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Six homobimetallic organotin(IV) carboxylates dithiocarboxylates of the general formula R 2 (Cl)SnSSCLCOOSn(Cl)R 2 (R = Me: 1 ; n -Bu: 2 ; Ph: 3 )/R 3 SnSSCLCOOSnR 3 (R = Me: 4 ; n -Bu: 5 ; Ph: 6 ), a trinucleartin(IV) derivative [Ph 2 (Cl)SnSSCLCOO] 2 SnPh 2 ( 7 ), three heterobimetallic (Sn, Pd) products of the type Cl 2 PdSSCLCOOSnR 3 (R = Me: 8 ; Bu: 9 ; Ph: 10 ) and a palladium complex KOOCLCSSPdSSCLCOOK ( 11 ) were synthesized from potassium 1-dithiocarboxylatopiperidine-4-carboxylate ( KSSCLCOOK ) insitu . The structures of the complexes were verified by spectroscopic techniques (FT-IR, UV–Visible, 1 H NMR, 13 C NMR, EI-MS/ESI) and TGA. FT-IR data indicated a bidentate binding mode of the carboxylate/dithiocarbamate group, with tetra and penta-coordinated arrangements around Pd(II) and Sn(IV) centers in solid state. In solution state, a trigonal bipyramidal environment around Sn(IV) and a square planar geometry of Pd(II) was justified by NMR ( 1 H and 13 C) and UV–Vis spectroscopies. In heteronuclear products ( 8 – 10 ), the ligand develops linkage through oxygen and sulfur donor sites to Sn(IV) and Pd(II), respectively. The mass fragmentation and thermal degradation patterns were excellently agreed with the molecular composition of products. Single crystal XRD analysis of the complex 6 demonstrated that the geometry of sulfur bonded tin(IV) lies between tetrahedral and trigonal bipyramidal, while a distorted trigonal bipyramidal arrangement was verified for oxygen bonded Sn(IV). The synthesized complexes exhibited antimicrobial activities against various strains of bacteria and fungi by disc diffusion method and their minimal inhibitory concentrations were also found. The nature of the coordinated metal played a major role in biological actions of such complexes. While Pd(II) incorporation chiefly induces SS-DNA binding capacity and ALPs inhibition in complexes, the coordination with Sn(IV) stimulates the antibacterial and antifungal potentials. The complexes exhibited sufficiently lower hemolytic activities as compared to triton X-100 (positive control, 100% lysis) and higher than PBS (negative control, 0% lysis). [ABSTRACT FROM AUTHOR]

Multinuclear organotin(IV) dicarboxylates of the general formula (Me 3 Sn) 2 L·H 2 O ( 1 ), (Ph 3 Sn) 2 L ( 2 ) and Me 2 SnL[Sn(Cl) 2 Me 2 ] 2 ( 3 ) were synthesized by refluxing disodium iminodiacetate hydrate (Na 2 L·H 2 O) with Me 3 SnCl/Ph 3 SnCl/Me 2 SnCl 2 in methanol. The elemental analysis (C, H and N) data agreed well with the chemical compositions of the products. IR spectroscopy demonstrated a bridging coordination mode of the carboxylate group. 1 H NMR spectroscopy suggested a penta-coordinated environment around the tin(IV) center in complexes 1 and 3 . The title complex 3 represents one of the very few examples of organotin(IV) carboxylates showing simultaneously coordination with dimethyltin(IV) as well as dichlorodimethyltin(IV) moieties, by substitution and addition reactions, respectively. The 13 C NMR spectroscopy demonstrated the carboxylate-metal linkages. EIMS and ESI spectra verified the molecular skeletons of the products 1 – 3 . Thermogravimetric analysis revealed the bimetallic nature of 2 . A single crystal XRD study of 3 has shown a predominantly square pyramidal geometry with some trigonal bipyramidal characteristics around each metal center. The novel products exhibited antibacterial/antifungal potential and their minimal inhibitory concentrations (MIC) were also evaluated. In vitro hemolytic studies on human red blood cells indicated a slightly toxic nature of the synthesized complexes. [ABSTRACT FROM AUTHOR]

Three new amphiphilic compounds i.e., n-decyl-3-methylpyridinium bromide ( a), n-dodecyl-3-methylpyridinium bromide ( b), and n-tetradecyl-3-methylpyridinium bromide ( c), have been synthesized by condensation reaction and characterized by NMR (H, C) and FTIR spectroscopic techniques. The micellization behavior of the compounds has been studied in ethanol employing conductometry and UV/visible spectroscopy. The critical micellization concentration (CMC) values for compound a, b and c was found to be 0.31, 0.29 and 0.27 m mol L, respectively. Effect of temperature on the CMC was checked in the range of 298-318 K. The thermodynamic parameters such as Δ G, Δ H and Δ S of the micellization process of these surfactants were computed. The negative values of Δ G and positive values of Δ H indicated the spontaneous and endothermic nature of the micellization process. Antimicrobial activities of these amphiphiles showed significant activity against different bacterial strains. [ABSTRACT FROM AUTHOR]

Organotin(IV) thiocarboxylates R2SnL2(R = Me:1:Ph:2)/R2(Cl)SnL (R = n-Bu:3; Ph:4)/R3SnL (R = Me:5;n-Bu:6; Ph:7), where L = 4-(2-hydroxyethyl)piperazine-1-carbodithioate, have been synthesized by stirring together 1,2-hydroxyethylpiperazine and CS2in methanol, and then refluxing with a di-/triorganotin chloride. The synthesized products have been characterized by various spectroscopic (IR,1H NMR,13C NMR, EI-MS) techniques and single crystal XRD. FT-IR data indicate bidentate binding of the ligand. The magnitude of2J(119Sn–1H) demonstrated a skew trapezoidal environment around tin(IV) in1,whereas the metal geometry in5was between distorted tetrahedral and trigonal bipyramidal in solution.13C NMR revealed four- and five-coordinate environments in6and7, respectively, in non-coordinating solvent. EI-MS data agreed very well with the structural skeleton of the products. Single crystal XRD study has shown skew trapezoidal- and trigonal-bipyramidal Sn(IV) in1and7, respectively. Compound6interacted with salmon sperm DNA (SS-DNA) with significant hypochromic effect and an intercalating mode of binding. Diorganotin(IV) derivatives (2and3) generally exhibited poor antibacterial/antifungal potential as compared to their trialkyltin(IV)/triaryltin(IV) counterparts (5and6). Thein vitrohemolytic activities show that average lysis of human red blood cells caused by1–7was significantly lower compared to triton X-100 (positive control, 100% lysis) and not very much higher than PBS (negative control, 0% lysis). [ABSTRACT FROM AUTHOR]

