Halogen Bonding Ionophore for Potentiometric Iodide Sensing.

Iodide (I-) is an essential micronutrient for thyroid function. Hence, rapid and portable sensing is important for I- quantification in food and biological samples. Herein, we report the first example of a halogen bonding (XB) tripodal ionophore (XB1) which is selective for the I- anion. NMR binding studies of XB1 and its H-triazole analog HB2 with I- demonstrated the dominant influence of XB interactions between the ionophore and the I- analyte. The phase boundary model was applied to formulate iodide-selective electrodes with the ionophore XB1. The optimal electrode exhibited a near-Nernstian response of -51.9 mV per decade within a large dynamic range (10-1 to 10-6 M) and notably anti-Hofmeister selectivity for I- over thiocyanate (SCN-), enabling the in situ determination of I- in complex samples. This work establishes XB as a viable supramolecular interaction in the potentiometric sensing of anions.