Fabrication of Unique Mixed-Valent CoICoII and CuICuII Metal-Organic Frameworks (MOFs) for Desulfurization of Fuels: A Combined Experimental and Theoretical Approach toward Green Fuel.

Herein, metal-organic framework (MOF)-based adsorbents are designed with distinct hard and soft metal building units, namely, [Co2ICoII(PD)2(BP)] (Co_PD-BP) and [Cu2ICuII(PD)2(BP)] (Cu_PD-BP), where H2PD = pyrazine-1,4-diide-2,3-dicarboxylic acid and BP = 4,4'-bipyridine. The designed MOFs were characterized via spectral and SCXRD techniques, which confirm the mixed-valent states (+1 and +2) of the metal ions. Topological analysis revealed the rare ths and gwg topologies for Co MOF, while Cu-MOF exhibits a unique 8T21 topology in the 8-c net (point symbol for net: {424·64}). Moreover, severe environmental issues can be resolved by effectively removing heterocyclic organosulfur compounds from fuels via adsorptive desulfurization. Further, the developed MOFs were investigated for sulfur removal via adsorptive desulfurization from a model fuel consisting of dibenzothiophene (DBT), benzothiophene (BT), and thiophene (T) in the liquid phase using n-octane as a solvent. The findings revealed that Cu_PD-BP effectively removes the DBT with a removal efficiency of 86% at 300 ppm and an operating temperature of 25 °C, with a recyclability of up to four cycles. The adsorption kinetic analysis showed that the pseudo-first-order model could fit better with the experimental data indicating the physisorption process. Further, the studies revealed that adsorption capacity increased with the increasing initial DBT concentration with a remarkable capacity of 70.5 mg/g, and the adsorption process was well described by the Langmuir isotherm. The plausible reason behind the enhanced removal efficiency shown by Cu_PD-BP as compared to Co_PD-BP could be the soft-soft interactions between soft sulfur and soft Cu metal centers. Interestingly, density functional theory (DFT) studies were done in order to predict the mechanism of binding of thiophenic compounds with Cu_PD-BP, which further ascertained that along with other interactions, the S···π and S···Cu interactions predominate, resulting in a high uptake of DBT as compared to others. In essence, Cu_PD-BP turns out to be a promising adsorbent in the field of fuel desulfurization for the benefit of mankind.

Studying the Symphonizing Effect of NLO Properties in Hydrated and Non-hydrated Donor Acceptor Complexes Formed Via Charge Transfer.

The present work intended to report the synthesis of newly designed donor-acceptor complexes of the pyrimidine-based system namely TAPHIA 1 and TAPHIA 2, which are symphonized to give the NLO properties. The methodologies adopted for both complexes were different and hence influenced their geometrical properties. The synthesized complexes were characterized using different techniques including SCXRD, FTIR, UV, PXRD, and TGA to confirm their formation. The SCXRD analysis revealed that TAPHIA 1 was crystallized in the Pca21 space group in an orthorhombic system while TAPHIA 2 was crystallized in the P21/c space group in a monoclinic system. The third-order NLO properties of both complexes were explored using the Z-Scan technique by employing a continuous wave (CW) diode laser of 520 nm. The third-order NLO parameters including nonlinear refractive index (n2), nonlinear absorption coefficient (ß) and nonlinear optical susceptibility (χ (3)) were calculated at different powers; 40, 50 and 60 mW at fixed solution concentration (10 mM) for both the complexes. Moreover, the experimental properties including NLO, FTIR, and UV were well corroborated with theoretical results obtained at the B3LYP-D3/6-31++G(d,p) level of theory. The analysis of the theoretical and experimental properties of both complexes suggests that TAPHIA 2 is a better applicant to be employed in optical devices than TAPHIA 1 due to the enhanced ability of internal charge transfer.

AuCFSR: Authentication and Color Face Self-Recovery Using Novel 2D Hyperchaotic System and Deep Learning Models.

