INHIBIT Logic Research Articles

Rhodamine based turn-on dual mode chemosensor for the selective recognition of nickel ions: practical and theoretical applications.

This work presents the development of a rhodamine-based colorimetric and turn-on fluorescent chemosensor (P1) designed for selective recognition of Ni2+ ions. Chemosensor P1 exhibited remarkable sensitivity and selectivity for Ni2+ ions, exhibiting clear colorimetric and fluorescence responses. The binding interactions were meticulously examined using UV-Vis. and fluorescence spectroscopy, demonstrating a 1 : 1 stoichiometric ratio between P1 and Ni2+ ions via a Job's plot and Benesi-Hildebrand analysis, while the binding constant and limit of detection were established as 0.8919 × 104 M-1, and 2.15 nM, respectively. Interference studies demonstrated that competing metal ions had a minimal effect on the selectivity of the sensor. Chemosensor P1 showed practical applicability by fabricating paper strips and solid-state silica gel systems, facilitating the rapid and visible detection of Ni2+ ions. Their stability and effectiveness were confirmed under a wide range of pH conditions. A molecular INHIBIT logic gate was created utilizing Ni2+ and EDTA as inputs in conjunction with memory devices featuring a "write-read-erase-read" binary logic function, highlighting P1's capabilities in logic-based sensing and data storage. Furthermore, P1 demonstrated reversible binding to Ni2+ in the presence of EDTA, enhancing its versatility. Density Functional Theory (DFT) calculations offered valuable insights into the molecular interactions, while the analysis of actual juice samples confirmed the efficacy of P1 for detecting Ni2+ in complex matrices, making it an exceptional candidate for advanced environmental and analytical sensing technologies with outstanding selectivity and versatility.

A Click-generated chalcone allied triazole sensor for Co (II) with INHIBIT logic gate construction and its antioxidant properties

This article presents the synthesis of chalcone allied 1,2,3-triazole via an aldol-click reaction. The newly synthesized compound chalcogenyl based 1,2,3-triazole (7) selectively detects Co (II) ion over other metal cations by UV–visible photophysical study with the limit of detection value of 1.24 × 10-8 M. Job’s plot confirms that compound (7) and the Co (II) metal ion have 1:1 binding stoichiometry. The binding mechanism between Co (II) and sensor was confirmed by using 1H NMR spectroscopy, mass spectrometry and DFT studies. The reversible behaviour of 7 towards Co (II) was used to construct a molecular logic gate. The compound (7) demonstrated good antioxidant activity with an IC50 value of 3.04 µM in comparison to 1.31 µM of DPPḢ. Further, to explore the antioxidant effect of ligand 7, the molecular docking analysis was performed with xanthine oxidase protein and the obtained binding energy was −11.08 kcal/mol.

An azine‐based halochromic molecular chameleon

Halochromism has a plethora of uses in the textile industry, including wound treatments and protective apparel. Reactive dye’s fastness and a wide variety of hues, from bright to dull, make it ideal for coloring cotton and other regenerated cellulose fibers. It is also fundamentally paramount importance to determine the freshness of packaging foods. In this study, a halochromic probe, 4,4′-((1E,1′E,3E,3′E)-hydrazine-1,2-diylidenebis(prop-1-en-1-yl-3-ylidene))bis(N, N-dimethylaniline), HDBD, has been introduced utilizing a simple condensation reaction. Through the protonation and deprotonation process with the addition of acid and base in the non-aqueous medium, HDBD shows visual colorimetric as well as ratiometric UV–visible absorption spectral change. A colorimetric paper strip-based experiment has been demonstrated to detect trace amounts of acid and its reversibility with bases in non-aqueous solvents. Further, a dip-stick experiment was also carried out for the detection of acid-base vapor in a wide range of concentrations. Furthermore, the overlapping indicator method is explored to estimate acid dissociation constants in the non-aqueous medium. Moreover, we have constructed the INHIBIT (INH) and IMPLICATION (IMP) molecular logic gates exploring the reversibility of HDBD due to the cascade introduction of acid-base as chemical encoded inputs. Utilizing a reversible and reproducible detecting method, we have constructed a molecular-scale additional memory device that demonstrates binary logic “Writing-Reading-Erasing-Reading” and “Multi-write” functions. This finding provides a new way for designing acid-base indicators, which could estimate the acid dissociation constants of various acids in the non-aqueous environment which is fundamentally important in the field of acid-catalyzed organic synthesis.

