Simultaneous Sensing of Aqueous Anions and Toxic Metal Ions by Simple Dithiosemicarbazones and Bioimaging of Living Cells

New thiophene ( TSC-1 ) and bipyridine ( TSC-2 ) anchored thiosemicarbazones were synthesized for the recognition of biologically active and toxic analyte. Both the receptors TSC-1 and TSC-2 commonly exhibited strong sensitivity toward anions such as F –, AcO –, and CN – ions over other anions, whereas TSC-1 and TSC-2 recognized Cd 2+ and Hg 2+ ions, respectively. Both anion and cation recognition were clearly differentiated from colorimetric, absorption, and emission responses. A significant shift with remarkable fluorescence enhancement at 540 nm was observed for TSC-1 -Cd 2+, which describes an internal charge transfer (ICT) mechanism. In contrast, anion complexes of TSC-1 show fluorescence enhancement at 570 nm. TSC-2 acts as a photoinduced electron transfer (PET) sensor during both anion and cation sensing accompanied by fluorescence quenching. Furthermore, TSC-1/2 preferentially recognizes cations in the presence of competitive anions. Interestingly, selective detection of the CN – ion using the Hg 2+ - TSC-2 ensemble also achieved through a relay recognition method. Job’s plot analysis reveals that TSC-1/2 binds with the selective anions in 2:1 mode, and 1:1 mode was determined for Cd 2+ - TSC-1 and Hg 2+ - TSC-2, respectively. TSC-1 can be utilized for practical applications such as the recognition of targeted F – ions in daily used household toothpaste, and Cd 2+ ion detection was achieved in living cells using bioimaging.