Ten complexes of sodium salt of pyrrolidine-1-carbodithioate with mono, di and tri-organotin(IV) derivatives, [SnR 3 (S 2 CR′); {R′ = pyrrolidine, R = CH 3 ( 1 ), C 2 H 5 ( 2 ) C 6 H 11 ( 3 ), CH 2 -C 6 H 5 ( 4 )}; SnR 2 (S 2 CR′) 2 ; {R = CH 3 ( 5 ), C(CH 3 ) 3 ( 6 ) CH 2 -C 6 H 5 ( 7 )}; SnRCl 2 (S 2 CR′); {R = C 4 H 8 ( 8 ), C 6 H 5 ( 9 , 10 )], have been synthesized and characterized by elemental, FT-IR and multinuclear NMR ( 1 H, 13 C and 119 Sn) techniques. The FT-IR data reveals that in triorganotin(IV) the CSS unit acts as a monodentate (Δ ν asym is >20) while in mono and diorganotin(IV) derivatives it acts bidentate as the difference (a single and unsplit peak is observed). The crystal structures of the complexes 3 , 5 , 6 and 9 were also determined by X-ray single crystal analysis. In complex 3 the geometry around of tin atoms is 4-coordinated tetrahedral while complex 9 demonstrated 5-coordinated geometry trigonal bipyramidal. Complexes 5 and 6 show 6-coordinated octahedral geometry. They were also screened for interaction with DNA by UV–visible spectroscopy. From the UV–visible spectroscopic result it was confirmed that the binding mode of these compounds with DNA is an intercalation. This was further conformed by viscosity measurements. The screening results show that the complex exhibit good antibacterial activity. POM analyses reveal that the compounds are slightly toxic and present a potential antibacterial activity. Moreover, they have 5–85% drug score which is an important parameter for the compound possessing the drug properties. [ABSTRACT FROM AUTHOR]

The present study deals with the synthesis of ligand 4-oxo-4-(thiazol-2-ylamino)butanoic acid and afterward its organotin(IV) carboxylates [BuSnL] ( 1), [PhSnL] ( 2), [MeSnL] ( 3), [BuSnL] ( 4) and [PhSnL] ( 5). These complexes were characterized by useful techniques like elemental analysis, FT-IR, NMR (H, C) and single crystal analysis. The ligand coordinates to tin atom via the carboxylate group. Complex 1 has also been studied by single crystal XRD analysis. It showed that tin has distorted tetrahedral geometry due to bulky butyl groups that hinder the carbonyl oxygen of the ligand interaction with the adjacent tin atom for further coordination. The HOMO-LUMO study of ligand ' HL' and its tin complexes 3 and 5 indicated that tin complexes are thermodynamically more stable than the ligand. The synthesized complexes were screened for their biological activities like antibacterial, antifungal, antileishminial, cytotoxicity and protein kinase inhibition studies in vitro. Complexes 1 and 2 exhibited maximum antileishmanial activity that was even higher than that of standard Amphotericin B, with significant cytotoxicity and could be potential candidates for the treatment of leishmaniasis. The UV-visible spectroscopic studies revealed that ligand and its complexes bind with DNA via intercalative mode of interaction leading to hypochromism and minor bathochromic or hypsochromic shifts. [ABSTRACT FROM AUTHOR]

Diorganotin(IV) derivatives have been synthesized by the reaction of R2SnL2 (R= n-Bu 1, Ph 2) with monohydrate disodium salt of iminodiacetic acid ( Na2L) in 1 : 1 M/L ratio under reflux conditions. The compounds have been characterized by FT-IR, NMR (1H and 13C) spectoscopy, electron ionization mass spectrometry (EIMS), thermogravimetric analyses (TGA) and single crystal XRD. FTIR data indicates a mono-dentate binding mode of the carboxylic acid group as well as participation of the amino nitrogen and aqua oxygen in coordination with organotin(IV) moieties. NMR data demonstrates a tetra-coordinated environment around tin(IV) in solution. Mass spectrometric and thermogravimetric analyses verify the close similarities between the molecular structures of both complexes. The thermal stability of diphenyltin(IV) derivative ( 2) was found slightly higher than that of the free ligand ( Na2L). Single crystal X-ray analysis of the complex 1 have shown a hexa-coordinated geometry around Sn(IV) with trans configuration. There are evidences for the existence of intermolecular hydrogen bonding in the structure of the complexes. The products displayed significant antibacterial and antifungal activities in contrast to the biologically inactive ligand precursor. However, the hemolytic cytoxicity of the complexes was comparatively high than the free ligand. [ABSTRACT FROM AUTHOR]

A new binuclear O-bridged Cu(II) complex with 4-chlorophenyl acetate and 2,2′-bipyridine has been synthesized and characterized using FT-IR, powder and single crystal XRD and electrochemical solution studies. The results revealed that the two penta-coordinated Cu(II) centers are linked by two carboxylate ligands in end-on bonding fashion. The coordination geometry is slightly distorted square pyramidal (SP) with bridging oxygen atoms occupying the apical position and other ligands lying in the equatorial plane. The striking difference in Cu–O bond distance of the bridging oxygen atom in the complex may be responsible for the SP geometry of Cu(II) ion. The complex gave rise to metal centered irreversible electro-activity where one electron Cu(II)/Cu(III) oxidation process and a single step two electron Cu(II)/Cu(0) reduction process was observed. The redox processes were found predominantly adsorption controlled. The values of diffusion coefficient and heterogeneous rate constant for oxidation process were 6.98 × 10 −7 cm 2 s −1 and 4.60 × 10 −5 cm s −1 while the corresponding values for reduction were 5.30 × 10 −8 cm 2 s −1 and 5.41 × 10 −6 cm s −1 , respectively. The formal potential and charge transfer coefficient were also calculated. The DNA-binding ability was explored through cyclic voltammetry and UV–Visible spectroscopy. Diminution in the value of D o for oxidation indicated the binding of the complex with DNA corresponding to K b = 8.58 × 10 4 M −1 . UV–Visible spectroscopy yielded ε = 49 L mol −1 cm −1 and K b = 2.96 × 10 4 M −1 . The data of both techniques support each other. The self-induced redox activation of the complex, as indicated by cyclic voltammetry heralds its potential applications in redox catalysis and anticancer activity. [ABSTRACT FROM AUTHOR]