Designing Unconventional Molecular Ternary INHIBIT Logic Gate and Crafting Multifunctional Molecular Logic Systems.

The paper describes an improved method for building flexible interswitchable logic gates such as rare-type molecular ternary INHIBIT and combinational logic circuits using a specially designed pyridine-end oligo-p-phenylenevinylene compound featuring alkyl substituents (-C16H33) in a THF medium. The probe molecule showed distinct opto-chemical signals upon interaction with Cu(II) and Hg(II) in THF medium. It is interesting to note that the presence of certain anions (S2-, I-, and CN-) could specifically mask the interaction of either of these metal ions or both. The most exciting thing is that we used a completely new gate design technique to construct a rare-type ternary INHIBIT logic gate using Cu(II), Hg(II), and CN- ions as three chemical inputs. With the identical set of chemical inputs, two more ternary combinational logic circuits were created out of these case-specific, independent reversible and irreversible spectroscopic studies. Finally, we were able to design adaptive molecular logic systems composed of several logic gates, including NOR, AND, IMPLICATION, INHIBIT, TRANSFER, and COMPLEMENT, that in this specific situation change the sort of logic sense by effortless optical toggling.

Fabrication of molecular-scale logic devices and implication of artificial neural networks for analysis of anion-responsive behaviors of luminescent ruthenium-terpyridine complex

Anion responsive spectral characteristics of a homoleptic luminescent Ru(II)-terpyridine complex derived from 4′-(p-triphenylphosphoniummethylphenyl)-2,2′:6′,2″-terpyridine bromide (tpy-PhCH2PPh3Br) ligand has been utilized here to mimic the operation of several advanced logic functions. The complex displays remarkable change in absorption and emission spectral profiles in presence of selected anions due to concerted hydrogen bonding followed by anion-induced proton abstraction. Importantly, deprotonation by specific anions followed by restoration to the initial form of the complex is feasible in presence of acid and the process could be recycled. The spectral responsiveness of the complex is employed to mimic various advanced Boolean logic functions, such as IMPLICATION, INHIBIT and combinational logic gates. Execution of exhaustive sensing investigations is often labor-intensive and time-consuming. To address the gap, we employed herein artificial neural network (ANN) models employing three different training algorithms, viz. Bayesian Regularization (BR), Scaled Conjugate Gradient (SCG), and Levenberg-Marquardt (LM) for comprehensive analysis and prediction of the experimental observations. We also compared the outcomes of these models with one another as well as with the experimental data to enable an accurate modeling of the complex’s anion-sensing behavior.

A bicarboxaminoquinoline-based ratiometric fluorescent sensor for the sequential detection of Zn2+ and PPi

A new ratiometric fluorescent sensor (LP) based on bicarboxaminoquinoline was designed and synthesized for sequentially recognizing Zn2+ and PPi. In aqueous solution, LP exhibited the ratiometric fluorescence response towards Zn2+, along with the about 4-folds enhancement of fluorescence quantum yield. Subsequently, the LP-Zn2+ complex displayed the fluorescence recovery upon adding PPi through the displacement strategy. And the LODs of LP and its Zn2+ complex for sensing Zn2+ and PPi were found to be 15 nM and 5.5 nM, respectively. Notably, the reversibility of LP for sequentially sensing Zn2+ and PPi had been employed to construct the INHIBIT logic gate. Moreover, LP and its Zn2+ complex had been successfully utilized for the detection of Zn2+ and PPi in two real water samples and cells imaging.

