Preparation of a polymer-supported fluorene-based receptor for quantitative and efficient binding of silver cations.

We have designed and synthesized a polymer-supported material in which a versatile fluorene-p-xylene-based receptor is woven onto the backbone of polystyrene. This polymer-supported receptor adopts a pi-prismand-like conformation through a simple C--C bond rotation that results in the quantitative binding of a single silver cation per receptor site with a remarkable efficiency that exceeds the binding abilities of the well-known tris[2.2.2]-p-cyclophane (or pi prismand) by at least a factor of 100. More importantly, the binding event can be readily monitored by 1H NMR spectroscopy, as well as by a more sensitive emission spectroscopic technique in which the quenching of fluorescence of the receptor moiety is quantitatively related to the binding of silver cations.