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.

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.

"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.

Selective recognition of ammonia and aliphatic amines by C-N fused phenazine derivative: A hydrogel based smartphone assisted 'opto-electronic nose' for food spoilage evaluation with potent anti-counterfeiting activity and a potential prostate cancer biomarker sensor.

In real day scenario, it is an urge to provide a single solution of multiple problems. In this regard, herein rapid, selective and highly efficient chromo-fluorogenic detection of ammonia/aliphatic amines over aromatic amines has been investigated by means of a novel "opto-electronic nose", CN-2, synthesized in a single-step via multiple inter/intramolecular C-N fusion reactions. The in-situ generated mono-protonated CN-2 can selectively detect primary to secondary to even tertiary aliphatic amines over aromatic amines within ∼40 S with extremely low detection threshold values of 27.2 ppb, 0.7 ppm, 5.4 ppm, 1.7 ppm from UV-Vis and 42.5 ppb, 1.61 ppm, 5.5 ppm, 6.14 ppm from fluorescence spectral data for NH3, hydrazine (primary amine), diethanolamine (secondary amine) and triethylamine (tertiary amine) respectively with the hypsochromic shift in the UV-Vis spectra along with fluorescence attenuation via target-specific deprotonation. The colorimetric signal can also be examined by Smartphone APP, which is well correlated with spectrophotometric outcomes. Interestingly, due to presence of a unique protonated antenna centre CN-2 with anti-oxidant activity can also detect aliphatic biogenic amines, like putrescine, spermidine, which are frequently released from spoiled food. Therefore, it may be exploited as smart food-spoilage indicator in real-time. Again, the aliphatic biogenic amines recognition capability from human urine made it as a potential prostate cancer biomarker sensor for clinical use, which alleviates the need of biopsies. CN-2 could also be employed towards one-to-two decoder logic-circuitry formulation to monitor the ammonia levels. Moreover, CN-2-functionalized hydrogel-membrane based portable, handy prototype could be utilized for easy on-site recognition of amine vapour. Reversible sensing behaviour in presence of HCl enables CN-2 to exhibit anti-counterfeiting activity. To the best of our knowledge, this is the first all-in-one phenazine-based Smartphone-assisted chromo-fluorogenic-chemosensor, which would be of enormous interest in food-packaging industry, information technology as well as in early-stage-cancer diagnosis.

Knoevenagel condensation triggered synthesis of dual-channel oxene based chemosensor: Discriminative spectrophotometric recognition of F-, CN- and HSO4- with breast cancer cell imaging, real sample analysis and molecular keypad lock applications.

A novel oxene based unusual sensory receptor (HyMa) has been synthesized via.Knoevenagel condensation triggered carbon-heteroatom (oxygen) intramolecular bond formation reaction at room temperature for discriminative detection of multi-analytes like HSO4-, CN- & F- by spectro-photometric alterations with profound selectivity with the detection limit of 38 ppb, 18 ppb & 94 ppb respectively. Examination of the sensing mechanism was exhaustively investigated through several spectroscopic means like 1H NMR, FT-IR, absorption and fluorescence spectra etc. In addition, quantum mechanical calculations like DFT and Loewdin spin population analyses also validated the rationality of the host-guest interaction. Apart from these, the reversible spectroscopic responses of HyMa towards F- and Al3+ can imitate several complex logic functions that in turn help in preparing molecular keypad lock. This molecular keypad lock has the potential to protect the confidential information at the molecular scale. Additionally, the MTT assay of HyMa showed low cytotoxicity and membrane permeability indicating its attractive capability for bio-imaging towards triple negative breast cancer. HyMa-coated test strips could also be employed towards on-site detection of these deadly contaminants via "Dip Stick" approach without help of any instrumentation. In addition, HyMa has also been exploited for quantitative determination of HSO4- from various real water samples. In a nutshell, detection of lethal contaminants like CN-, F- & HSO4- at ppb level with in vitro live cell imaging has been explored with proper photophysical characterisation and theoretical calculations with real field applications.

Amine-substituent induced highly selective and rapid "turn-on" detection of carcinogenic 1,4-dioxane from purely aqueous and vapour phase with novel post-synthetically modified d10-MOFs.