Detection of copper in tea and water sample: A click-oriented azomethine-based 1,2,3-triazole fluorescent chemosensor with reversible INHIBIT logic gate behavior and computational aspects

A fluorescent azomethine-scaffolded-1,2,3-triazole linked chemosensor was synthesized utilizing alkyne and azidomethylbenzene via Cu(I)-catalyzed click chemistry. The compounds (3–5 and L6) were analyzed using FTIR, 1H NMR, 13C NMR, and GCMS–. The exploration of ion sensing ability of L6 complex, using UV–Vis and fluorescence spectroscopy in ACN:H2O (4:1) medium resulted in detection of Cu(II) ions, exclusively. Further L6-Cu(II) complex was characterized via FTIR, FE-SEM, LCMS and supported by DFT studies. A significant structural modification has rendered the current probe as highly selective for Cu2+ ions, with ‘Turn-On’ response. The chemical receptor (L6) establishes 1:1 molar ratio with Cu(II) ions with binding constant of 6.0 × 104 M−1 and excellent detection limit of 20 nM. In addition, the sensitive reversible behavior of probe (L6) with two chemical inputs (Cu2+ and EDTA) contributes to the construction of an INHIBIT logic circuit. The Copper ion detection was effectively monitored for real-world samples like Black Tea with precise quantification of Copper(II) ions.

A Highly Efficient and Selective Glycine Based Schiff Base Fluorescent Probe for Dual Sensing of Zn(II) and Cu(II) and its Antibacterial Activity and BSA Interaction Studies

AbstractA mesogenic glycine based Schiff base compound of the type, (E)‐methyl 2‐((2‐hydroxy‐4‐(tetradecyloxy)benzylidene)amino)acetate (HL) has been successfully synthesized and characterized using analytical and spectroscopic techniques. The Schiff base compound was evaluated for chemosensor activity towards different metal ions using fluorescence spectroscopy. The experiment reveals highly efficient and selective “turn‐on” and “turn‐off” responses of the fluorescence intensity towards zinc(II) and copper(II), respectively, in presence of other metal ions. The binding constant and the stoichiometry ratio were determined using Benesi‐Hildebrand equation giving 1 : 1 stoichiometry. The limits of detection for both the metal ions were estimated from the fluorescence titration experiments. The reversibility nature of the Schiff base probe was also studied using EDTA as chelating ligand. The compound, HL exhibits two INHIBIT logic gates with chemical inputs (i) Zn2+ (IN1) and Cu2+ (IN2) and (ii) Zn2+ (IN1) and EDTA (IN2). An IMPLICATION logic gate was also obtained when Cu2+ (IN1) and EDTA (IN2) serve as chemical inputs. The compound was found to exhibit potent antibacterial activity and efficient binding interaction with BSA. Molecular docking studies were carried out in order to ascertain the degree of interaction and the nature of binding of the compound with the proteins.

Multifunctional Logic Operations Based Upon Congruent Ion Sensing Appended with a Strategic Molecular Device: Spectroscopic Approach

AbstractA multi‐responsive smart molecular system is constructed using a newly synthesized Salen molecule, 1,3‐bis((E)‐2,3,4‐trimethoxy benzylideneamino) propan‐2‐ol (TMBP), to selectively recognize the presence and absence of Cu2+ ions aided by another selective metal ion, Zn2+. The emission efficiency of the non‐emissive probe is selectively and significantly enhanced in presence of Zn2+, while the improved emission of probe‐Zn2+ complex is completely quenched upon interaction with Cu2+. Thus, the probe acts as a reporter molecule for the selective detection of Cu2+ in the co‐presence of Zn2+. Comprehensive spectroscopic studies indicate that Zn2+ ion‐coordination significantly reduces the flexibility of the Schiff base unit and the extent of photoinduced electron transfer which in turn enhance the fluorescence intensity. While Cu2+, a d9 system, induces paramagnetic quenching over the enhanced emission through stable ground‐state complexation and metal‐ligand charge transfer. The spectroscopic results are translated into the designing of a multifunctional smart‐molecular system that could function as YES, NOT, INHIBIT, PASS 0, TRANSFER and NOT TRANSFER logic gates. Finally, a blueprint of a smart molecular device is proposed to present the relay sensing of Zn2+ and Cu2+ through logical outputs that would work in‐sync with the spectroscopic results.

