An ESIPT based turn on fluorochromogenic sensor for low level discrimination of chemically analogous Zn~(2+) and Cd~(2+) & aqueous phase recognition of bio-hazardous CN~(-): From solution state analysis to prototype fabrication

摘要

A versatile naphthalene-benzothiazole-based chemoreceptor (BTN) towards selective recognition of Zn~(2+) and Cd~(2+) is reported in this work. BTN exhibits chromogenic changes (colorless to pale yellow) in presence of Zn~(2+) in purely aqueous medium. It recognizes Cd~(2+) by fluorogenic response (non-fluorescent to blooming green emission). While for bio-hazardous CN~-, it undergoes dual-channel chromo-fluorogenic response. ESIPT-PET-CHEF-ICT-C = N isomerization pathway unveils the underlying host-guest sensing mechanism. The reversiblespectro-scopic response of BTN towards CN~-/H~+ has been functionally aligned with the logic gate mimic ensemble. Theoretical studies by DFT and electrostatic potential surface analyses further strengthen the recognition phenomenon. BTN undergoes endogenous CN~- detection in natural sources like bitter almonds. FE-SEM analysis of BTN displayed varying morphological responses in the presence of Zn~(2+) and Cd~(2+). In vitro Cd~(2+) and CN~-detection in Tecoma Stans and Yeast cells confirms its cell permeability and biocompatibility. Interestingly, RGB-based easy-instant-economic prototype is fabricated that escalates the practical application of BTN towards on-field CN~- detection. This work indeed opens up a facile and promising route for fabricating selective and sensitive sensing platforms, with good performance towards multi analytes recognition by varying photophysical signaling.