Color face images are often transmitted over public channels, where they are vulnerable to tampering attacks. To address this problem, the present paper introduces a novel scheme called Authentication and Color Face Self-Recovery (AuCFSR) for ensuring the authenticity of color face images and recovering the tampered areas in these images. AuCFSR uses a new two-dimensional hyperchaotic system called two-dimensional modular sine-cosine map (2D MSCM) to embed authentication and recovery data into the least significant bits of color image pixels. This produces high-quality output images with high security level. When tampered color face image is detected, AuCFSR executes two deep learning models: the CodeFormer model to enhance the visual quality of the recovered color face image and the DeOldify model to improve the colorization of this image. Experimental results demonstrate that AuCFSR outperforms recent similar schemes in tamper detection accuracy, security level, and visual quality of the recovered images.

Crystal Structure, Topology, DFT and Hirshfeld Surface Analysis of a Novel Charge Transfer Complex (L3) of Anthraquinone and 4-{[(anthracen-9-yl)meth-yl] amino}-benzoic Acid (L2) Exhibiting Photocatalytic Properties: An Experimental and Theoretical Approach.

Here, we report a facile route to the synthesizing of a new donor-acceptor complex, L3, using 4-{[(anthracen-9-yl)meth-yl] amino}-benzoic acid, L2, as donor moiety with anthraquinone as an acceptor moiety. The formation of donor-acceptor complex L3 was facilitated via H-bonding and characterized by single-crystal X-ray diffraction. The X-ray diffraction results confirmed the synthesized donor-acceptor complex L3 crystal belongs to the triclinic system possessing the P-1 space group. The complex L3 was also characterized by other spectral techniques, viz., FTIR and UV absorption spectroscopy, which confirmed the formation of new bonds between donor L2 moiety and acceptor anthraquinone molecule. The crystallinity and thermal stability of the newly synthesized complex L3 was confirmed by powdered XRD and TGA analysis and theoretical studies; Hirshfeld surface analysis was performed to define the type of interactions occurring in the complex L3. Interestingly, theoretical results were successfully corroborated with experimental results of FTIR and UV absorption. The density functional theory (DFT) calculations were employed for HOMO to LUMO; the energy gap (∆E) was calculated to be 3.6463 eV. The complex L3 was employed as a photocatalyst for the degradation of MB dye and was found to be quite efficient. The results showed MB dye degraded about 90% in 200 min and followed the pseudo-first-order kinetic with rate constant k = 0.0111 min-1 and R2 = 0.9596. Additionally, molecular docking reveals that the lowest binding energy was -10.8 Kcal/mol which indicates that the L3 complex may be further studied for its biological applications.

Molecular designing, crystal structure determination and in silico screening of copper(II) complexes bearing 8-hydroxyquinoline derivatives as anti-COVID-19.

The pandemic by COVID-19 is hampering everything on the earth including physical and mental health, daily life and global economy. At the moment, there are no defined drugs, while few vaccines are available in the market to combat SARS-CoV-2. Several organic molecules were designed and tested against the virus but they did not show promising activity. In this work we designed two copper complexes from the ligands analogues with chloroquine and hydroxychloroquine. Both the ligands and complexes were well characterized by using various spectroscopic, thermal and X-ray diffraction techniques. Both the complexes as well as ligands were screened through in silico method with the chloroquine and hydroxychloroquine which essentially proved pivotal for successful understanding towards the target protein and their mechanism of action. The results indicated that the balanced hydrophobic and polar groups in the complexes favor their binding in the active site of the viral ADP-ribose-1 monophosphatase enzyme over the parent organic molecules.

Evaluation of catacholase mimicking activity and apoptosis in human colorectal carcinoma cell line by activating mitochondrial pathway of copper(II) complex coupled with 2-(quinolin-8-yloxy)(methyl)benzonitrile and 8-hydroxyquinoline.