A 3D Phosphorescent Supramolecular Organic Framework in Aqueous Solution

AbstractSupramolecular organic framework (SOF) has recently garnered significant research interest in the field of luminescent materials. However, SOF with room‐temperature phosphorescence emission in solution is very rare due to the quenching of dissolved oxygen and free molecular motions, which would lead to nonradiative deactivation of triplet exciton in liquid state. In this work, a 3D cationic phosphorescent SOF is synthesized through host‐guest interaction between CB[8] and a tetrahedral monomer TBBP, which can rapidly adsorb anionic guests in solution. When anionic dyes are introduced, triplet to singlet Förster resonance energy transfer (TS‐FRET) in solution can be achieved, and delayed fluorescence with large Stokes shift can be realized. Additionally, when anionic drugs are introduced, the phosphorescence of TBBP‐CB[8] can be quenched due to charge transfer, enabling the detection of drugs through phosphorescence signals. Taking advantage of the fast adsorption property of 3D SOF, an INHIBIT logic gate with three inputs and two outputs is constructed. These findings provide a novel method to prepare phosphorescent functional materials and a new pathway to construct TS‐FRET system in solution.

Architecture of Easy-to-Synthesize and Superior Probe Based on Aminoquinoline Appended Naphthoquinone: Instant and On-Site Cu2+ Ion Quantification in Real Samples and Unusual Crystal Structure and Logic Gate Operations.

Easy-to-synthesize aminoquinoline (AQ) appended naphthoquinone (NQ)-based colorimetric and ratiometric probe (AQNQ) was successfully synthesized in one step with high yield and low cost, and was utilized to supply an effective solution to critical shortcomings encountered in Cu2+ analysis. The structure of AQNQ and its interaction with Cu2+ forming an unusual AQNQ-Cu complex were enlightened with single-crystal X-ray diffraction analysis and different spectroscopic methods. AQNQ-Cu complex is the first Cu2+ containing dinuclear crystal where the octahedral coordination sphere is fulfilled through the coordination of a NQ oxygen atom. AQNQ exhibited long-term stability (more than 1 month), superior probe ability toward Cu2+ with quite fast response (30 s), high selectivity among many ions, and limit of detection of 12.13 ppb that is significantly below the highest amount of Cu2+ allowed in drinking water established by both WHO and EPA. Ratiometric determination of Cu2+ using AQNQ was performed with high recovery and low RSD values for drinking water, tap water, lake water, cherry, and watermelon samples. Colorimetric on-site determination including smartphone and paper strip applications, IMPLICATION, and INHIBIT logic gate applications were successfully carried out. The reversibility and reusability of the response to Cu2+ ions with the paper strip application were examined for the first time.

Exploring the time-dependent and wavelength-guided tunable binary and ternary logic behaviours of a charge-transfer probe.

