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.

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.

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.

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.

A 3D copper (II) coordination polymer based on sulfanilic acid ligand (CP 1) for efficient biomolecular interaction with bovine serum albumin: spectroscopic, molecular modelling and DFT analysis.

Several biochemical reactions occur during the interaction of metal complexes and proteins due to conformational modifications in the structure of the protein, which provide fundamental knowledge of the effect, mechanism, and transport of many drugs throughout the body. Here, we report the synthesis, identification, and impact of the 3-dimensional Copper(II)sulfanilic acid coordination polymer (CP 1) on interactions with bovine serum albumin (BSA). The CP 1 was synthesized via a simple hot stirring method, and the single crystal XRD confirms the effective bonding interactions between metal and organic ligand, forming a crystalline polymeric chain and the topological study shows the sql type of underlying net topology. Powder XRD, Fourier transform infrared spectroscopy, and thermogravimetric analysis were also performed. Moreover, DFT/B3LYP calculations provide chemical precision for the resulting complex. Further, the changes that occur in the secondary structure of protein when CP 1 binds with BSA as well as its binding capacity were investigated via circular dichroism analysis and spectroscopic methods such as UV-absorption spectroscopy and fluorescence spectroscopy, respectively. The CP 1/BSA complex melting point was also measured, and its temperature-dependent heat denaturation was studied along with molecular docking.Communicated by Ramaswamy H. Sarma.

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.

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.

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.

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.

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.

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.

Dual-Ligand Strategy Employing Rigid 2,5-Thiophenedicarboxylate and 1,10-Phenanthroline as Coligands for Solvothermal Synthesis of Eight Lanthanide(III) Coordination Polymers: Structural Diversity, DFT Study, and Exploration of the Luminescent Tb(III) Coordination Polymer as an Efficient Chemical Sensor for Nitroaromatic Compounds.

Lanthanide coordination polymers (Ln-CPs) are potential chemosensors when fabricated to depict a detectable change in optical properties on interaction with target analytes. This work investigates the interaction of nitroaromatic compounds with Ln-CPs leading to induced changes in fluorescence emission intensity, a crucial strategy to develop a selective and sensitive system for the sensing of nitroaromatics. Approaching toward this objective, solvothermal reactions of 2,5-thiophenedicarboxylic (2,5-TDC) acid, 1,10-phenanthroline (1,10-Phen), and Ln(NO3)3·xH2O are carried out to assemble eight Ln(III) coordination polymers [Ln2(2,5-TDC)3(1,10-Phen)2(H2O)2] [Ln = Pr (1), Nd (2)], {[Tb(2,5-TDC)1.5(1,10-Phen)(H2O)]·DMF} (3), and [Ln(2,5-TDC)1.5(1,10-Phen)]·xH2O (Ln = Tb (4), Dy (5), Ho (6), Er (7), and Yb (8)); x = 0 for CP 4, 5, 6, and 8 and x = 1 for CP 7 with two different space groups and dimensions. The as-synthesized polymers 1-8 are characterized by powder X-ray crystallography, infrared spectroscopy, and thermogravimetric analysis. The structure-corroborated density functional theory (DFT) studies are done on the selected CPs to investigate the interactions between different structural motifs of the assembled CPs. The luminescence properties of CP 4 are explored in detail and are found to be highly sensitive for the detection of p-nitrotoluene as indicated by the most intensive fluorescence quenching with the lowest limit of detection (0.88 ppm) and high quenching constant (4.3 × 104 M-1). Other nitro compounds (viz., o-nitrobenzaldehyde, m-nitroaniline, picric acid, m-dinitrobenzene, p-nitrophenol, and p-nitroaniline) are also screened for potential sensing by CP 4.

Synthesis of a Mixed-Ligand H-Bonded Cu Coordination Polymer: Exploring the pH-Dependent High Photocatalytic Degradation of Rhodamine 6G, Methyl Violet, Crystal Violet, and Rose Bengal Dyes under Room Illumination.

