Anion recognition properties of receptor based on 2-linked trisindolymethene

A compound based on 2-linked tisindolymethene is studied as a new anion receptor. This receptor selectively F-, AcO- and H2PO4- recognizes by visible color changes. It binds with F-, AcO- and H2PO4- by double hydrogen bonding interactions, and favorable color changes of violet-to-colorless are observed clearly. The addition of excessive F- induces further deprotonation of the receptor, exhibiting the color change from violet to yellow. Due to the positive charge in the molecular structure of the receptor, it can even binding with F- and AcO- in water-containing solution by color change.