This study presents the development of a novel time-dependent logic behaviour system and a state-of-the-art inter-switchable ternary molecular logic system, comprising 3-input INHIBIT and 3-input TRANSFER logic gates driven by elementary chemical interactions. The absorption spectra of the probe molecule underwent versatile time-dependent changes upon the individual and simultaneous addition of two analytes, namely F- and CN-, leading to alterations in the logic behaviour observed at both the 295 nm (from AND to TRANSFER) and 400 nm bands (from OR to INHIBIT). Additionally, we explored the creation of wavelength-guided molecular logic systems that leverage reversible (F- and H2O) and irreversible (CN- and H2O) chemical interactions. By employing CN- and H2O as dual chemical inputs, we derived binary TRANSFER, 2-input PASS 0, and binary COMPLEMENT logic gates based on the opto-chemical responses at 295 nm, 400 nm, and 500 nm, respectively. Lastly, we introduced an innovative inter-switchable ternary molecular logic system, involving 3-input INHIBIT and 3-input TRANSFER logic gates, using F-, CN-, and H2O as ternary chemical inputs, capitalizing on the probes' versatile and distinct absorption responses at varying wavelengths (400 and 295 nm, respectively).

A rhodamine-6G based chromo and fluorogenic sensor for the selective turn-ON detection of Fe3+ in aqueous medium with potential applications as INHIBIT logic gate, memory device and live cell imaging

A novel rhodamine-6G based biocompatible chromo- and fluorogenic “OFF-ON” sensor L2, having amide based metal ion receptor, has been synthesized using Michael addition reaction and characterized by IR, NMR and HRMS spectroscopic studies. It exhibits an excellent selectivity and sensitivity towards Fe3+ in aqueous medium over mono- and di-valent and other trivalent metal ions. A 14-fold enhancement of fluorescence intensity was found upon addition of 11.5 equivalent Fe3+ ion into the probe L2 in H2O (pH 7.2, 10 mM HEPES buffer) with colour change from colourless to reddish yellow, providing an opportunity for naked eye detection of Fe3+. The corresponding binding constant Kf was evaluated to be (1.16 ± 0.04) x 104 M−1 with 1:1 stoichiometry. Quantum yields of L2 and [L2 - Fe3+] complex in H2O (pH 7.2, 10 mM HEPES buffer) were found to be 0.013 and 0.523, respectively using Rhodamine-6G as standard. LOD of L2 for Fe3+ detection in aqueous medium determined by 3σ/slope method was found to be 4.184 μM. Cyanide ion scavanges Fe3+ from [L2 - Fe3+] resulting quenching of fluorescence due to re-attainment of the non-fluorescent spirolactam ring form of the probe. As the sensing phenomenon is reversible, it helps to frame INHIBIT logic gate and memory devices.

Simple excited state intramolecular proton transfer (ESIPT) based probe for pH and selective detection of copper(II) ion in aqueous alkaline environment: Sensitivity, selectivity and logic behavior

A low molecular weight ESIPT-based probe was synthesized and tested for detecting pH, cations, and anions in aqueous solutions. The probe exhibited a good emission in water due to aggregation induced by π-π* stacking. It gave an “off–on” fluorescent response to higher pHs because of blocking the non-radiative ESIPT after deprotonating phenolic hydroxyl groups. Moreover, the fluorescence emission of the probe (water/ethanol = 3:1, pH 10) was quenched only by Cu2+ with limit of detection LOD = 3.2 μM. The stoichiometric ratio of the probe/Cu2+ complex was found to be 1:1. Furthermore, changes of the probe’s absorption and emission signals (as outputs) in response to the presence of H+ and HO– or Cu2+ and Br− stimuli (as chemical inputs) mimics INHIBIT, IMPLICATION and NOT TRANSFER logic gates.

