Using eugenol scaffold to explore the explosive sensing properties of Cd(II)-based coordination polymers: experimental studies and real sample analysis.

Eugenol, the major constituent of clove oil, has been explored as an essential natural ingredient for ages owing to its versatile pharmacological properties. However, to date, the coordination chemistry of eugenol derivatives has not been much explored. In the present work, an eugenol-based Schiff base ligand (HL) was synthesized and structurally confirmed through ESI-MS, NMR, and FT-IR spectroscopy studies. Consequently, the N,O-donor chelating ligand HL was coordinated with Cd2+, in the presence of bridging pseudohalides (thiocyanate, SCN-, and dicyanamide, N(CN)2-) to synthesize two luminescent coordination polymers (CPs 1 and 2): [Cd2(L)2(X)2]n (where HL = 4-allyl-2-(((2-(benzylamino)ethyl) imino)methyl)-6-methoxyphenol and Xs are bridging pseudohalides, i.e., SCN- and N(CN)2-) on a Cd-eugenol scaffold. The CPs depicted structural diversity, bulk-phase purity, thermal stability, and the presence of interlayer supramolecular C-H⋯π interactions together with C-H⋯S (for CP 1) and C-H⋯N (for CP 2) interactions. The CPs further exemplified themselves as selective and sensitive 'turn-off' probes towards trinitrophenol (TNP) (quenching efficiency: 82.02% and 83.86% for 1 and 2) among a pool of hazardous nitroaromatic compounds (NACs). Accordingly, 1 and 2 exhibited an ultralow limit of detection (LOD) of 0.29 and 0.15 µM, with high quenching constants (KSV) of 5.91 × 104 and 17.60 × 104 M-1, respectively. In addition, TNP sensing events were evidenced to be recyclable and exhibited fast response (∼31 s, 1, and ∼40 s, 2), which increased its real-world viability. Vapor phase TNP sensing was also accomplished upon drop-casted CP films. Experimental investigations and theoretical DFT study confirmed the cooperative occurrence of RET-IFE-PET-collisional quenching and non-covalent π⋯π stacking as key factors involved in the TNP sensing performance. The competency of 1 and 2 in the detection of TNP from several complex environmental matrices (CEMs), viz. matchstick powder, river and sewage water, and soil specimens, was also established with good recovery (∼66-86% and ∼68-93% for 1 and 2, respectively) and high KSV values (3.90-11.39 × 104 and 6.17-18.79 × 104 M-1 for 1 and 2, respectively).

Mixed N,O-donor Directed Blue Emissive Nano-dispersed Mesoporous Mn(II)-MOF: Dual Sensing Probe for Recyclable and Ultrasensitive ppb-Level Recognition of TNP and Cr(VI)-Oxoanions.

A new mesoporous Mn(II)-MOF [Mn2(phen)2(nia)2]∞ with 4-c uninodal net topology and reiterating rectangular channels in its cargo-net like extension was synthesized using π-conjugated phenanthroline (phen) and syn-syn bridging 5-nitroisopthalic acid (nia) linkers. The MOF (1) exhibited phase purity, uniform morphology, photo and thermal stability, and robustness; duly triggered by the exceptional framework rigidity via intermolecular H-bonding and interlayer π-π stacking interactions. The bright-blue luminescence of the MOF nano-dispersion was explored for sensitive, specific and ultrafast detection of trinitrophenol (TNP) with extremely low LOD (90.62 nM), high KSV (18.27×104 M-1) and Kq (4×1014 M-1s-1). The vapor-phase TNP sensing was also accomplished. Additionally, 1 served towards discriminatory, aqueous-phase monitoring of Cr(VI)-oxoanions, depicting LODs: 36.08 and 35.70 ppb; KSV: 3.46×104 and 4.87×104 M-1; Kq: 3.26×1013 M-1s-1 and 4.31×1013 M-1s-1; and response time: 32 and 40s for CrO4 2- and Cr2O7 2- respectively. The quenching mechanisms (i. e., RET, PET, IFE, weak interactions, collisional quenching and π⋅⋅⋅π stacking) was explained from several experimental investigations and theoretical DFT calculations. The recyclable sensing events and quantification from complex environmental matrices with admirable recovery rates and high KSV (13.02-22.44×104; ~6.31-10.98×104 and ~6.60-11.42×104 M-1 for TNP, CrO4 2- and Cr2O7 2-) undoubtedly advocated the consistency of the probe.