To evaluate the cytotoxic potential of metal-based chemotherapeutic candidate towards the colorectal cancer, we have synthesized a new copper(II) complex [Cu(qmbn)(q)(Cl)] (1) (where, qmbn = 2-(quinolin-8-yloxy)(methyl)benzonitrile and q = 8-hydroxyquinoline) and structurally characterized by single crystal X-ray, Powder-XRD, FTIR and thermogravimetric analysis (TGA). The structural analysis reveals that copper(II) ions exist in a distorted square pyramidal (τ = ~0.1), with ligation of a chloride ion, oxygen atom and two nitrogen atoms at equatorial position and one oxygen atom at apical position. The cytotoxicity potential of complex 1 was executed against human colorectal cell lines (HCT116), which showed that 1 induces mitochondrion-mediated apoptotic cell death via activation of the Bax (pro-apoptotic protein) caspases-3 and 9 proteins. Interestingly, complex 1 was found to be a good candidate as electron-transfer catalyst which mimics catacholase with high turnover frequency (kcat = 1.03 × 102 h-1) for the conversion of the model substrate 3,5-di-tertbutylcatechol (3,5-DTBC) to 3,5-di-tertbutylquinone (3,5-DTBQ). Furthermore, molecular docking studies revealed that complex 1 was successfully localized inside the binding pocket of protein kinase (Akt), which validate the mechanism and mode of interaction of 1 that displayed cytotoxic activity experimentally. The obtained outcomes reveal that the complex 1 could be utilized as an encouraging perspective in the development of new therapeutic candidate for colon cancer.

Anticancer properties, apoptosis and catecholase mimic activities of dinuclear cobalt(II) and copper(II) Schiff base complexes.

The present work describes coordination chemistry and biological evaluation of two novel dinuclear complexes [Co2(HL1)2(H2O)2]·8H2O (1) and [Cu2(L2)2] (2) obtained from the Schiff base ligands, H3L1 and H2L2 (formed in situ). The two complexes are characterized by single crystal X-ray, spectral and variable temperature magnetic and theoretical (DFT/TDDFT) analysis. X-ray analysis confirms both the complexes to be dinuclear with distorted octahedral and square pyramidal geometry around Co(II) and Cu(II) ions, respectively. Magnetic studies reveal presence of moderate ferromagnetic interactions in both the complexes with J = 98 (1) and 32 (2) cm-1. The magnetic interactions are further corroborated by DFT studies. Co(II) complex (1) exhibited enhanced catecholase activity with Kcat = 213.48 h-1, which is attributed to the greater extent of charge contribution on Co2+ as compared to Cu2+ as determined by DFT calculations. Furthermore, both the complexes show potent anticancer activity toward HeLa (cervical) and A549 (lung) cancer cell lines with IC50 = 6-7 µM at 48 h, which ascertains both the complexes as better anticancer drugs than cisplatin. Furthermore, 1 and 2 exhibit apoptosis of HeLa cells by demonstrating nuclear blebbings with shrinking morphology. Hence, the present complexes could be employed as a model for metalloenzymes as well as potential anticancer substituents of cisplatin in future course.

Evolving Dynamic S-Boxes Using Fractional-Order Hopfield Neural Network Based Scheme.

Static substitution-boxes in fixed structured block ciphers may make the system vulnerable to cryptanalysis. However, key-dependent dynamic substitution-boxes (S-boxes) assume to improve the security and robustness of the whole cryptosystem. This paper proposes to present the construction of key-dependent dynamic S-boxes having high nonlinearity. The proposed scheme involves the evolution of initially generated S-box for improved nonlinearity based on the fractional-order time-delayed Hopfield neural network. The cryptographic performance of the evolved S-box is assessed by using standard security parameters, including nonlinearity, strict avalanche criterion, bits independence criterion, differential uniformity, linear approximation probability, etc. The proposed scheme is able to evolve an S-box having mean nonlinearity of 111.25, strict avalanche criteria value of 0.5007, and differential uniformity of 10. The performance assessments demonstrate that the proposed scheme and S-box have excellent features, and are thus capable of offering high nonlinearity in the cryptosystem. The comparison analysis further confirms the improved security features of anticipated scheme and S-box, as compared to many existing chaos-based and other S-boxes.

