClO(4)(-), NO(3)(-) and Br(-) which has been attributed to a combination of enhanced rigidity in the complex and an increased electrostatic interaction between the complex and the dianion.