A new mixed-ligand H-bonded coordination polymer {[Cu2(Or)2(Bimb)3]·4H2O} n (KA@CP-S) has been prepared hydrothermally using basic copper carbonate with 1,4-bis[(1H-imidazol-1-yl)methyl]benzene (Bimb) and potassium orotate (OrK) ligands. According to topological studies, KA@CP-S has a new topology with a three-connected uninodal net with point symbol (PS) {82·12}2{8}3. The KA@CP-S was employed as a catalyst for screening of a series of harmful cationic, anionic, and neutral organic dyes in contaminated water. The photocatalytic degradation study shows that it exhibits good catalytic efficiency for cationic dyes like Crystal Violet (CV, 75.8%), Methyl Violet (MV, 76.8%), and Rhodamine 6G (Rh6G, 86.5%) and Rose Bengal (RB, 76.1%), which is an anionic dye, while for a neutral dye, its catalytic efficiency is only 72% (Neutral Red) at ambient temperature. The effect of pH on photocatalytic degradation was also analyzed. The degradation experiment reveals that the detection limits of KA@CP-S for mostly catalyzed colorant concentrations in contaminated water are 0.60 ppm (CV), 0.20 ppm (RB), 0.33 ppm (MV), and 0.20 ppm (Rh6G) at pH 12, 4, and 10. The degradation of dyes follows pseudo-first-order kinetics. The excellent catalytic property and regeneration ability of KA@CP-S make it a potential and efficient future remedial material for the detection and separation of toxic dyes from wastewater contaminated by industrial effluents.

Crystal structure and Hirshfeld surface analysis of 2,4,6-tri-amino-pyrimidine-1,3-diium dinitrate.

The title compound, C4H9N5 2+·2NO3 -, crystallizes in the monoclinic crystal system, space group P21/c. The asymmetric unit, which comprises a diprotonated tri-amino-pyrimidine dication and two nitrate anions, has an almost planar geometry with a dihedral angle of 0.92 (4)° between the mean plane of the cation and that defined by both anions. In the crystal, hydrogen-bonding inter-actions between the 2,4,6-tri-amino-pyrimidine cation and the nitrate anions lead to a one-dimensional supra-molecular network with weak anionic inter-actions forming a three-dimensional network. These inter-actions were investigated using Hirshfeld surface analysis, which indicates that the most important contributions for the packing arrangement are from O⋯H/H⋯O (53.2%), N⋯H/H⋯N (12.5%) and C⋯H/H⋯C (9.6%) inter-actions. Energy framework analysis showed that of the components of the framework energies, electrostatic repulsion (E rep) is dominant.

Construction of a 3D Metal-Organic Framework and Its Composite for Water Remediation via Selective Adsorption and Photocatalytic Degradation of Hazardous Dye.

In this work, a new bimetallic Na(I)-Zn(II) metal-organic framework (MOF), formulated as [Na2Zn3(btc)2(µ-HCOO)2(µ-H2O)8] n (1) (H3btc = benzene tricarboxylic acid), and its composite (ZnO@1) have been successfully synthesized using solvothermal and mechanochemical solid grinding methods. 1 and ZnO@1 were characterized by diffraction [single-crystal X-ray diffraction (XRD) and powder XRD], spectroscopic (ultraviolet-visible diffuse reflectance spectroscopy and Fourier transform infrared spectroscopy), microscopic (transmission electron microscopy), and thermal (thermogravimetric analysis) methods. The surface area and porosity of 1 were determined using a Brunauer-Emmett-Teller analyzer. Single-crystal diffraction of 1 confirms that Na1 and Zn2 have octahedral coordination environments, whereas Zn1 has a tetrahedral coordination geometry. Topological simplification of 1 shows a 3,6-connected kgd net. Na(I)-Zn(II) MOF (1) is crystallized with slight porosity and exhibits good tendency toward the encapsulation of zinc oxide nanoparticles (ZnO NPs). The photocatalytic behaviors of 1 and its composite (ZnO@1) were investigated over MB dye under sunlight illumination with promising degradation efficiencies of 93.69% for 1 and 97.53% for ZnO@1 in 80 min.