A Novel Construction of Efficient Substitution-Boxes Using Cubic Fractional Transformation.

A symmetric block cipher employing a substitution-permutation duo is an effective technique for the provision of information security. For substitution, modern block ciphers use one or more substitution boxes (S-Boxes). Certain criteria and design principles are fulfilled and followed for the construction of a good S-Box. In this paper, an innovative technique to construct substitution-boxes using our cubic fractional transformation (CFT) is presented. The cryptographic strength of the proposed S-box is critically evaluated against the state of the art performance criteria of strong S-boxes, including bijection, nonlinearity, bit independence criterion, strict avalanche effect, and linear and differential approximation probabilities. The performance results of the proposed S-Box are compared with recently investigated S-Boxes to prove its cryptographic strength. The simulation and comparison analyses validate that the proposed S-Box construction method has adequate efficacy to generate efficient candidate S-Boxes for usage in block ciphers.

An Efficient Mutual Authentication Framework for Healthcare System in Cloud Computing.

The increasing role of Telecare Medicine Information Systems (TMIS) makes its accessibility for patients to explore medical treatment, accumulate and approach medical data through internet connectivity. Security and privacy preservation is necessary for medical data of the patient in TMIS because of the very perceptive purpose. Recently, Mohit et al.'s proposed a mutual authentication protocol for TMIS in the cloud computing environment. In this work, we reviewed their protocol and found that it is not secure against stolen verifier attack, many logged in patient attack, patient anonymity, impersonation attack, and fails to protect session key. For enhancement of security level, we proposed a new mutual authentication protocol for the similar environment. The presented framework is also more capable in terms of computation cost. In addition, the security evaluation of the protocol protects resilience of all possible security attributes, and we also explored formal security evaluation based on random oracle model. The performance of the proposed protocol is much better in comparison to the existing protocol.

A New Hyperchaotic System-Based Design for Efficient Bijective Substitution-Boxes.

In this paper, we present a novel method to construct cryptographically strong bijective substitution-boxes based on the complicated dynamics of a new hyperchaotic system. The new hyperchaotic system was found to have good characteristics when compared with other systems utilized for S-box construction. The performance assessment of the proposed S-box method was carried out based on criteria, such as high nonlinearity, a good avalanche effect, bit-independent criteria, and low differential uniformity. The proposed method was also analyzed for the batch-generation of 8 × 8 S-boxes. The analyses found that through a proposed purely chaos-based method, an 8 × 8 S-box with a maximum average high nonlinearity of 108.5, or S-boxes with differential uniformity as low as 8, can be retrieved. Moreover, small-sized S-boxes with high nonlinearity and low differential uniformity are also obtainable. A performance comparison of the anticipated method with recent S-box proposals proved its dominance and effectiveness for a strong bijective S-box construction.

N (1)-[(1H-Imidazol-2-yl)methyl-idene]-N (4)-phenyl-benzene-1,4-di-amine.

The title compound, C16H14N4, is non-planar with dihedral angles between the planes of the imidazole and phenyl-enedi-amine rings of 30.66 (4)° and between the planes of the phenyl-enedi-amine and N-phenyl rings of 56.63 (7)°. In the crystal, mol-ecules are connected by N-H⋯N hydrogen bonds, generating a chain extending along the b-axis direction. The crystal structure is also stabilized by C-H⋯π inter-actions between N-phenyl and imidazole rings and slipped π-π stacking inter-actions between imidazole rings [centroid-centroid distance = 3.516 (4) Å] giving an overall two-dimensional layered structure lying parallel to (010).

Ratiometric luminescent sensing of a biomarker for sugar consumption in an aqueous medium using a Cu(II) coordination polymer.