An azine-based chromogenic, fluorogenic probe for specific cascade detection of Al3+ and PO43- ions

An azine-based chromo-fluorogenic sensor, 2,2′-((1E,1′E)-hydrazine-1,2-diylidenebis(methanylyidene)) bis(4-nitrophenol) (DBMN), has been introduced for cascade detection of Al3+ and PO43- ions with high selectivity and sensitivity with a detection limit in the nM to μM range. Upon introducing Al3+ ions into the DBMN solution, a remarkable colorimetric change from yellow to colorless has been noticed in the naked eye due to inhibiting the intramolecular charge transfer process. A 120 times photoluminescence intensity enhancement displaying bluish-green fluorescence under the exposure of a 365 nm UV lamp is observed because of chelation-enhanced fluorescence (CHEF) from the solution of Al3+ ions chelated DBMN complex, which is also well-supported by the color chromaticity diagram. Al3+ ions chelated DBMN complex is selective and sensitive to detecting PO43- ions by rebirthing DBMN. A paper strips-based test kit has been fabricated for on-site cascade detection of Al3+ and PO43- ions, respectively. By employing either Al3+ and PO43- ions as single chemically encoded input and photoluminescence intensity as optical output, we have framed YES and NOT single input and single output opto-chemical logic circuits. Also, based on the photoluminescence off–on-off mechanism, we have designed two inputs and one output-based INHIBIT logic gate with the help of sequential addition of Al3+ and PO43- ions as the two chemically encoded inputs and the luminosity at 500 nm as a single output. Also, a set-reset memorized molecular device has been framed based on photoluminescence as the optical output due to the sequential addition of Al3+ and PO43- ions in the DBMN solution.

Sequence-Independent Logical Regulation of the Assembly and Disassembly of DNA Polyhedra.

Controlling the self-assembly of DNA nanostructures using rationally designed logic gates is a major goal of dynamic DNA nanotechnology, which could facilitate the development of biomedicine, molecular computation, et al. In previous works, the regulations mostly relied on either toehold-mediated strand displacement or stimuli-driven conformational switch, requiring elaborately-designed or specific DNA sequences. Herein, we reported a facile, base-sequence-independent strategy for logically controlling DNA self-assembly through external molecules. The INHIBIT and XOR logic controls over the assembly/disassembly of DNA polyhedra were realized through cystamine (Cyst) and ethylenediamine (EN) respectively, which were further integrated into a half subtractor circuit thanks to the sharing of the same inputs. Our work provides a sequence-independent strategy in logically controlling DNA self-assembly, which may open up new possibilities for dynamic DNA nanotechnology.

2-Naphthol scaffold as selective colorimetric and fluorescence ‘turn-on’ sensor of PO4 3-

ABSTRACT 1-(Pyridin-2-yl-hydrazonomethyl)-naphthalen-2-ol (PNOH) is a naphthalene-based fluorescence chemo-sensor for PO4 3-. The probe (PNOH) is spectroscopically characterised and the chemo-sensing mechanism has been demonstrated through 1H NMR, UV-Vis absorption and both steady-state and time resolved fluorescence study. Fluorescence ‘turn-on’ sensing knack of PNOH towards PO4 3- ion has been explained due to emission from the excited PNO– ion, formed upon transfer of phenolic proton of PNOH to PO4 3- ion in the excited state. The 1:1 stoichiometry of PNOH-PO4 3- complex is observed from Job’s plot based on UV-Vis titration and the complex shows distinct yellowish-green colour to be used as colorimetric sensor for PO4 3-. Limit of detection (LOD) of PNOH towards PO4 3- is found to be 0.35 µM. It is also demonstrated that the probe can be used to fabricate a convenient and efficient PO4 3- paper test kits as well as molecular INHIBIT logic gate.

An Off‐On‐Off Benzoxazole‐Based Fluorosensor for Relay Detection of Al3+ Ions and Explosive Nitroaromatic Compounds

