Purify the ionophore by flash chromatography (2g of reagent with 30g of Silica Gel 60) and elute with EtOAc/hexane (1:19). The fractions that absorb light at 260nm are pooled, evaporated and dried at room temperature (10.3 Torr). The oily residue is distilled in a bubble-tube apparatus (170o/0.02 Torr). Its IR (CHCl3) has peaks at 1720, 1280, 940cm-1, and its solubility in tetrahydrofuran is 50mg/0.5mL. It is a lipophilic neutral ionophore selective for carbonate as well as being an optical humidity sensor. [Behringer et al. Anal Chim Acta 233 41 1990.]