An innovative [Cu(Hadp)2(Bimb)]n (KA@CP-S3) coordination polymer expands its dimensionality from a 1D chain to a 2D network. The topological analysis reveals that KA@CP-S3 has 2-connected uninodal 2D 2C1 topology. KA@CP-S3 has capable luminescent sensing for volatile organic compounds (VOCs), nitroaromatics, heavy metal ions, anions, disposed antibiotics (nitrofurantoin and tetracycline) and biomarkers. Intriguingly, KA@CP-S3 exhibits outstanding selective quenching of about 90.7% and 90.5% for the 125 mg dl-1 and 150 mg dl-1 strengths of sucrose, respectively, in aqueous solution along with other ranges in between. The photocatalytic degradation efficiency of KA@CP-S3 for the potentially harmful organic dye Bromophenol Blue displays 95.4%, which is the highest among the 13 dyes that were evaluated.

Structural, Theoretical Investigations, Hirshfeld Surface Analysis, and Cytotoxicity Profile of a Neocuproine-Co(II)-Based Discrete Homodinuclear Complex.

In this work, we aimed to synthesize a new cobalt(II) complex, namely [Co2(µ-HIPA)(NC)2(H2O)3(NO3)]·(NO3)(C2H5OH)(1) (where H3IPA = 5-hydroxy isophthalic acid and NC = 2,9-dimethyl-1,10-phenanthroline or neocuproine), as a promising chemotherapeutic agent. The diffraction (single crystal-XRD and powder-XRD), spectroscopic (FTIR and UV-visible), molar conductance, and thermal techniques were used to characterize complex 1. Single-crystal X-ray diffraction analysis reveals that Co(II) exists in an octahedral geometry, with the ligation of four oxygen atoms, and two nitrogen atoms. Topological analysis of complex 1 reveals 2,6C6 topological type as an underlying net. The plausible intermolecular interactions within complex 1 that control the crystal packing were analyzed by Hirshfeld surface analysis. In vitro cytotoxicity of complex 1 was evaluated against acute myeloid leukemia (THP-1), colorectal (SW480), and prostate (PC-3) cancer cell lines by utilizing an MTT assay. The result shows that complex 1 can inhibit the growth of cancer cells (THP-1, SW480, and PC-3) at lower inhibitory concentration (IC50) values of > 100, 43.6, and 95.1 µM respectively. The morphological changes induced by complex 1 on THP-1 and SW480 cancer cell lines were carried out with acridine orange/ethidium bromide staining methods. Additionally, comprehensive molecular docking studies were performed to understand the potential binding interactions of complex 1 with different bio-macromolecules.

A bifunctionalised Pb-based MOF for iodine capture and dye removal.

A 2-dimensional Pb(II) metal-organic framework, [Pb(bdc)0.5(py-Phen)NO3]n (SM-3), was synthesized under solvothermal conditions using a mixed ligand approach. SM-3 was assembled using dinuclear SBUs [Pb2(COO)2]2-, an oxygen donor H2bdc = 1,4-benzene dicarboxylic acid, and nitrogen donor py-Phen = pyrazino[2,3-f][1,10]-phenanthroline linkers. SM-3 was characterized by elemental analysis, FT-IR, powder-X-ray diffraction, thermal gravimetric analysis, SEM, EDS, TEM, and single-crystal X-ray diffraction techniques. Crystallographic studies confirmed that SM-3 displays a 2D layered structure with unique anagostic (Pb⋯H) interactions. Interestingly, the presence of abundant π-electron-rich rings embellished with free -N donor sites in the framework makes SM-3 an excellent adsorbent that exhibits adsorption performance for iodine and dyes. The experimental results show that SM-3 reversibly adsorbs radioactive iodine in the solution and vapor phases and exhibits selective adsorption performance for hazardous cationic dyes, namely, methylene blue (MB) and rhodamine-B (Rh-B), from aqueous solution. Moreover, the possible mechanism of iodine and dye adsorption was also discussed in detail. Thus, this work is remarkable for coordination chemists to engineer layered MOFs for adsorption purposes and expands their potential characteristics by converting them into 2D MOF nanosheets to further enhance the adsorption of hazardous pollutants for environment protection.

Suppression of human lysozyme aggregation by a novel copper-based complex of 3,4-dimethoxycinnamic acid.

