New water soluble Hg²⁺ selective fluorescent calix[4]arenes: Synthesis and application in living cells imaging

The present study demonstrates the synthesis of water-soluble fluorescent calix[4]arenes (6 and 7) and its application in living cell imaging for Hg²⁺ detection at a low level. The synthesized fluorescent ligands 6 and 7 were characterized by ¹H NMR technique. The fluorescent study showed both water soluble ligands were Hg²⁺ selective and follow photo-induced electron transfer (PET) process. From the fluorimeter titration experiment detection limit was calculated as 1.14×10^-5 and 3.42×10^-5 for ligand 6 and 7, respectively. From the Benesi-Hildebrand plot binding constant values were evaluated as 666.7 and 733.3M^-1 for 6 and 7, respectively. The interactions between ligands 6 and 7 and Hg²⁺ were also demonstrated in living cells, SW-620, using Fluorescent Cell Imager. While ligands 6 and 7 alone show fluorescent properties, they loss their action with the presence of Hg²⁺ in SW-620 cells.