Integration of a Bismuth-Based Tris-Mononuclear Complex with 2D Functional Materials for Highly Efficient and Durable Aqueous Electrocatalytic Hydrogen Evolution.

The eminence of transitioning from traditional fossil fuel-based energy resources to renewable and sustainable energy sources is most evidently crucial. The potential of hydrogen as an alternative energy source has specifically focuses the electrocatalytic water splitting (EWS) as a promising technique for generating hydrogen. Development of efficient electrocatalysts to facilitate the EWS process while rationalizing the limitations of noble metal catalysts like platinum has become one of the daunting tasks. Consequently, porous functional materials such as metal complexes (MCs) and graphene oxide (GO) can act as potential catalysts for EWS. Therefore, a composite of GO and a mononuclear bismuth metal complex is synthesized through in situ facile synthesis, which is further utilized as an efficient electrocatalyst for the hydrogen evolution reaction (HER). Several potential electrocatalytic MC@GO composite (BMGO-3,5,7) materials were prepared with compositional variation of GO (3, 5, and 7 wt %). The experimental results demonstrate that the BMGO5 composite exhibits excellent HER activity with a low overpotential value of 105 mV at 10 mA cm-2 and a low Tafel slope of 44 mV dec-1 in 1 M KOH solution. Furthermore, a comprehensive investigation on the potentiality of the BMC-GO composite for hydrogen evolution from river water splitting was performed in order to address the issue of freshwater depletion. Inclusion of a mononuclear MC for facile synthesis of functional GO-based efficient electrocatalyst material is very scanty in the literature. This unique approach could assist future research endeavors toward designing efficient electrocatalysts for sustainable renewable energy generation. This is one of the first of its kind, where mononuclear MCs were utilized to develop GO-based functional composite materials for efficient electrocatalysis toward sustainable renewable energy generation.

CuAs2O4: Design, Hydrothermal Synthesis, Crystal Structure, Photocatalytic Dye Degradation, Hydrogen Evolution Reaction, Knoevenagel Condensation Reaction, and Thermal Studies.

CuAs2O4 has been explored as a heterogeneous catalyst in the fields of photocatalysis, electrocatalysis, and solvent-free organic transformation reactions. The homogeneity has been successfully attained for the first time by designing a pH-assisted hydrothermal synthesis technique. Single-crystal X-ray diffraction studies reveal that no phase transition has been observed by lowering the temperature up to 103 K with no existence of satellite reflections. The crystal structure exhibits tetragonal symmetry with space group P42/mbc and consists of [CuO6] octahedra and [AsO3E] tetrahedra (E represents the stereochemically active lone pair). Structural investigation shows a cylindrical void inside the structure, which could lead to interesting physical and chemical properties. The photocatalytic dye degradation efficiency with methylene blue (MB) showed ∼100% degradation, though the degradation efficiency increased by 2-fold with the addition of 6% H2O2. The reusability of the catalyst up to the 10th cycle with ∼35% MB dye degradation has been established. It can exhibit HER activity with a low overpotential of 165 mV with respect to RHE to attain the current density of j = 10 mA cm-2. SEM and TEM revealed rod-shaped particles, which supported the large number of catalytic active sites. The structural consistency of the catalyst after photodegradation and HER studies is confirmed by the PXRD pattern. XPS confirms the oxidation state of Cu and As in the compound. The catalytic activity toward the Knoevenagel condensation reaction at moderate temperature under solvent-free condition is also studied. TG-DTA shows an endothermic minimum (Tmin) at 436 °C due to the mass loss of As2O3.

Exploitation of a 1D coordination polymer as a portable kit for an eye-catching fluorometric response towards sensing of trivalent cations.