Herein, an amine decorated Cd(II) metal-organic framework (MOF) with a uninodal 6-c topology was synthesized as a suitable platform for facile post-synthetic modification (PSM). The as-synthesized parent d10-MOF (1) with free -NH2 centers, when functionalized with two different carbonyl substituents (1-naphthaldehyde and benzophenone) of varying conjugation, produces two novel luminescent MOFs (LMOFs) viz.PSM-1 and PSM-2. The judicious incorporation of carbonyl substituents into the skeleton of 1 was rationalized via ESI-MS, 1H-NMR, FT-IR and PXRD analyses. Interestingly, both PSM-1 and PSM-2 show 'turn-on' luminescent behaviour in the presence of 1,4-dioxane with the limit of detection (LOD) as 1.079 ppm and 2.487 ppm, respectively, with prompt response time (∼55 s & ∼58 s, respectively). The inhibition of PET is comprehended to be the prime reason for luminescence enhancement upon interaction with the targeted analyte which was further validated from DFT calculations. In continuation, the PSM-MOFs were equally responsive towards 1,4-dioxane in several complex environmental matrices and cosmetic products. Additionally, vapor phase detection of 1,4-dioxane using PSM-MOFs has also been demonstrated as an additional advantage ensuring propagation of future research endeavour.

Trace-Level Humidity Sensing from Commercial Organic Solvents and Food Products by an AIE/ESIPT-Triggered Piezochromic Luminogen and ppb-Level "OFF-ON-OFF" Sensing of Cu2+: A Combined Experimental and Theoretical Outcome.

Selective and sensitive moisture sensors have attracted immense attention due to their ability to monitor the humidity content in industrial solvents, food products, etc., for regulating industrial safety management. Herein, a hydroxy naphthaldehyde-based piezochromic luminogen, namely, 1-{[(2-hydroxyphenyl)imino]methyl}naphthalen-2-ol (NAP-1), has been synthesized and its photophysical and molecular sensing properties have been investigated by means of various spectroscopic tools. Owing to the synergistic effect of both aggregation-induced emission (AIE) and excited-state intramolecular proton transfer (ESIPT) along with the restriction of C=N isomerization, the probe shows bright yellowish-green-colored keto emission with high quantum yield after the interaction with a trace amount of water. This makes NAP-1 a potential sensor for monitoring water content in the industrial solvents with very low detection limits of 0.033, 0.032, 0.034, and 0.033% (v/v) from tetrahydrofuran (THF), acetone, dimethyl sulfoxide (DMSO), and methanol, respectively. The probe could be used in the food industry to detect trace moisture in the raw food samples. The reversible switching behavior of NAP-1 makes it suitable for designing an INHIBIT logic gate with an additional application in inkless writing. In addition, an Internet of Things-(IoT) based prototype device has been proposed for on-site monitoring of the moisture content by a smartphone via Bluetooth or Wi-Fi. The aggregated probe also has the ability to recognize Cu2+ from a purely aqueous medium via the chelation-enhanced quenching (CHEQ) mechanism, leading to ∼84% fluorescence quenching with a Stern-Volmer quenching constant of 1.46 × 104 M-1 and with an appreciably low detection threshold of 57.2 ppb, far below than recommended by the World Health Organization (WHO) and the United States Environmental Protection Agency (U.S. EPA). The spectroscopic and theoretical calculations (density functional theory (DFT), time-dependent DFT (TD-DFT), and natural bond orbital (NBO) analysis) further empower the understanding of the mechanistic course of the interaction of the host-guest recognition event.

Solvothermal Synthesis of High-Performance d10-MOFs with Hydrogel Membranes @ "Turn-On" Monitoring of Formaldehyde in Solution and Vapor Phase.

Herein, two luminescent porous networks (CMERI-1 & CMERI-2) have been reported for the efficient detection of formaldehyde (FA) from aqueous medium. Judicious solvent screening using a high-throughput solvothermal procedure leads to two completely different metal-organic framework (MOFs) with different architectures. It is perceived that the framework CMERI-1 shows better sensitivity with a very short response time (1 min) in the realm of FA detection due to the facile imine (-N═CH-) formation, which is restricted in the case of CMERI-2. The fluorescence "turn-on" behavior is ascribed due to the inhibition of photoinduced electron transfer (PET) (from amine subunit to secondary building unit) process. The detection limits of CMERI-1 & CMERI-2 toward FA in aqueous medium were found to be 0.62 µM (0.019 ppm) and 1.39 µM (0.041 ppm), respectively, that lie far below the intracellular concentration of formaldehyde (100-400 µM). In addition, MOF-based hydrogel membrane was fabricated, which shows vapor-phase detection of FA, which is hitherto unexplored in this realm. Moreover, the response mechanisms of MOFs are supported by density functional theory (DFT) and Fukui indices analysis. The high stability of the porous frameworks along with its interesting sensing features such as fast recognition phenomenon, appreciable detection limit, etc. instigated us to explore its real-world applicability in various food sample and water analyses. In view of the modular design principle of our polymeric probe, the proposed approach could open a new horizon to construct powerful sensing materials for the ultrafast detection of other industrial pollutants in the domain of supramolecular and analytical chemistry.

