Two‐channel near‐infrared fluorescence Ag+ ion sensing of a new star‐shaped dendrimer

A new near‐infrared fluorescence sensor PDI‐PD for Ag⁺ ions was successfully prepared and its structure characterized by ¹H nuclear magnetic resonance (NMR), ¹³C NMR and high‐resolution mass spectrometry; matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (HRMS MALDI‐TOF). The probe exhibited rapid, sensitive, and selective two‐channel fluorescence responses towards Ag⁺ ions and protons. The probe has a marked high binding affinity and high sensitivity for Ag⁺, with a detection limit of 1.4 × 10^?6 M. An approximately five‐fold enhanced core emission at 784 nm was attributed to fluorescence resonance energy transfer (FRET). The enhanced core emission of the probe with Ag⁺ ions based on photo‐induced electron transfer and FRET is discussed. In addition, the probe presented a visible colour change. All experimental results demonstrated that PDI‐PD is an efficient tool for the selective, sensitive and rapid detection of Ag⁺ ions and protons using two‐channel fluorescence responses.