In this work, a new Cu(II)-based complex as a chemotherapeutic drug agent, formulated as[Cu(DCA)4(H2O)2]⋅4H2O⋅4MeOH, (DCA = 3,4-dimethoxycinnamic acid), namely 1 was successfully synthesized utilizing DCA as a ligand to arrest fibrillation in Human lysozyme. The 1 was thoroughly characterized by single crystal X-ray diffraction (SC-XRD), spectroscopic (UV-Vis and FTIR) techniques, PXRD, and TGA analysis. Its crystal structure reveals a paddle wheel network around central copper metal ions. The Cu(II) metal ions exhibit a distorted square pyramidal configuration. The fluorescence titration studies showed moderate binding interaction of 1 with HuL with Ka of 6.3x105 M-1 at pH-2, 25 °C due to its interaction withAsp53, Tyr63, Val110, and Ala111 as shown by docking and simulation studies. 1suppresses the HuL fibrillation in a concentration-dependent manner, as demonstrated by ThT assay. At 200 µM concentration, it leads to the formation of smaller species of the protein in comparison to the control sample, as suggested by Light Scattering studies. The species formed are less hydrophobic and retain their native α-helix structure compared to the control samples, which are hydrophobic and form ß-sheet rich amyloids as shown by ANS hydrophobicity assay and CD spectroscopy, respectively. Furthermore, morphological analysis of the species by AFM has demonstrated that, unlike mature amyloid fibrils in the control sample, HuL forms small-size aggregates in the presence of 1 under similar fibrillation conditions. It can be concluded that 1 effectively suppresses HuL fibrillation due to moderate binding to the protein.Communicated by Ramaswamy H. Sarma.

Secure communication through reliable S-box design: A proposed approach using coset graphs and matrix operations.

Protection of sensitive information has been always the major security concern since decades to withstand against illegitimate access and usage. Substitution-boxes (S-boxes) are vital components of any modern day cryptographic system that allows us to ensure its resistance to attacks. The prime problem with creating S-box is that we are generally unable to discover a consistent distribution among its numerous features to withstand diverse cryptanalysis attacks. The majority of S-boxes investigated in the literature has good cryptographic defenses against some attacks but are susceptible to others. Keeping these considerations in mind, this paper proposes a novel approach for S-box design based on a pair of coset graphs and a newly defined operation of row and column vectors on a square matrix. Several standard performance assessment criteria are used to evaluate the reliability of proposed approach, and the results demonstrate that the developed S-box satisfies all criterions for being robust for secure communication and encryption.

Bifunctional Cu(II)-based 2D coordination polymer and its composite for high-performance photocatalysis and electrochemical energy storage.

Coordination polymers (CPs) have been widely proven as sacrificial electrode materials for energy storage applications because of their high porosity, specific surface area and tunable structural topology. In this work, a new 2D Cu(II)-based CP, formulated as [Cu2(btc)(µ-Cl)2(H2O)4]n (CP-1) (H3btc = benzene-1,3,5-tricarboxylic acid), fabrication of copper oxide nanoparticles (CuO NPs) and its composite (CuO@CP-1) were successfully synthesized using solvothermal, precipitation and mechanochemical grinding approaches. Single-crystal X-ray analysis authenticated a two-dimensional (2D) layered network of CP-1. Further, CP-1, CuO NPs and composite were characterized by diffraction (Powder-XRD), spectroscopic (FTIR), microscopic (SEM), and thermal (TGA) techniques. The porosity and surface behavior of CP-1 and the composite were demonstrated using BET analyzer. Topological simplification of CP-1 shows a 3-c connected hcb periodic net. The photocatalytic behavior of CP-1 was examined over methyl red (MR) dye in the presence of sunlight and showed a promising degradation efficiency of 96.80%. The electrochemical energy storage properties of CP-1, CuO NPs and composite were investigated using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) analysis under aqueous 1 M H2SO4 electrolyte. The electrochemical results show better charge storage performance of CP-1 with a specific capacitance of 602.25 F g-1 at 1 A g-1 current density by maintaining a retention of up to 84.51% after 5000 cycles at 10 A g-1 current density. Comparative electrochemical studies reveal that CP-1 is a promising electrode material for energy storage.

