Tandem Detection of Sub-Nano Molar Level CN– and Hg2+ in Aqueous Medium by a Suitable Molecular Sensor: A Viable Solution for Detection of CN– and Development of the RGB-Based Sensory Device

An inimitable urea-based multichannel chemosensor, DTPH [1,5-bis-(2,6-dichloro-4-(trifluoromethyl)­phenyl)­carbonohydrazide], was examined to be highly proficient to recognize CN– based on the H-bonding interaction between sensor −NH moiety and CN– in aqueous medium with explicit selectivity. In the absorption spectral titration of DTPH, a new peak at higher wavelength was emerged in titrimetric analytical studies of CN– with the zero-order reaction kinetics affirming the substantial sensor–analyte interaction. The isothermal titration calorimetry (ITC) experiment further affirmed that the sensing process was highly spontaneous with the Gibbs free energy of −26 × 104 cal/mol. The binding approach between DTPH and CN– was also validated by more than a few experimental studies by means of several spectroscopic tools along with the theoretical calculations. A very low detection limit of the chemosensor toward CN– (0.15 ppm) further instigated to design an RGB-based sensory device based on the colorimetric upshots of the chemosensor in order to develop a distinct perception regarding the presence of innocuous or precarious level of the CN– in a contaminated solution. Moreover, the reversibility of the sensor in the presence of CN– and Hg2+ originated a logic gate mimic ensemble. Additionally, the real-field along with the in vitro CN– detection efficiency of the photostable DTPH was also accomplished by using various biological specimens.