New organotin(IV) complexes have been synthesized by treating potassium o-isopropyl carbonodithioate with R2SnCl2/R3SnCl in 1 : 2/1 : 1 M/L ratio. All complexes have been characterized by IR and NMR (1H, 13C) spectroscopy. IR results shows that ligand acts as bidentate which is also confirmed by semi-empirical study. NMR data reveals four coordinated geometry in solution. Computed positive heat of formation shows that complex 5 is thermodynamically unstable. UV/visible spectroscopy was used to assess the mode of interaction and binding of the complexes with DNA which shows that complex 5 exhibits higher binding constant as compared to complex 3. In protein kinase inhibition assay, compound 3 was found most active, while other biological activities shows that triorganotin(IV) complexes are biologically more active as compared to diorganotin(IV) complexes. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) is a universal network to supervise the physical world through sensors installed on different devices. The network can improve many areas, including healthcare because IoT technology has the potential to reduce pressure caused by aging and chronic diseases on healthcare systems. For this reason, researchers attempt to solve the challenges of this technology in healthcare. In this paper, a fuzzy logic-based secure hierarchical routing scheme using the firefly algorithm (FSRF) is presented for IoT-based healthcare systems. FSRF comprises three main frameworks: fuzzy trust framework, firefly algorithm-based clustering framework, and inter-cluster routing framework. A fuzzy logic-based trust framework is responsible for evaluating the trust of IoT devices on the network. This framework identifies and prevents routing attacks like black hole, flooding, wormhole, sinkhole, and selective forwarding. Moreover, FSRF supports a clustering framework based on the firefly algorithm. It presents a fitness function that evaluates the chance of IoT devices to be cluster head nodes. The design of this function is based on trust level, residual energy, hop count, communication radius, and centrality. Also, FSRF involves an on-demand routing framework to decide on reliable and energy-efficient paths that can send the data to the destination faster. Finally, FSRF is compared to the energy-efficient multi-level secure routing protocol (EEMSR) and the enhanced balanced energy-efficient network-integrated super heterogeneous (E-BEENISH) routing method based on network lifetime, energy stored in IoT devices, and packet delivery rate (PDR). These results prove that FSRF improves network longevity by 10.34% and 56.35% and the energy stored in the nodes by 10.79% and 28.51% compared to EEMSR and E-BEENISH, respectively. However, FSRF is weaker than EEMSR in terms of security. Furthermore, PDR in this method has dropped slightly (almost 1.4%) compared to that in EEMSR. [ABSTRACT FROM AUTHOR]

New organotin(IV) carboxylates, R2SnL2(R=n-Bu:1), R2Sn(Cl)L (R=n-Bu:2), and R3SnL (R=Me:3;n-Bu:4; Ph:5) have been synthesized by stirring 5-chloro-2-hydroxybenzoic acidHLwith KOH and R2SnCl2(R=n-Bu)/R3SnCl (R=Me,n-Bu, Ph) in methanol at room temperature. The complexes along with ligand have been characterized by FTIR, (1H,13C) NMR, EI-MS, and single-crystal XRD crystallography. FTIR data indicated bidentate coordination of carboxylate. NMR data suggested six- or five-coordinate geometry of organotin(IV) carboxylates. Single-crystal XRD of1demonstrated skew-trapezoidal geometry around the tin center, with the basal plane occupied by four oxygens and the two butyl groups lying in distorted axial position. Complexes1,2,and5exhibited interaction with SS-DNA (salmon sperm) and suggests intercalating mode of binding. The complexes displayed significant antimicrobial activities against bacterial and fungal strains as compared to free ligand. The hemolytic activity of the complexes was lower compared to Triton-X 100 (positive control, 100% lysis) and higher than phosphate-buffered saline (negative control, 0% lysis). Complex4was the most potent inhibitor of bacterial/fungal growth. [ABSTRACT FROM PUBLISHER]

Heterobimetallic complexes have been synthesized by stirring 2-mercapto-5-methylbenzimidazole with carbon disulfide in methanol at room temperature. In the second step, the product was treated with R2SnCl2/R3SnCl (R = Me,n-Bu, Ph) in 1 : 1 M ratio, then organotin(IV) complexes were treated with HgCl2in 2 : 1 M : L ratio to yield heterobimetallic complexes. The ligand and complexes have been characterized by elemental analysis, IR,1H- and13C NMR spectroscopy, mass spectrometry (EI-MS), and semiempirical study to assess the binding mode of the heterobimetallic complexes. IR data showed the bidentate nature of the dithiocarbamate moiety, which is also confirmed by semiempirical study. Mass spectra correspond to the expected for the complexes. NMR spectroscopy confirmed the four-coordinate geometry in solution. Computed molecular descriptors, thermodynamic parameters, and electrostatic surface potential map of4were calculated by using the PM6 method. Biological screening data indicated that complexes exhibit significant activity against various bacterial and fungal strains with few exceptions. Ligand and6are excellent for phagocyte reactive oxygen species inhibition. [ABSTRACT FROM PUBLISHER]

UV/O3 radiation and chemical resistant nanocomposite films of functionalized/metal decorated multiwall carbon nanotubes (MWCNTs) with polymethylmethacrylate (PMMA) are synthesized. Silver nanoparticles are decorated on the surface of UV/O3 functionalized MWCNTs by both reduction and in situ growth from AgNO3 aqueous solution. Microscopic studies reflect the better dispersion of UV/O3 functionalized/silver decorated MWCNTs in polymer matrix contributing in enhancement of thermal stability, thermomechanical strength, glass transition temperatures, and thermal conductivity of nanocomposites even at 0.25 wt% MWCNTs additions. The thermal stability of nanocomposite film (0.25 wt% loading), prepared by using a surfactant (Sodium dodecyl sulfate) is increased to about 27°C while the thermomechanical properties are raised up to 76% at 100°C. Thermal and thermomechanical behavior of pre- and post-UV/O3 irradiated nanocomposite films are compared with neat polymer. The results reveal that UV/O3 functionalized MWCNTs can effectively disperse the radiation and have a dramatic reinforcement effect on the nature of the degradation of PMMA matrix. POLYM. COMPOS., 36:969-978, 2014. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