Exploratory studies on azido-bridged complexes (Ni2+ and Mn2+) as dual colourimetric chemosensors for S2- and Ag+: combined experimental and theoretical outcomes with real field applications.

We report two isostructural dinuclear transition metal complexes [M2(HL)2(N3)4], where M = Ni2+ (BS-1), Mn2+ (BS-2), and HL is (2-methyl-2-((pyridin-2-ylmethyl)amino)propan-1-ol) and investigate them as molecular sensors towards hazardous entities. BS-1 shows high selectivity towards the S2- and Ag+ ions, easily observed by the naked eye colour change and its detection limit in aqueous solutions for the S2- ion was calculated as 0.55 µM with a binding constant of 3.28 × 105 M-1, while the limit for the Ag+ ion is 21.8 µM. Notably, BS-2 shows good selectivity towards the Ag+ ion with a detection limit of 10.84 µM. Spectroscopic and DFT studies shed light on the mechanistic course of interaction between the host and guest entities, suggesting a sulphide-mediated reduction of the azide mechanism. In a nutshell, these simple transition metal complexes were exploited for discriminately detecting hazardous analytes with real field applications in analytical science (via. "Dip-Stick" approach) as well as engineering science, which provides a significant contribution in the recent advancement of supramolecular chemistry.

Discerning Detection of Mutagenic Biopollutant TNP from Water and Soil Samples with Transition Metal-Containing Luminescence Metal-Organic Frameworks.

Two luminescent MOFs, Mn@MOF and Cd@MOF, have been reported herein, which are capable of selectively detecting 2,4,6-trinitrophenol (TNP), one of the potent organic water pollutants in the class of mutagenic explosive nitroaromatic compounds (epNACs). It is perceived that the d10-based Cd(II)-constituting MOF shows a better response in the realm of TNP-like nitroaromatic sensing in comparison to the d5-based Mn@MOF which may possess lower electron density over the conjugated building blocks. The sensing competences of these chemosensors have been explored by means of various spectroscopic experimentations, and it is observed that for both d5 and d10-containing MOFs, the initial fluorescence intensity is significantly quenched in response to an aqueous solution of TNP. However, Cd@MOF is more selective and sensitive toward TNP over several other epNACs than Mn@MOF. The high chemical stability of the MOF samples, as well as its amusing sensing efficiency of Cd@MOF, further instigated to investigate the sensing ability in various environmental specimens like soil and water culled from several zones of West Bengal, India.

Selective Identification and Encapsulation of Biohazardous m-Xylene among a Pool of Its Other Constitutional C8 Alkyl Isomers by Luminescent d10 MOFs: A Combined Theoretical and Experimental Study.

Separation of C8 alkyl-aromatics (o-xylene, m-xylene, and p-xylene) remains one of the most challenging tasks to date due to their similar physical and chemical properties. Cd2+- and Zn2+-based luminescent metal-organic frameworks (MOFs) have been synthesized for the selective identification of m-xylene in a pool of other isomers by fluorometric methods. Inhibition of the photoinduced electron transfer process is the prime reason for fluorescence enhancement, owing to the comparable molecular orbital energies for m-xylene in comparison with o- and p-xylene. Density functional theory calculations signify that the extraordinary selectivity is mainly due to the high dipole moment of m-xylene that might enhance the ring current, leading to a strong π-π interaction with the MOF's co-ligand. As a practical application, fluorometric sensing could be used for the estimation of m-xylene in different solvent media. Moreover, X-ray structural analysis reveals that the Zn2+-MOF can encapsulate m-xylene selectively within its framework among other constitutional isomers, which also emphasizes its capability for practical implementation.