A near-infrared fluorescent chemodosimeter for silver(I) ion based on an expanded porphyrin

An expanded porphyrin [26]hexaphyrin(1.1.1.1.1.1) was exploited as a fluorescent chemodosimeter for Ag+ ions with high sensitivity and selectivity via near-infrared luminescence above 900 nm, a region that is free from optical interference in the visible wavelength range induced by the commonly used matrix and other organic compounds. The association constant for the Ag+–porphyrin complexation was evaluated by spectroscopic titration method to be 7.24 × 1010 M−1.