N-[(4-methoxyphenyl)]-4-oxo-4-[oxy]butanamide was synthesized and characterized by various techniques like elemental analyses, FT-IR, NMR ( 1 H, and 13 C), mass spectrometry and single crystal X-ray structural analysis. The appearance of the OH peak of the carboxylic acid in the FT-IR and NMR spectra conform the formation of the compound. The molecular structure of the compound is stabilized by short intramolecular O–H⋯O hydrogen bonds within the molecule. The synthesized compound was screened for in vitro biological activities like antimicrobial, anticancer, antileishmanial activities as well as interaction with SS-DNA (Salmon sperm DNA). It shows good antimicrobial activity. The in vitro anticancer activity against lung carcinoma (H157) and Vero cell lines demonstrate that the synthesized compound has almost comparable activity to that of the standard anticancer drug, vincristine. The biological importance of the compound is that it has almost no effect (less than 26.7%) on the normal cell line, Vero cell line. It was also tested for antileishmanial activity against the promastigote form of leishmania major and obtained attractive result. It was also tested for urease inhibition and showed good inhibitory activity against jack bean urease (IC 50 = 4.08 ± 2.54 μM). UV–Vis spectroscopic result reveals that the binding mode of interaction of the compound with SS-DNA is intercalative DNA interaction and the intercalative mode of interaction was further supported by viscometry. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nanocomposite of functionalized CNTs with Fe3O4 nanoparticles is prepared. [•] Good quality interfacial adhesion between CNTs and Fe3O4 matrix. [•] High discharge capacity of 1093mAhg−1 after 50 cycles. [•] 50th Cycle coulombic efficiency of 98.4% at a current density of 100mAg−1. [ABSTRACT FROM AUTHOR]

Fourteen new organotin(IV) complexes with general formula R2SnL2 or R3SnL where R = CH3, C2H5, C4H9, C6H5, C6H11, CH2-C6H5, C(CH3)3, C8H17 and L = N-[(2-methoxyphenyl)]-4-oxo-4-[oxy]butanamide were synthesized and characterized by elemental analyses, FT-IR, NMR (¹H, 13C and 119Sn), mass spectrometry and single crystal X-ray structural analysis. Crystallographic data for four triorganotin(IV) complexes (R3SnL, R = CH3, C2H5, C4H9, CH2-C6H5) showed the tin has approximate trigonal bipyramidal geometry with the R groups in the trigonal plane. The carboxylate groups of ligands L bridge adjacent tin atoms, resulting in polymeric chains. In case of the diorganotin(IV) derivatives a six-coordinate geometry at the tin atom is proposed from spectroscopic evidence. The Me-Sn-Me bond angle in complex 7 was determined from the ² J[119Sn-¹H] value as 166.3° that falls in the range of six-coordinate geometry. The ligand and its complexes (1-14) were screened for their antimicrobial, antitumor, cytotoxic and antileishmanial activities and found to be biologically active. The ligand and its complexes bind to DNA via intercalative interactions resulting in hypochromism and minor bathochromic shifts as confirmed by UV-visible spectroscopy. Based on in vitro studies such as the potato disc method, the synthesized compounds were found to possess significant antitumor activity. Also, from cytotoxicity and DNA interaction studies, these compounds can also be used for the prevention and treatment of cancer. Gel electrophoresis assay was used to investigate the damage to double stranded super coiled plasmid pBR322 DNA by the synthesized compounds and compounds 1 and 7 were found to cause the maximum damage. All the synthesized compounds exhibit strong antileishmanial activity that was even higher than that of Amphotericin B, with significant cytotoxicity. This study, therefore, demonstrated the potential use of these compounds as source of novel agents for the treatment of leishmaniasis. [ABSTRACT FROM AUTHOR]

The homogeneous nanocomposites (NC) films of amino modified and metal decorated multiwall carbon nanotubes (MWCNTs) with polymethylmethacrylate (PMMA) were synthesized through in-situ free radical polymerization. Silver metal nanohybrids (Ag/MWCNTs) were prepared by two strategies, that is, reduction of metal salt in presence of sodium dodecyl sulfate and in-situ growth from AgNO3 aqueous solution. The amino functionalization by ball milling enhanced the dispersion of MWCNT in monomer and produced a new class of radiation resistant NC. These synthesized films were characterized by FTIR, TGA, TEM, EDX, TC, DMA, and optical microscopy to ascertain their structural morphologies, thermal stability, and mechanical strength. Microscopic studies reflect the homogeneous mixing of amino functionalized and metal decorated MWCNTs in polymer matrix contributing in the enhancement of thermal stability, thermomechanical strength, glass transition temperatures, and thermal conductivity of NC even at 0.25 wt% addition of modified nanofiller. The thermal stability of NC film at 0.25 wt% loading was increased around ≂50°C and the raise of thermo-mechanical properties was observed up to 85% at 100°C in the presence of adsorbed surfactant. Thermal and thermomechanical behavior of pre and post UV/O3 irradiated NC films has been compared with neat polymer. The results revealed that amino modified nanofiller embedded network in polymer matrix can effectively disperse the radiation and has a dramatic reinforcement effect on the nature of degradation of PMMA matrix. [ABSTRACT FROM AUTHOR]

Three transition metal and six organotin(IV) complexes have been synthesized by treating potassiumo-methyl carbonodithioate with ZnCl2/CdCl2/HgCl2and R2SnCl2/R3SnCl under stirring. The complexes were characterized by IR,1H, and13C NMR spectroscopies. IR results show that the ligand is bidentate in1–3while monodentate in4–9, which is also confirmed by semi-empirical study. NMR data reveal four-coordinate geometry in solution. HOMO–LUMO study shows that7and9are thermodynamically unstable. The enzyme inhibition study shows that1is a potent inhibitor of ALP, EC 3.1.3.1, resulting in very slow rate of formation and breakdown of enzyme–substrate complex. UV/visible spectroscopy was used to assess the mode of interaction and binding of the complexes with DNA which shows that9exhibits higher binding constant when compared to6. In protein kinase inhibition assay,1was active, while antifungal activity shows that organotin(IV) complexes are more active than transition metal complexes. [ABSTRACT FROM AUTHOR]

