Fine tuning of receptor polarity for the development of selective naked eye anion receptor

We designed and synthesized new anion receptors 1, 2, and 3, which have different N–H polarity. According to their N–H polarities, these receptors showed different selectivities for the anions they were interacting with. The difference of selectivity could be easily recognized from their color change during recognition events. Therefore, fine tuning of receptor polarity could be a good strategy for the designing of a selective anion receptor and made it possible to develop a selective naked eye anion receptor.