The development and utilization of coordination polymers (CPs) have drawn interest for potential applications in different fields. Detection of metal ions in efficient and selective manners is an important field of research. It paves the way to protect human health by balancing toxic metal ions and biologically active metal ions in the atmosphere. In this regard, a new one-dimensional (1D) 4-(1-naphthylvinyl)pyridine (4-nvp) based CP [Cd(NCS)2(4-nvp)2]n (1) was synthesized and characterized structurally by single-crystal X-ray diffraction. Interestingly, this 1D CP underwent supramolecular aggregation via π⋯π stacking interactions, which specifically generated an environment for a potent "turn on" response in the presence of trivalent cations (Fe3+, Al3+, and Cr3+) in the nanomolar range but remained silent in the presence of other metal ions. Density functional theory (DFT) computations and X-ray photoelectron spectroscopy (XPS) were performed to establish the sensing phenomena. Fascinatingly, utilizing the sensitivity of 1 in an aqueous medium, a hands-on portable cotton swab kit was developed for instant identification of these three important trivalent metal cations.

Facile construction of an anthracene-decorated highly luminescent coordination polymer for the selective detection of explosive nitroaromatics and the mutagenic pollutant TNP.

Explosive nitroaromatic compounds (epNACs) are a group of chemicals that have caused significant human casualties through terrorist attacks and they also pose health risks. For the benefit of homeland security and environmental health, there is room for advancing research on the precise detection of epNACs. Coordination polymers (CPs) successfully serve this purpose because of their binding abilities and quenching capabilities. In this regard, a one-dimensional (1D) CP [Zn(bdc)(avp)2(H2O)]n (1; H2bdc = 1,4-benzenedicarboxylic acid and avp = 4-[2-(9-anthryl)vinyl]pyridine) was synthesized, which remarkably demonstrated extremely efficient ratiometric and selective sensing capacity toward epNACs and the mutagenic pollutant 2,4,6-trinitrophenol (TNP) with a quick response. Density functional theory (DFT) calculations provided a thorough analysis of the mechanistic routes behind the quenching reaction. Herein, geometrically accessible interaction sites were strategically decorated using anthracene moieties, allowing the quick and precise detection of explosive nitro derivatives and the carcinogenic pollutant TNP with increased sensitivity.

Drug delivery using biocompatible covalent organic frameworks (COFs) towards a therapeutic approach.

Covalent organic frameworks (COFs) are constructed exclusively with lightweight organic scaffolds, which can have a 2D or 3D architecture. The ease of synthesis, robust skeleton and tunable properties of COFs make them superior candidates among their counterparts for a wide range of uses including biomedical applications. In the biomedical field, drug delivery or photodynamic-photothermal (PDT-PTT) therapy can be individually considered a potential parameter to be investigated. Therefore, this comprehensive review is focused on drug delivery using COFs, highlighting the encapsulation and decapsulation of drugs by COF scaffolds and their delivery in biological media including live cells. Versatile COF scaffolds together with the delivery of several drug molecules are considered. We attempted to incorporate the status of drug encapsulation and decapsulation considering a wide range of recent publications.

Anion-directed structural tuning of two azomethine-derived Zn2+ complexes with optoelectronic recognition of Cu2+ in aqueous medium with anti-cancer activities: from micromolar to femtomolar sensitivity with DFT revelation.

Herein, two novel mononuclear transition metal Zn2+ complexes i.e. [Zn(HL)(N3)(OAc)] (NS-1) & [Zn(HL)2(ClO4)2] (NS-2) have been synthesised using a tridentate clickable Schiff base ligand, HL (2-methyl-2-((pyridin-2-ylmethyl)amino)propan-1-ol), and the polyatomic monoanions N3- and ClO4- for NS-1 and NS-2 respectively. Interestingly, NS-1 and NS-2 have been explored for the detection of Cu2+ with an LOD of 48.6 fM (response time ∼6 s) and 2.4 µM respectively through two mutually independent pathways that were studied using sophisticated methods like UV-Vis, cyclic voltammetry, ESI-MS etc. with theoretical DFT support. Herein, both chemosensors are equally responsive towards the detection of Cu2+ in aqueous as well as other targeted real field samples with appreciable recovery percentage (74.8-102%), demonstrating their practical applicability. Moreover, the detection of unbound Cu2+ in a human urine specimen was also analysed which may be helpful for the diagnosis of Cu2+-related disorders like Wilson's disease. Taking one step ahead, TLC strips have been employed for on-field detection of the targeted analytes by contact mode analysis. Additionally, the anti-cancer activity of these complexes has also been studied on breast cancer cells with the help of the MTT assay. It has been found that at a 0.5 mM dose, both NS-1 and NS-2 could kill 81.4% and 73.2% of cancer cells respectively. However, it has been found that NS-1 destroys normal cells together with cancer cells. Hence, NS-2 could be administered as a better anticancer drug for MDA-MB-231 cancer cells in comparison with NS-1. In a nutshell, the present work describes how anion-directed synthesis of two architecturally different metal complexes leads toward the detection of the same analyte via an independent chemodosimetric pathway along with their anti-cancer activities on breast cancer cells.