Context: Trypanosoma brucei brucei ( T.b. brucei) infection causes death in cattle, while the current treatments have serious toxicity problems. However, natural products can be used to overcome the problems associated with parasitic diseases including T.b. brucei. Objective: Artemisia elegantissima Pamp (Asteraceae) was evaluated phytochemically for its constituents and antitrypanosomal potential against T.b. brucei for the first time. Scopoletin isolated from A. elegantissima has shown better potential then the standard drug suramin, used against T.b. brucei. Materials and methods: The ethanol extract of the aerial parts of A. elegantissima was fractionated by column and preparative thin-layer chromatography into six fractions ( A-F) yielding 13 compounds, these were evaluated for their antitrypanosomal activity against T.b. brucei at different concentrations. Results: Thirteen compounds were isolated from A. elegantissima: ( Z)- p-hydroxy cinnamic acid, stigmasterol, β-sitosterol, betulinic acid, bis-dracunculin, dracunculin, scopoletin, apigenin, dihydroluteolin, scoparol, nepetin, bonanzin, and 3′,4′-dihydroxy bonanzin. The fractions D-F were found to be active at the concentration of 20 µg/ml and three compounds isolated from these fractions, scopoletin (MIC ≤0.19 µg/ml), 3′,4′-dihydroxy bonanzin (MIC = 6.25 µg/ml) and bonanzin (MIC = 20 µg/ml), were found to be highly active. Discussion and conclusion: Artemisia elegantissima was phytochemically and biologically explored for its antitrypanosomal potential against T.b. brucei. The number and orientation of phenolic hydroxyl groups play an important role in the antitrypanosomal potential of coumarins and flavonoids. The compounds 3′,4′-dihydroxy bonanzin and scopoletin with low MIC values, hold potential for use as antitrypanosomal drug leads. [ABSTRACT FROM AUTHOR]

Three diorganotin(IV) complexes of general formula R 2 Sn[(O)C 10 H 6 CHN 2 CH(O)] have been synthesized by the interaction of dimethyltin(IV) dichloride, diphenyltin(IV) dichloride, di- tert -butyltin(IV) chloride and novel ligand N′-(2-hydroxynaphthalen-1-yl)methylene)formohydrazide in toluene. Spectroscopic and single crystal X-ray studies confirm coordination of dibasic tridentate ligand to the diorganotin(IV) moieties via ONO donor sites and formation of pentacoordinated tin center. Furthermore, antibacterial screening, cytotoxicity assessment and docking study for the synthesized compounds have also been carried out. [Display omitted] Three organotin(IV) complexes [Me 2 SnL(1), Ph 2 SnL(2), tert -Bu 2 SnL(3)] have been synthesized by the reaction of a novel ligand N'-(2-hydroxynaphthalen-1-yl)methylene)formohydrazide (H 2 L) with dialkyltin(IV) dichlorides [R 2 SnCl 2 (R = Me, Ph, tert -Bu) in presence of Et 3 N. The ligand and complexes have been characterized by elemental analysis, mass spectrometry, FT-IR, 1H, 13C and 119Sn NMR spectroscopic techniques. The spectroscopic data suggests coordination of ligand to the diorganotin(IV) moieties via oxygen nitrogen donor sites and five coordinated tin centers. The molecular structures of ligand (H 2 L) and complexes (1, 3) were also confirmed by single crystal X-ray analysis. The solid state structure of ligand showed it to be in the amido form whereas the single crystal X-ray analysis of complexes revealed the dibasic tridentate nature of ligand and monometallic nature of complexes. In both the complexes (1, 3) the Sn atom is in a distorted five-coordinate square pyramidal geometry with trigonality index(τ) 0.33 and 0.41, respectively. Packing diagrams reveal the important role of H ... H, C H ... π and O ... H interactions in generating the supramolecular assembly. The antibacterial potential of all the compounds was investigated against two gram-positive bacteria (Bacillus subtilis, Stephlococcus aureus) and four gram-negative bacterial strains (Escherichia coli, Shigella flexenari, Pseudomonas aeruginosa, Salmonella typhi), using imipenem as the standard drug. Complex 2 exhibited highest activity against Bacillus subtilis and highest cytotoxicity against brine shrimp nauplii with LD 50 1.01 μg/mL. Molecular Docking investigations revealed the best target protein, the positive impact of diphenyltin(IV) moiety on the compound-protein binding and the important role of hydrogen bonding, pi-pi and hydrophobic forces in such type of interaction. [ABSTRACT FROM AUTHOR]

Abstract The purpose of this study is to test and validate a modified stimulus organism response (SOR) theory with a bi-dimensional attitude toward fake news sharing. This study examines the effect of various gratifications, i.e., hedonic, social, and utilitarian, with bi-dimensional attitudes and intentions toward sharing fake news. The moderating effect of social networking sites (SNS) dependency is also investigated to examine the attitude-intention gap. Data were collected from a sample of 327 social media users and further analyzed using PLS-SEM. The modified SOR theory described significant variance in fake news sharing intentions. Findings reveal that cognitive attitude is a strong predictor of sharing fake intentions than affective attitude. All gratifications factors except hedonic gratification have significant positive association with attitude which in turn influence the users’ toward fake news sharing. Moreover, the findings also proved the moderating effect of SNS dependency. This study explains remarkable insights for researchers, practitioners, social media users, and social media platform providers. [ABSTRACT FROM AUTHOR]

We report one-pot synthesis of zinc(II) complexes with 4-nitrocinnamic acid (HL), [ZnL2(H2O)2] (1), [ZnL2(DMSO)2] (2) and [Zn(en)2(H2O)2]L2(H2O)2(3), where DMSO?=?dimethylsulfoxide and en?=?ethylenediamine. The complexes were prepared by reacting sodium 4-nitrocinnamate with zinc acetate in aqueous medium and characterized by FT-IR, NMR and single crystal X-ray diffraction. The results have shown distorted octahedral geometry for1and3while tetrahedral for2where the carboxylate coordinated bidentate and monodentate in1and2is uncoordinated in3, replaced completely by ethylenediamine. The complexes were also screened for their DNA interaction and alkaline phosphatase (ALP) inhibition using cyclic voltammetry, viscometry and UV–visible spectroscopy. All these techniques indicated strong electrostatic binding of the complexes with DNA. The diffusion coefficients of the complexes decreased on DNA addition indicating binding of the complexes with DNA. The binding constants were also calculated through CV and UV spectra. The complexes were screened for ALP inhibition activity as well, where 80% activity was found for1. The synthesized compounds interact with DNA via intercalative mode of interaction. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Bidentate nature of 2-thiophene carboxylic acid hydrazide. [•] Thermodynamic parameters shows the stability of oxovanadium complexes. [•] DNA binding study suggests the intercalative binding mode of the complexes with DNA. [•] Ligand and synthesized complexes are found to be active inhibitors of urease. [•] Lack of antimicrobial activity against tested bacterial and fungal strains. [Copyright &y& Elsevier]

