Selective binding of (thio)sulfate and phosphate in water by quaternary ammonium functionalized oligo-ureas.

Recognition of (thio)sulfate and phosphate in aqueous solutions has been demonstrated by using oligo-urea-based receptors functionalized with quaternary ammonium groups. The ammonium groups allow for increased aqueous solubility while simultaneously providing positive coulombic interactions and stronger hydrogen bonding through an inductive effect. This simple and generally applicable modification provides an effective way to bolster the anion binding and water solubility of oligo-urea-based receptors. With a water soluble receptor 2, selective binding of adenosine phosphates was achieved at physiological pH.