AIEE activated Pyrene-Dansyl coupled FRET probe for discriminating detection of lethal Cu2+ and CN-: Bio-Imaging, DNA binding studies and prompt prognosis of Menke's disease.

In present work a pyrene-dansyl dyad functionalized chemoreceptor, DPNS is unveiled towards ultrasensitive chromo-fluorogenic detection of heavy and transition metal ions (HTMs) like Cu2+ and pernicious CN-. It demonstrated distinct chromogenic responses; colorless to faint yellow (Cu2+), intense yellow (CN-) from contaminant aqueous sources. Cu2+ instigated alteration in DPNS fluorescence from feeble emission to sparkling green with LOD: 37.75 × 10-9 M, cyan emission for CN- having LOD 61.51 × 10-8M. In particular, chemical scaffold of DPNS consists of -C = N, O = S = O donor entitities that escalates overall polarity thereby providing an excellent binding pocket for simultaneous Cu2+ and CN- recognition with distinct photophysical signaling. Impressively, presence of two fluorophoric moieties triggers FRET, CHEF phenomenon. The conceivable host:guest interactive pathway is manifested by LMCT- FRET-PET-CHEF, C = N isomerization for Cu2+ and ICT-H-bonding for CN-. An exquisite experimental and theoretical corroboration further strengthened the recognition phenomenon. In addition owing to pyrene excimer formation, DPNS exhibits AIEE with increasing water fraction. Notably, DPNS could successfully undergo intracellular tracking of Cu2+ in Tecoma Stans, Peperomia Pellucida. DPNS•••Cu2+ adduct displayed significant intercalative DNA binding activity rationalized by spectral investigation, competitive EB binding, viscosity study. The overall findings, excellent properties endows DPNS a potential contender towards discriminative detection of Cu2+ and CN- like toxic industrial contaminants.

A strategically synthesized arseno-discriminatory tetra-phenoxido hetero-trinuclear complex envisioned for the recognition of iAs and oAs from Oryza sp. and aquatic crustaceans.

A heterotrimetallic [MnII(CuII)2(C18H18N2O2)2] complex VBCMERI has been unveiled herein to monitor its synergistic propensity towards aqueous phase As3+ (iAs and oAs) detection. VBCMERI was structurally probed by numerous analytical tools like ESI-MS, FT-IR, and SCXRD. The aqueous phase selective chromogenic alteration of the sensory probe from greenish-yellow to colorless was observed owing to interaction with As3+ (cationic form, iAs). This phenomenon can be ascribed to the displacement of the Mn2+ center with As3+, which has further been experimentally validated through cyclic voltammetric titration studies, FT-IR, and ESI-MS, and theoretically corroborated with density functional theory calculations. Interestingly, aqueous phase selective turn-on fluorogenic enhancement of the sensory probe was observed upon interaction with AsO2- (anionic form, iAs) owing to the displacement of the arsenite anion with the pivalic acid group. The distinct chromogenic alteration from greenish-yellow to colorless and the fluorogenic enhancement of VBCMERI upon interaction with the respective As3+ (iAs) and AsO2- (iAs) were successfully implemented for monitoring arsenic contamination in groundwater samples and diverse types of Oryza sp. grains from the assorted arsenic-affected zones. The competitive accumulation of arsenobetaine (oAs) in the exoskeleton and muscles of aquatic crustaceans (herein, Penaeus sp.) can be distinctly differentiated based on the turn-on fluorogenic response. Based on the sensing response and competitive accumulation tendency of different forms of arsenic in different environments, arseno-adducts with VBCMERI have been theoretically modeled for corroboration with experimental findings. The VBCMERI-AsO2- adduct was also highly efficient in regenerating the VBCMERI sensor selectively in the presence of contaminants like Pb2+. This reversible behavior was further exploited to mimic a molecular-level 3-input-2-output logic gate ensemble.