A series of six organotin(IV) carboxylates [MeSnL] ( 1), [ n-BuSnL] ( 2), [ n-OctSnL] ( 3), [MeSnL] ( 4), n-BuSnL ( 5) and [PhSnL] ( 6), where L = 3-(4-cyanophenyl) acrylic acid have been synthesized and characterized by elemental analysis, FT-IR and NMR (H, C). The complex ( 4) was also analyzed by single crystal X-ray analysis which showed distorted trigonal bipyramidal geometry with polymeric bridging behavior. The complexes 1- 6 were screened for antimicrobial activities and cytotoxicity. The results showed significant activity with few exceptions. The catalytic activity of complexes was assessed in transesterification reaction of Brassica campestris oil (triglycerides) to produce biodiesel (fatty acid methyl esters). The results showed that triorganotin(IV) complexes exhibited good catalytic activity than their di-analogues. [ABSTRACT FROM AUTHOR]

Dimeric paddlewheel copper(II) complex, pyCu(phenylacetate)4Cupy, where py = pyridine, has been prepared and the crystal structure determined. Single crystal X-ray diffraction (XRD) revealed three crystallographically independent molecules in the unit cell. The geometry around each Cu(II) is square pyramidal with monodentate pyridine at the apical and bidentate carboxylates in the equatorial positions. The supramolecular structure of the complex arises primarily as a result of C–H⋯O along with some contribution of C–H⋯C interactions, resulting in the preferential alignment of the molecules along thec-axis. The purity of the crystalline complex has been confirmed through powder XRD study. Electrochemical solution study of the complex in aqueous DMSO (1 : 4) showed two redox couples corresponding to Cu(III)/Cu(II) and Cu(II)/Cu(I) irreversible electron transfer. The values of various voltammetric variables, such as diffusion coefficient (Do), heterogeneous rate constant (k°), formal potential (E°), and charge transfer coefficient (α), have been calculated before and after DNA addition. DNA binding of the complex has been explored through cyclic voltammetry, UV–visible spectrophotometry, and viscosity measurement which have exhibited a mixed electrostatic and intercalative mode of interaction. Cyclic voltammetry indicated self-induced redox activation and potential anticancer ability of the complex, supported by UV–visible spectrophotometry as well as viscometry. [ABSTRACT FROM AUTHOR]

Trimethyl (1), tributyl (2), and triphenyl tin (3) derivatives of sodium (R)-4-((3R,5R,8R,9S,10S,12S,13R,14S,17R)-3,12-dihydroxy-10,13-dimethyl-hexadecahydro-1H-cyclopenta[a]phenanthren-17-yl)pentanoate (sodium deoxycholate) were synthesized by refluxing sodium deoxycholate with the corresponding triorganotin(IV) chloride in 1 : 1 M ratio. All the three compounds were characterized by elemental analysis, infrared spectroscopy,1H,13C,119Sn NMR, and X-ray diffraction studies. From FT-IR spectra, Δνvalues proposed bridging or chelating behavior of the ligand. The three compounds gave a trigonal bipyramidal geometry in the solid state and tetrahedral geometry in solution. Single crystal of1showed polymeric trigonal bipyramidal geometry. Synthesized compounds obtained were screened for their antimicrobial and antitumor activities against A2780 cell line. Results revealed that only2showed significant antibacterial activity. However, all the three compounds exhibited promising antifungal and anticancer activities. The synthesized compounds inhibit strong antifungal activity even higher than the standard drug,Turbinafine. Keeping in view their antifungal activity, they might be used as potent antifungal agent. [ABSTRACT FROM AUTHOR]

Eight different di- and triorganotin(IV) complexes of vanillin-Schiff base of the type RSnClL and RSnL [R = Me ( 1, 6), n-Bu ( 2, 7), Ph ( 3, 8), tert-Bu ( 4), Cy ( 5) and L = 4-((3,5-dimethylphenylimino)methyl)-2-methoxyphenol] were synthesized. The products were characterized by elemental analysis, FT-IR, H, C and Sn NMR spectroscopy. The ligand 4-((3,5-dimethylphenylimino)methyl)-2-methoxyphenol is also characterized by single crystal X-ray analysis. In the H NMR spectra of 1 and 6, the J(Sn-H) in the Sn-CH moiety has 57 and 54 Hz values, respectively, that confirm the formation of four-coordinated Sn species. Moreover, the C NMR value for ipso carbon of SnPh is 139 ppm which also confirms the formation of four-coordinated Sn species. The title ligand and its complexes were also screened for their biological activities such as interaction with DNA, enzymatic, antimicrobial, cytotoxic and antioxidant activities. The antimicrobial and cytotoxic activities of triorganotin(IV) derivatives are relatively higher than their corresponding diorganotin(IV) analogues due to their greater lipophilicity and permeability through cell membrane. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] Synthesis of jojoba seed oil biodiesel by base and organotin catalysts. [•] Effect of various parameters on % conversion of biodiesel. [•] Determination of physical and fuel properties. [•] Spectroscopic (FTIR and NMR) characterization. [•] Identification of fatty acid methyl esters by GC–MS. [ABSTRACT FROM AUTHOR]

A series of organotin(IV) complexes has been synthesized by reacting 4-piperidine carboxamide with CS2and R2SnCl2/R3SnCl in 1 : 1 M/L ratio at room temperature. The synthesized complexes were further treated with benzaldehyde to synthesize Schiff bases under stirring. All the complexes were characterized by elemental analysis, FT-IR,1H and13C NMR. FT-IR and semi-empirical study confirm the bidentate nature of ligand. The complexes exhibit four-coordinate geometry in solution. Thermodynamic parameters and molecular descriptors were calculated by using semi-empirical PM3 method. HOMO–LUMO calculations show that chlorodiorganotin complexes are more susceptible to nucleophilic attack when compared with triorganotin complexes. Negative heats of formation at 298 K demonstrate that1,4,and7are thermodynamically stable. The antimicrobial results have shown that complexes containing Schiff base exhibit significantly better activity compared to complexes with carboxamide derivatives. [ABSTRACT FROM PUBLISHER]

