Selective Recognition and Sensing of Biologically Important Phosphates Using Triptycene-Based Anion Receptors

The overarching aim of supramolecular chemistry is to design and synthesize receptors exhibiting selectivity and efficiency comparable to that found in nature in biological receptors and enzymes. Despite the recent progress, we are still far from designing a receptor selective for a given molecular guest. Phosphate-derived anions are particularly interesting molecular targets because of their multiple cellular functions, being constituents of DNA and RNA as well as taking part in the cellular energy conversion mechanisms. Here, we present a systematic investigation of the anion binding properties of triptycene-based anion receptors, and study them in the solid-state as well as computationally using density functional theory(DFT). Titrations under fluorescence control indicate that receptor 1 is highly selective towards monophosphates derived from nucleotides such as AMP, deoxy-AMP, CMP and UMP with binding constant determined to be in the range 6637 – 100000 M-1. Contrary, phosphate anions derived from cyclic AMP and ADP were not bound by receptor 1, as indicated by no change in fluorescence spectra.