Explicating the recognition phenomenon of hazardous nitro-aromatic compound from contaminated environmental and cellular matrices by rationally designed pyridine-functionalized molecular probes.

In the quest of recognizing hazardous nitro-aromatic compounds in water, two pyridine-functionalized Schiff-base chemosensors, DMP ((E)-N-(3,4-dimethoxybenzylidene)(pyridin-2-yl)methanamine)) and MP (4-((E)-((pyridin-2-yl)methylimino)methyl)-2-ethoxyphenol) have been synthesized to detect mutagenic 2,4,6-Trinitrophenol (TNP) in soil, water as well as cellular matrices by producing turn-off emission responses as a combined consequence of PET and RET processes. Several experimental analyses including ESI-MS, FT-IR, photoluminescence, 1H NMR titration, and the theoretical calculations ascertained the formation and sensing efficacies of the chemosensors. The analytical substantiations revealed that structural variation of the chemosensors played a significant role in improving the sensing efficiency, which would certainly be worthwhile in developing small molecular TNP sensors. The present work depicted that the electron density within the MP framework was more than that of DMP due to the intentional incorporation of -OEt and -OH groups. As a result, MP represented a strong interaction mode towards the electron-deficient TNP with a detection limit of 39 µM.

A Ni-MOF as Fluorescent/Electrochemical Dual Probe for Ultrasensitive Detection of Picric Acid from Aqueous Media.

A water-stable, microporous, luminescent Ni(II)-based metal-organic framework (MOF) (Ni-OBA-Bpy-18) with a 4-c uninodal sql topology was solvothermally synthesized using mixed N-, O-donor-directed π-conjugated co-ligands. The extraordinary performance of this MOF toward rapid monitoring of mutagenic explosive trinitrophenol (TNP) in aqueous and vapor phases by the fluorescence "Turn-off" technique with an ultralow detection limit of 66.43 ppb (Ksv: 3.45 × 105 M-1) was governed by a synchronous occurrence of photoinduced electron transfer-resonance energy transfer-intermolecular charge transfer (PET-RET-ICT) and non-covalent π···π weak interactions, as revealed from density functional theory studies. The recyclable nature of the MOF, detection from complex environmental matrices, and fabrication of a handy MOF@cotton-swab detection kit certainly escalated the on-field viability of the probe. Interestingly, the presence of electron-withdrawing TNP decisively facilitated the redox events of the reversible NiIII/II and NiIV/III couples under an applied voltage based on which electrochemical recognition of TNP was realized by the Ni-OBA-Bpy-18 MOF/glassy carbon electrode, with an excellent detection limit of ∼0.6 ppm. Such detection of a specific analyte by MOF-based probe via two divergent yet coherent techniques is unprecedented and yet to be explored in relevant literature.

Electrochemical Nanosensors for Sensitization of Sweat Metabolites: From Concept Mapping to Personalized Health Monitoring.

Sweat contains a broad range of important biomarkers, which may be beneficial for acquiring non-invasive biochemical information on human health status. Therefore, highly selective and sensitive electrochemical nanosensors for the non-invasive detection of sweat metabolites have turned into a flourishing contender in the frontier of disease diagnosis. A large surface area, excellent electrocatalytic behavior and conductive properties make nanomaterials promising sensor materials for target-specific detection. Carbon-based nanomaterials (e.g., CNT, carbon quantum dots, and graphene), noble metals (e.g., Au and Pt), and metal oxide nanomaterials (e.g., ZnO, MnO2, and NiO) are widely used for modifying the working electrodes of electrochemical sensors, which may then be further functionalized with requisite enzymes for targeted detection. In the present review, recent developments (2018-2022) of electrochemical nanosensors by both enzymatic as well as non-enzymatic sensors for the effectual detection of sweat metabolites (e.g., glucose, ascorbic acid, lactate, urea/uric acid, ethanol and drug metabolites) have been comprehensively reviewed. Along with this, electrochemical sensing principles, including potentiometry, amperometry, CV, DPV, SWV and EIS have been briefly presented in the present review for a conceptual understanding of the sensing mechanisms. The detection thresholds (in the range of mM-nM), sensitivities, linear dynamic ranges and sensing modalities have also been properly addressed for a systematic understanding of the judicious design of more effective sensors. One step ahead, in the present review, current trends of flexible wearable electrochemical sensors in the form of eyeglasses, tattoos, gloves, patches, headbands, wrist bands, etc., have also been briefly summarized, which are beneficial for on-body in situ measurement of the targeted sweat metabolites. On-body monitoring of sweat metabolites via wireless data transmission has also been addressed. Finally, the gaps in the ongoing research endeavors, unmet challenges, outlooks and future prospects have also been discussed for the development of advanced non-invasive self-health-care-monitoring devices in the near future.