A series of organotin(IV) carboxylates, [Me2SnL2] (1), [Bu2SnL2] (2), [Oct2SnL2] (3), [Me3SnL] (4), and [Ph3SnL] (5), where L = 2-(4-ethylbenzylidene) butanoic acid, have been synthesized and characterized by elemental analysis, FT-IR, and NMR (1H,13C, and119Sn). [Me3SnL] (4) was analyzed by single crystal X-ray analysis which showed polymeric structure with distorted trigonal bipyramidal geometry. The complexes were screened for biological activities including antibacterial, antifungal, and cytotoxic activities. UV–vis absorption studies ofHL,1and4with SS-DNA revealed groove binding as well as intercalation, which may be due to the presence of planar phenyl groups that facilitate interaction with DNA. The determined intrinsic binding constants, 6.04 × 103 M−1(HL), 9.6 × 103 M−1(1), and 1.7 × 104 M−1(4), showed thatHLand1have less binding strength than4. The catalytic activities of di- and tri-organotin(IV) complexes were assessed in transesterification of triglycerides (linseed oil) into fatty acid methyl esters (biodiesel). The tri-organotin(IV) complexes have better catalytic activity than their di-analogs. The synthesized compounds interact with SS-DNA via intercalative binding mode of interaction in which the compound insert itself into the base pair of DNA resulting in hypochromic and bathochromic shift. [ABSTRACT FROM PUBLISHER]

Organotin (IV) carboxylates with the general formulae R2Sn(Cl)L [R =Me (1), n-Bu (2), Ph (3)] and R3SnL [R =Me (4), Ph (5)] have been synthesized by the reaction of 4-piperidine carboxylic acid (HL) with KOH and R2SnCl2 (R =Me, n-Bu, Ph)/R3SnCl (R =Me, Ph) in methanol under stirring conditions. The metal ligand binding site, structure, and stability of complexes have been verified by FT-IR, (¹H, 13C) NMR, EI-MS technique, and semiempirical study. The FT-IR data indicate the bidentate chelating mode of the carboxylate ligand which is also confirmed by semiempirical study. In solution state, five and four coordinated geometry around tin was confirmed by NMR spectroscopy. The EI-MS data agreed well with the molecular structure of the complexes. Thermodynamic parameters and molecular descriptors were calculated by using semiempirical PM3 method. HOMO-LUMO calculations show that chlorodiorganotin complexes are more susceptible to nucleophilic attack as compared to triorganotin complexes. Computed negative heat of formation indicates that complexes 1-4 are thermodynamically stable. The organotin(IV) carboxylates displayed powerful antimicrobial activities against various strains of bacteria and fungi and their minimal inhibitory concentration were also evaluated. The complexes exhibited comparatively higher hemolytic activity as compared to free ligand. [ABSTRACT FROM AUTHOR]

Highlights: [•] Synthesis of new six organotin(IV) derivatives of 3-(4-cyanophenyl)-2-methylacrylic acid. [•] Single crystal analysis of complexes 4 and 6. [•] DNA interaction studies of complexes by UV–Vis spectrophotometer and viscometry. [•] All complexes (1–6) have been tested for their anti-bacterial and anti-fungal activities. [•] Catalytic activity of complexes was assessed in synthesis of biodiesel. [ABSTRACT FROM AUTHOR]

A series of organotin(IV) complexes, [Bu2Sn(C6H5O2S)2] (1), [Bu3Sn(C6H5O2S)] (2), [Oct2Sn(C6H5O2S)2] (3) of 2-thiopheneacetic acid (HL) have been prepared and characterized through FT-IR and NMR spectroscopy. The crystal structure of2has been confirmed by X-ray single crystal analysis, in which tin adopts a trigonal bipyramidal geometry. The synthesized complexes have been screened for antibacterial, DNA protection, and enzyme inhibition activities against acetylcholinesterase as well as butylcholenesterase. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer is a deadly disease that needs to be diagnose at early stage to increase patient survival rate. Multi-organ (such as breast, brain, lung, and skin) cancer detection, segmentation and classification manually using medical imaging is time consuming and required high expertise. In this study, we summarize existing deep learning segmentation and classification methods for multi-organ cancer diagnosis and provide future challenges with possible solutions. This review may benefit researchers to design new robust approaches that could be useful for the medical specialists as a second view. Thus far, the most common cause of death in the world is cancer. It consists of abnormally expanding areas that are threatening to human survival. Hence, the timely detection of cancer is important to expanding the survival rate of patients. In this survey, we analyze the state-of-the-art approaches for multi-organ cancer detection, segmentation, and classification. This article promptly reviews the present-day works in the breast, brain, lung, and skin cancer domain. Afterwards, we analytically compared the existing approaches to provide insight into the ongoing trends and future challenges. This review also provides an objective description of widely employed imaging techniques, imaging modality, gold standard database, and related literature on each cancer in 2016–2021. The main goal is to systematically examine the cancer diagnosis systems for multi-organs of the human body as mentioned. Our critical survey analysis reveals that greater than 70% of deep learning researchers attain promising results with CNN-based approaches for the early diagnosis of multi-organ cancer. This survey includes the extensive discussion part along with current research challenges, possible solutions, and prospects. This research will endow novice researchers with valuable information to deepen their knowledge and also provide the room to develop new robust computer-aid diagnosis systems, which assist health professionals in bridging the gap between rapid diagnosis and treatment planning for cancer patients. [ABSTRACT FROM AUTHOR]

Highlights: [•] DNA is the molecular target for many anticancer drugs. [•] Drug–DNA interaction. [•] Various types of Drug–DNA interaction. [•] Various techniques used for the study of Drug–DNA interaction. [Copyright &y& Elsevier]

