Design of large Stokes shift fluorescent ortho-bis-styrylbenzenes. Optical characterization and fluoride sensing in logical gates

This study combines underexplored fluorescent structures with large Stokes shifts, such as ortho-derivatives of bis(styryl)benzenes, for detecting three anions (fluoride, cyanide, and hydroxyl) through the implementation of fluorescent molecular logic gates. Importantly, this approach allows for the detection of multiple analytes and discrimination between analytes with closely similar behaviours, reducing the need for sample pre -treatments and enhancing efficiency in complex environmental analyses. Compounds with large Stokes shifts are essential in spectroscopy, offering reduced self-absorption, improved sensitivity, minimal spectral overlap, better resolution, and interference -free use of multiple fluorescent compounds. Therefore, we present a study on how the substitution of these oBSB compounds influences their optical properties. Through Time -Dependent Density Functional Theory (TD-DFT) calculations, we gain comprehensive insights into the molecular structure and photophysical properties, elucidating the exceptional Stokes shift exhibited by these compounds. Additionally, our findings offer a deeper understanding of the electronic states and changes in molecular geometry that contribute to their unique optical behaviour. Finally, the appropriate analysis of the fluorescent responses of these compounds as inputs in logic gates allows the detection of fluoride, cyanide, or hydroxyl anions in an unknown sample.