Metal-organic frameworks/cellulose hybrids with their modern technological implementation towards water treatment.

Metal-organic frameworks (MOFs) are amongst the most attractive porous polymeric networks with appealing properties. However, their inherent fragility, powder nature, low processibility, and handling present some exceptional challenges for high-tech commercial applications. Currently, economic and environmental concerns drive the development of some bioinspired polymeric matrices containing MOFs. As an artifact, the availability of previously unattainable properties is negotiated by conjugating cellulosic materials with crystalline MOFs. Thus, multi-dimensional organic-inorganic hybrid composites are formed with high electrical, optical, mechanical, and thermal features. These MOF/cellulose hybrids, known as CelloMOFs (cellulose MOFs), have remarkable mechanical properties with tunable porosities, specific surface area and accessible active sites, making them ideal for real-world troubleshooting applications such as wastewater treatment, chemical sensing, energy storage, and so on. In this review, current state-of-the-art strategic synthesis routes for fabrication of MOF/cellulose composites with a specific focus on CelloMOFs as a potential tool for mitigation of the targeted emerging water contaminants have been done under the same umbrella, which has previously been less explored. Streamlining discussions on general properties such as raw material selection, structural analysis of cellulose, availability of surface functional groups, cellulose-metal node interactions, cellulose charging, and so on have been emphasized, as has integration with robust MOFs. A better understanding of these fundamental properties is critical because they will have a significant impact on the performance of MOF/cellulose composites in a variety of applications. Furthermore, at the end of this review, the challenges and perspectives of using CelloMOFs have been discussed in a concise manner in order to improve their practical utility rather than just concept mapping.

Selective Low-Level Detection of a Perilous Nitroaromatic Compound Using Tailor-Made Cd(II)-Based Coordination Polymers: Study of Photophysical Properties and Effect of Functional Groups.

Three coordination polymers (CPs 1-3) are prepared based on diverse electron-donating properties and coordination arrangements of conjugated ligands. Interestingly, this is also reflected in their photophysical properties. The distinguishable high emissive nature of the luminescent coordination polymer shows its potentiality toward the detection of the perilous substance 2,4,6-trinitrophenol (TNP) or picric acid (PA). TNP has a higher propensity among explosive nitroaromatic compounds (epNACs) due to its significant π···π interaction with the free benzene moieties present in the CPs. Among CPs 1-3, 2 exhibits the highest sensitivity and selectivity toward TNP because of the most favorable π-π stacking with the conjugated organic linker. The calculated limit of detection (LOD) and corresponding quenching constant (KSV) from the Stern-Volmer (SV) plot for 1, 2, and 3 are found to be 0.68 µM and 7.49 × 104 M-1, 0.41 µM and 8.01 × 104 M-1, and 1.18 µM and 8.1 × 104 M-1, respectively. The fluorescence quenching mechanism is also highly influenced by their structure and coordination arrangement.

Regioselective synthetic approach for key precursors of 6-arylbenzo[c]phenanthridin-10-ol derivatives: a useful compound for selective chromogenic recognition of fluoride.