Carbon Nanotubes Decorated with Coordination Polymers for Fluorescence Detection of Heavy-Metal Ions and Nitroaromatic Chemicals.

Herein, [Nd(NO3)3(H2pzdca)] n (MA-1) was synthesized from a reaction of 2,3-pyrazinedicarboxylic acid [H2Pzdca] as an organic linker with salt of Nd(III) under solvothermal conditions. The detailed structural analysis for crystals was performed utilizing single-crystal X-ray diffraction (SCXRD). After that, the neodymium-based coordination polymer (MA-1) crystal was directly generated upon the surface of functionalized carbon nanotubes (F-CNTs) through bonds or affinity between F-CNTs and MA-1 via the solvothermal approach. Meanwhile, the existence of F-CNTs does not affect the production of MA-1 crystals. FT-IR, PXRD, SEM, TEM, and SCXRD studies were used to characterize the crystalline material, MA-1 and MA-1@CNT. To investigate the MA-1@CNT sensing properties, Pb(II), As(III), Cr(VI), and nitrobenzene (NB) were utilized as analytes. It is worth mentioning that MA-1@CNT developed as a susceptible sensor exhibits a fluorescence "turn-on" response for Pb(II) and As(III) ions, while a fluorescence "turn-off" response in the case of Cr(VI) and NB with significantly low limit of detection (LOD) values of 15.9 for Pb(II), 16.0 for As(III), 76.9 for Cr(VI), and 21.1 nM for NB, which are comparable with the lowest LOD available in the literature. Furthermore, MA-1@CNT could be conveniently regenerated and reused for at least three cycles by simply filtering and washing with water several times. The sensing mechanism is ascribed to the inner filter effect owing to the overlap between the emission and/or excitation bands of MA-1@CNT with the absorption bands of Cr(VI) and NB. In contrast, the fluorescence enhancement in the case of Pb(II) and As(III) could be correlated to the chelation-enhanced fluorescence phenomenon. These results indicate that MA-1@CNT is an ideal sensor for Pb(II), As(III), Cr(VI), and NB recognition.

Synthesis of 2D Metal-Organic Nanosheets (MONs) by Liquid Phase Exfoliation: Applications in Effective Delivery of Antiulcer Drugs and Selective Adsorption and Removal of Cationic Dyes.

Nowadays, the fabrication of 2D metal-organic nanosheets (2D MONs) has entered the research arena fascinating researchers worldwide. However, a lack of efficient and facile methods has remained a bottleneck for the manufacturing of these 2D MONs. Herein, a 2D metal-organic framework (MOF), i.e., 2D Cu-MOF, was synthesized using a facile and convenient stirring method by using 4,4'-trimethylenedipyridine (TMDP) as an organic linker. The as-prepared MOF was characterized in detail and based on single crystal X-ray diffraction analysis, it was established that tangled layers in the 2D Cu-MOF are interconnected to produce thick strands. These tangled layers could be easily separated via ultrasonication-induced liquid phase exfoliation (UILPE) to give the 2D Cu-MON as illustrated through Tyndall light scattering and exhaustive microscopic exploration such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The application of this 2D Cu-MON was assessed in the field of drug delivery revealing exceptional drug loading for the drug lansoprazole (LPZ) by 2D Cu-MONs as well as drug release in the acidic and neutral medium demonstrating that the 2D Cu-MON is an excellent carrier for antiulcer drug delivery. For environmental protection, the application of 2D Cu-MON was also examined toward the removal of various cationic and anionic dyes with excellent selectivity toward cationic dye removal. The plausible mechanism for dye removal indicated the involvement of cation-π and π-π interactions, for the effective adsorption of cationic dyes as well as a increase in the surface area of 2D Cu-MON by UILPE. Remarkably, the high drug loading and dye removal are imputed to the increase in surface area by UILPE. In a nutshell, the developed 2D Cu-MON will prove to be beneficial for application in the field of drug delivery as well as for wastewater treatment.