RAPCHI: Robust authentication protocol for IoMT-based cloud-healthcare infrastructure.

With the fast growth of technologies like cloud computing, big data, the Internet of Things, artificial intelligence, and cyber-physical systems, the demand for data security and privacy in communication networks is growing by the day. Patient and doctor connect securely through the Internet utilizing the Internet of medical devices in cloud-healthcare infrastructure (CHI). In addition, the doctor offers to patients online treatment. Unfortunately, hackers are gaining access to data at an alarming pace. In 2019, 41.4 million times, healthcare systems were compromised by attackers. In this context, we provide a secure and lightweight authentication scheme (RAPCHI) for CHI employing Internet of medical Things (IoMT) during pandemic based on cryptographic primitives. The suggested framework is more secure than existing frameworks and is resistant to a wide range of security threats. The paper also explains the random oracle model (ROM) and uses two alternative approaches to validate the formal security analysis of RAPCHI. Further, the paper shows that RAPCHI is safe against man-in-the-middle and reply attacks using the simulation programme AVISPA. In addition, the paper compares RAPCHI to related frameworks and discovers that it is relatively light in terms of computation and communication. These findings demonstrate that the proposed paradigm is suitable for use in real-world scenarios.

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.

The cocrystal of 3-((4-(3-isocyanobenzyl) piperazine-1-yl) methyl) benzonitrile with 5-hydroxy isophthalic acid prevents protofibril formation of serum albumin.

The formation of amyloid-like fibrils is a central problem in biophysical chemistry and medicine. Fibril formation and their deposition in various tissues and organs are associated with many human diseases. Searching for molecules able to prevent the formation of fibrils is, therefore, necessary. In this work, we examined the potential of a cocrystal (SS3) of 3-((4-(3-isocyanobenzyl) piperazine-1-yl) methy) benzonitrile with 5-hydroxy isophthalic acid, to prevent fibrillation of human serum albumin. We found that the cocrystal strongly bound to human serum albumin (HSA) with association constant (Ka) of 5.8 ± 0.7 × 105 M-1. The SS3 binding was found to cause small alterations in both secondary and tertiary structure of the protein. Transmission electron microscopy showed that the cocrystal completely prevented the formation of worm-like protofibrils by HSA at SS3/HSA molar ratio of 1:1. The molecule was found to prevent the aggregation in a concentration dependent manner. It was also observed that most of protein in the presence of SS3 remained in soluble state and the secondary structure contained native-like α-helical structure. Therefore, we conclude that the cocrystal effectively prevented conversion of HSA into worm-like protofibril. These finding suggest that combination of molecules in the form of cocrystal or other stable combination could pave a way for the development of drugs against amyloidosis.Communicated by Ramaswamy H. Sarma.

Effect of structural variation on enzymatic activity in tetranuclear (Cu4) clusters with defective cubane core.

The stimulus to the modeling of enzyme functioning sites comes from their potential to give insight into the natural enzyme's mechanistic pathways, ascertain the role of that different metal ion in the active site and construct better catalysts motivated by nature. The presence of metal ion leads to the activation of molecular oxygen in the metalloenzymes. The metalloenzymes such as the catechol oxidase (CO) enzyme that oxidizes the catechol to corresponding quinones which eventually protect damage tissues from plant and pathogen. Thus, the design and characterization of catalysts used as selectively and efficiently oxidation reactions have grown to be unique challenges for modern inorganic chemists. In this work, two novel tetranuclear complexes (1 and 2) have been synthesized in excellent yield. The complexes were characterized using various spectroscopic techniques such as FTIR, UV-Visible and PXRD pattern. The structure of 1 and 2 was elucidated by SC-XRD (single crystal X-ray diffraction) analysis. The magnetic study reveals the presence of the antiferromagnetic nature of 1 and 2. Both 1 and 2 shows a very good catecholase-like activity by oxidizing the catechol to analogous quinone in methanolic solution. Thus, a structure-activity relationship can further help us design other substituted tetranuclear complexes with enhanced catecholase like activity.Communicated by Ramaswamy H. Sarma.