A regioselective synthetic strategy for 6-aryl-8,9-dihydrobenzo[c]phenanthridine-10(7H)-ones (4) is accomplished using a one-pot four-component reaction by fine-tuning the reaction temperature. DMSO is excellently used as a reactant-cum-solvent to introduce a carbonyl functionality regioselectively at the C-10 position of the benzophenanthridine backbone, via an MCR, which is unknown yet. The elegant features of this strategy are the formation of two CC, one CN, and one CO bonds in a single step, without using a base and an activator for the oxygenation process. Then, a few compounds (4) are easily aromatised to achieve 6-arylbenzo[c]phenanthridin-10-ol derivatives (7) using I2/DMSO at 100 °C. Nay, a dangling hydroxyl group in 4s, 4u, 4x, and 4z helped them to be employed as promising 'naked eye' colorimetric chemosensors for fluoride with limits of detection of 0.65, 0.60, 0.34, and 2.2 ppm, respectively. Moreover, the reversibility of the chemosensors makes them suitable for combinatorial INHIBIT logic gate formulation. The compounds have also been employed for solid-state F- detection via the spot TLC test.

"Caught in the Act" @ disruption of A-ET-E process in the recognition of F- by a lamellar EuIII-MOF in heterogeneous manner with logic gate construction: From protagonist idea to implementation world.

Development of cost-effective and reliable fluoride sensor for assessing water quality of natural water samples is of immense importance in developing countries as they can provide an easy platform for safeguarding human health. These sensors should be as simple as possible to be fabricated locally by layman. In this context, EuIII-based MOFs provide trustable platform with bright luminescence in the visible region due to their absorbance-energy transfer-emission (A-ET-E) process. Herein the designed synthesis of a 2D porous coordination polymer, Eu@CMERI, has been carried out following a solvothermal reaction route. The compound shows selective "turn-off" sensing of fluoride in heterogeneous manner from purely aqueous phase and other biological matrices with a detection limit of 28.4 ppb and it carries enormous importance for drinking water analysis under internal regulations. Prohibition of A-ET-E cycle of the EuIII-MOF is proposed to be the prime reason for fluorescence quenching upon interaction with F-. DFT studies also revealed that lowest △EHOMO-LUMO and highest chemical potential value (µ) of F- are the driving forces for selectivity of EuIII-MOF towards the targeted anion. The high stability of the porous frameworks along with its interesting sensing features, including fast response and wide linear detection range etc. instigated us not to restrict the chemistry of EuIII-MOFs at protagonist idea rather to explore its application to real-world analysis. Based on the fluorescence signal exhibited by the targeted analyte, an integrated AND-OR logic gate has also been fabricated which depicts its applicability in molecular electronics. In view of the modular design principle of our polymeric probe, the proposed strategy could open a new horizon to construct powerful sensing materials for ultrafast detection of other important pollutants in the domain of supramolecular chemistry in coming days.

Strategic optimization of phase-selective thermochemically amended terra-firma originating from excavation-squander for geogenic fluoride adsorption: a combined experimental and in silico approach.

An inimitable adsorbent "FI-TM-BWCC," emanated from meta-phase-selective thermochemical modulation of excavation-squander (mine waste)-derived terra-firma (blackish white china clay, i.e., BWCC), is explored in the present work for fluoride (F-) adsorption purpose. FI-TM-BWCC portrayed an excellent adsorption efficiency (95% removal capacity and Qe: 99 mg/g, at initial adsorbate dose: 10 mg/L, pH: 7±0.5, adsorbent dosage: ~600 mg, exposure time: 60 min). At identical experimental conditions, the F- scavenging phenomenon was superior than two analogous adsorbents: (i) biopolymer chitosan and glutaraldehyde cross-linked BWCC (CG@BWCC, wherein F- removal efficiency: 74%) and (ii) meta-phase-selective thermally moduled BWCC (TM-BWCC, removal efficiency: 75%). BWCC predominantly comprises kaolinite and a trace amount of anatase along with prime elemental compositions: 41.71% Al2O3, 49.80 % SiO2, 4.25% Fe2O3, and 3.93% TiO2, as revealed by PXRD and XRF analyses. The thermochemical modulation pathway significantly escalated the BET surface area of BWCC (~11.92 m2/g, avg. pore radius: 23.64 Å, i.e., mesoporous in nature) to FI-TM-BWCC (216.95 m2/g, avg. pore radius: 31.41 Å). The fluoride-adsorbed F-•••FI-TM-BWCC species revealed a reduced surface area of 21.5 m2/g, which was explained in the light of ion exchange pathway on FI-TM-BWCC's non-uniform surface (surface roughness/SA of 1597 nm, reduced to 1179 nm after F- uptake). The spontaneous F-•••FI-TM-BWCC interaction (ΔG0 = -6.25 kJ) occurred following chemisorption-controlled ion exchange (CCIE) pathway as appearance of a F1s band at 685.5 eV was rationalized for Si-F bond formation; corroborating pseudo second-order (PSO) kinetics and resembling Freundlich isotherm. The usefulness of FI-TM-BWCC was diversified through field validation with natural groundwater specimens and proposition of a gravity-fed defluoridation unit. The flow rate was documented to be ~11 liters per hour (LPH) by implementing viscous turbulence fluent model. The experimental findings certainly followed the premise conventions of sustainability metrics upholding socio-economic equipoise.