AbstractDeveloping fluorosensors for the efficient detection of aluminium (Al3+) ions and electron‐deficient nitroaromatic compounds (NACs) is in high demand but challenging. This report introduces a benzoxazole‐based off‐on‐off fluorosensor for the cascade detection of Al3+ ions and electron‐deficient NACs. Upon addition of Al3+ ions, the probe BPMP displays a bright blue fluorescence under the exposure of 365 nm UV light radiation in an H2O/DMSO (1 : 1 v/v) medium due to the chelation of Al3+ ions disrupting the ESIPT process involved in probe BPMP. The detection limit for Al3+ ions is found to be 13 nM, which is significantly lower than many chemosensors available in the literature. The 1 : 1 stoichiometry of the chelated complex between BPMP and Al3+ ions is confirmed by Job′s plot and also by 1H NMR titration investigation. More importantly, the Al3+ ions chelated BPMP complex is further used as a fluorescent turn‐off probe for the detection of electron‐deficient NACs with the detection as low as 10−7 M. Based on these chemically encoded inputs and the corresponding optical output, we have constructed one input and one output based YES, and NOT logic gate with BPMP and BPMP‐Al3+ complex as input respectively and also dual inputs and single optical output‐based INHIBIT logic gates. Also, BPMP‐doped paper strips‐based test kit analysis has been demonstrated as a displayable photonic device for on‐spot detection. The performance of BPMP and Al3+ ions chelated BPMP complex toward Al3+ ions and electron‐deficient NACs demonstrated that BPMP could be served as a sensitive probe and could be employed for real sample analysis.

New Water-Soluble Poly(propylene imine) Dendrimer Modified with 4-Sulfo-1,8-naphthalimide Units: Sensing Properties and Logic Gates Mimicking.

A new water-soluble poly(propylene imine) dendrimer (PPI) modified with 4-sulfo-1,8-naphthalimid units (SNID) and its related structure monomer analog (SNIM) has been prepared by a simple synthesis. The aqueous solution of the monomer exhibited aggregation-induced emission (AIE) at 395 nm, while the dendrimer emitted at 470 nm due to an excimer formation beside the AIE at 395 nm. Fluorescence emission of the aqueous solution of either SNIM or SNID was significantly affected by traces of different miscible organic solvents, and the limits of detection were found to be less than 0.05% (v/v). Moreover, SNID exhibited the function to execute molecular size-based logic gates where it mimics XNOR and INHIBIT logic gates using water and ethanol as inputs and the AIE/excimer emissions as outputs. Hence, the concomitant execution of both XNOR and INHIBIT enables SNID to mimic digital comparators.

Solution-based carbon quantum dots as electrochemical “on–off” switch in aqueous medium: Engineering of a sustainable green sensor and its computational investigation

It is crucial to establish sensitive electroanalysis of pollutants in water environments, but this is difficult due to their redox inertness and uncertain detection methods. We herein report an electrochemical switch ‘on–off sensor for the selective detection of Hg(II) and amoxicillin (AMX) based on a switch platform system. Our design used a carbon quantum dot (CQD)-based sensing probe (SP) to intensify the electrochemical signal due to its excellent conductivity. The “switch-on” state was attained by introducing the Hg(II) ions and sensing probe (SP) onto the electrode surface to facilitate electron transfer. The modified electrode signifies an excellent electrocatalytic activity of Hg (II), giving sharp anodic and cathodic peaks at 0.53 and 0.42 (V vs. SCE), respectively. Upon addition of AMX, it cleaves the SP into fragments from the sensing interface, hindering the electrochemical signal to create a “switch-off” state. As expected, the SP displayed a desirable linear response range from 0.0 to 100 nM and the detection limit down to 15.0 nM. Density functional theory (DFT) calculations confirm that the binding energy of the AMX with the Hg(II) ion is greater than that of SP and Hg(II). Moreover, the probe showed excellent stability and reproducibility with Hg(II) selectively; thus, it confines great scope for application in environmental water sciences. Further, the switch “on–off” sensing behavior of SP providing two chemical inputs (Hg (II) and AMX) helps to set up an INHIBIT logic gate. A series of experiments, including DFT and electrochemistry, demonstrate the detection mechanism and enhanced electrochemical sensitivity. This sustainable engineering approach creates a perfect sensor using a carbon quantum dots-based sensing probe from waste paper.