Tandem Detection of Sub-Nano Molar Level CN(–) and Hg(2+) in Aqueous Medium by a Suitable Molecular Sensor: A Viable Solution for Detection of CN(–) and Development of the RGB-Based Sensory Device

[Image: see text] 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 × 10(4) 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 Hg(2+) 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.