Unveiling of a smartphone-mediated ratiometric chemosensor towards the nanomolar level detection of lethal CN-: combined experimental and theoretical validation with the proposition of a molecular logic circuitry.

A promising naphthalene-functionalized ratiometric chemosensor (E)-1-((naphthalen-5-yl) methylene)-2-(2,4-dinitrophenyl) hydrazine (DNMH) is unveiled in the present work. DNMH demonstrates brisk discernible colorimetric response from yellow to red in the presence of CN-, a lethal environmental contaminant, in a near-perfect aqueous medium with a LOD of 278 nM. The "key role marker" controlling the electrochemical and non-covalent H-bonding interaction between DNMH and CN- is through the commendable role of acidic -NH functionalities. Kinetic studies reveal a pseudo second order reaction rate and the formation of an unprecedented photostable adduct. The negative value of ΔG as evaluated from ITC substantiates the spontaneity of the DNMH⋯CN- interaction. The sensing mechanism was further reinforced with state-of-the-art theoretical investigations, namely DFT, TDDFT and Fukui indices (FIs). Moreover, the proposition of a reversible multi-component logic circuitry implementing Boolean functions in molecular electronics has also been triggered by the turn-over spectrophotometric response of the ditopic ions CN- and Cd2+. The cytotoxicity of DNMH towards Bacillus thuringiensis and Escherichia coli is successfully investigated via the MTT assay. Impressively, "dip stick" and "easy to prepare" test paper device and silica gel-based solid-phase CN- recognition validate the on-site analytical application of DNMH. Furthermore, the involvement of a synergistic approach between 'chemistry beyond the molecule' and 'engineering' via an exquisitely implemented smartphone-assisted colorimetric sensory prototype makes this work unprecedented among its congeners and introduces a new frontier in multitudinous material-based functional product development.

A Ni(II) Metal-Organic Framework with Mixed Carboxylate and Bipyridine Ligands for Ultrafast and Selective Sensing of Explosives and Photoelectrochemical Hydrogen Evolution.

We report a Ni-MOF (nickel metal-organic framework), Ni-SIP-BPY, synthesized by using two linkers 5-sulfoisophthalic acid (SIP) and 4,4'-bipyridine (BPY) simultaneously. It displays an orthorhombic crystal system with the Ama2 space group: a = 31.425 Å, b = 19.524 Å, c = 11.2074 Å, α = 90°, ß = 90°, γ = 90°, and two different types of nickel(II) centers. Interestingly, Ni-SIP-BPY exhibits excellent sensitivity (limit of detection, 87 ppb) and selectivity toward the 2,4,6-trinitrophenol (TNP)-like mutagenic environmental toxin in the pool of its other congeners via "turn-off" fluorescence response by the synergism of resonance energy transfer, photoinduced electron transfer, intermolecular charge transfer, π-π interactions, and competitive absorption processes. Experimental studies along with corroborated theoretical experimentation, vide density functional theory studies, shed light on determining the plausible mechanistic pathway in selective TNP detection, which is highly beneficial in the context of homeland security perspective. Along with the sensing of nitroaromatic explosives, the moderately low band gap and the p-type semiconducting behavior of Ni-SIP-BPY make it suitable as a photoanode material for visible-light-driven water splitting. Highly active surface functionalities and sufficient conduction band minima effectively reduce the water and result in a seven times higher photocurrent density under visible-light illumination.