Host-guest interactions of coumarin-based 1,2-pyrazole using analytical and computational methods: Paper strip-based detection, live cell imaging, logic gates and keypad lock applications

A novel Coumarin-based 1,2-pyrazole, HCPyTSC is synthesised and characterized. The chemosensor has been shown to have efficient colourimetric and fluorescence sensing capabilities for the quick and selective detection of fluoride and copper ions. At 376 and 430 nm, the HCPyTSC exhibits selective sensing for Cu²⁺ and F⁻ ions. By examining the natural bond orbital (NBO) analysis and the potential energy curve (PES) of the ground state for the function of the C–H bond, it has been determined from the theoretical study at hand that the deprotonation was taken from the ‘CH’ proton of the pyrazole ring. For F⁻ and Cu²⁺, the HCPyTSC detection limits were 4.62 nM and 15.36 nM, respectively. Similarly, the binding constants (Kb) for F⁻ and Cu²⁺ ions in acetonitrile medium were found to be 2.06 × 10⁵ M⁻¹ and 1.88 × 10⁵ M⁻¹. Chemosensor HCPyTSC with and without F⁻ and Cu²⁺ ions have an emission and absorption response that can imitate a variety of logic gates, including the AND, XOR, and OR gates. Additionally, a paper-based sensor strip with the HCPyTSC was created for use in practical, flexible F⁻ sensing applications. The paper-based sensor was more effective in detecting F⁻ than other anions. The effectiveness of HCPyTSC for the selective detection of F⁻ in living cells as well as its cell permeability were examined using live-cell imaging in T24 cells.