Abstract: A new series of organotin(IV) carboxylates [Me2SnL2] (1), [Bu2SnL2] (2), [Oct2SnL2] (3), [Me3SnL] (4), [Bu3SnL] (5) and [Ph3SnL] (6), where L=3-(2-fluorophenyl)-2-methylacrylate have been synthesized and characterized by FT-IR, CHNS and NMR (1H, 13C). The crystal structures of complexes (1) and (4) were also analyzed by single crystal X-ray analysis. The complex (1) adopted distorted octahedral geometry while complex (4) exhibited distorted trigonal bipyramidal geometry. The catalytic activity of the complexes was assessed in the production of biodiesel. Biodiesel is the monoalkyl ester of long chain fatty acids derived from the renewable feed stock, such as vegetable oil and is produced by a transesterification of vegetable oil with methanol. The results revealed that triorganotin(IV) complexes showed better catalytic activity than their diorganotin(IV) analogues. The complexes were also screened for their biological activities such as antibacterial, antifungal and cytotoxicity. The complexes 4–6 showed significant activity than the complexes 1–3. DNA interactions studies of ligand and complexes were investigated by UV–Vis absorption spectroscopy. The results showed that both ligand and complexes interact with DNA via intercalation as well as minor groove binding. [Copyright &y& Elsevier]

Abstract: Two new dinuclear copper(II) complexes 1 and 2, viz., [pyCu(μ2-OOCCH2C6H4R)4Cupy] where R= para-NO2(1) and para-CH3(2) and py=pyridine, have been synthesized and characterized using FT-IR, single crystal XRD and electrochemical solution studies. In both complexes, the two copper centers are linked by four carboxylate ligands in bridging bidentate bonding fashion. Each copper(II) ion is penta-coordinated with distorted square pyramidal geometry. Both complexes have typical paddlewheel structures with the apical positions occupied by pyridine molecules. The electrochemical behavior of the complexes was investigated by cyclic voltammetry in which the complexes gave rise to metal centered single electron irreversible electro-activity, corresponding to Cu(II)/Cu(III) oxidation and Cu(II)/Cu(I) reduction processes. A reduction wave in relatively higher negative potential range (−1.3 to −1.4V) was observed for the nitro group of complex 1. From the slope value of log i versus −log v, the redox processes were found predominantly diffusion controlled. The order of diffusion coefficient and heterogeneous rate constant for oxidation is: 1 > 2 owing to the more stable redox products in case of 1 while for reduction the order is: 2 > 1 due to overriding solvent effects and the larger molecular mass of 1 compared to 2. The charge transfer coefficient was also calculated and found typical of the irreversible redox processes. [Copyright &y& Elsevier]

Organotin(lV) complexes are known for their outstanding structural diversity and applications. Organotin(IV) carboxylates and dithiocarboxylates form an important class of organotin(IV) compounds. The structural diversity of these compounds emanates from several features including flexibility in coordination geometries, coordination numbers, and versatility of the ligands to engage in different modes of chelation from monodentate to bidentate. Triorganotin(IV) complexes with various ligands mostly demonstrate tetrahedral or trigonal bipyramidal symmetry with some distortions, while diorganotin(lV) and chlorodiorganotin(IV) complexes have variation of geometries and coordination numbers. Some monoorganotin(IV) complexes have also been reported with pentagonal bipyramidal geometries. [ABSTRACT FROM AUTHOR]

Methanol extracts of the roots of B. brevissima and B. parkeriana were examined for antidiabetic and antimicrobial activities. Six compounds i.e berberine, 8- oxo-berberine, dehydrocheilanthifoline, columbamine, jatrorrhizine and glutamic acid were isolated from the active fractions of these species for the first time. The antidiabetic activity was determined against Protein Tyrosine Phosphatase 1B (PTP 1B), a negative insulin regulator while the antimicrobial activity was performed against four bacterial strains: Mycobacterium marinum ATCC BAA535, sporadic Methicillin Resistant Staphylococcus aureus (SMRSA), endemic Methicillin Resistant Staphylococcus aureus (EMRSA) and Escherichia coli ATCC.8739 at different concentrations. Amongst the isolated compounds 8-oxo-berberine was found to be the most active antidiabetic (29 % of the positive control) while jatrorrhizine was the most active and selective antimicrobial against SMRSA and EMRSA (-1.2 % of the DMSO (D) control). [ABSTRACT FROM AUTHOR]

A novel polymeric complex has been synthesized by refluxing disodium acetylene dicarboxylate with tributyltin chloride in dry methanol. The solid-state structure of the complex has been determined by single-crystal X-ray analysis. The tin(IV) metal exhibits distorted trigonal bipyramidal geometry. Each carboxylate group of the ligand acts in a bidentate fashion, linking adjacent metal atoms to produce polymeric chains, which are cross-linked into a three-dimensional network. [ABSTRACT FROM AUTHOR]

The Schiff base has been synthesized by reacting tranexamic acid with indol-3-carboxyaldehyde in the first step and then with carbon disulfide at room temperature in the second step. The homobimetallic complexes have been synthesized by reaction of Schiff base with R2SnCl2 and R3SnCl in 1 :2M ratio under stirring, where R=methyl, n-butyl and phenyl. The ligand and complexes have been characterized by elemental analysis, FT-IR, multinuclear NMR (1H, 13C and 119Sn) and semiempirical study. IR data reveal the bidentate nature of the ligand. Five- or six-coordinate geometry was confirmed in solution by NMR spectroscopy. The homobimetallic complexes and ligand were tested in vitro against some pathogenic bacteria and fungi to assess their antimicrobial properties. The complexes show biological activities with few exceptions. [ABSTRACT FROM AUTHOR]

Heterobimetallic complexes of Zn(II) and Sn(IV) with sarcosine have been synthesized at room temperature under stirring conditions by the reaction of sarcosine and zinc acetate in 2 : 1 molar ratio followed by the stepwise addition of CS2 and organotin(IV) halides, where R =Me, n-Bu, and Ph. The complexes were characterized by elemental analysis, FT-IR and NMR (¹H, 13C) spectroscopy. IR data showed that the ligand acts in a bidentate manner. NMR data revealed the four coordinate geometry in solution state. In vitro antimicrobial activities data showed that complexes (3) and (4) were effective against bacterial and fungal strains with few exceptions. [ABSTRACT FROM AUTHOR]

Abstract: Four new organotin(IV) compounds [Me3SnL] (1), {[Me2SnL]2O}2 (2), Bu2SnL2 (3) and [Bu3SnL] (4), where L = O2C(C2H5)CCHC6H4F have been synthesized by refluxing the corresponding organotin(IV) chlorides with sodium (E)-2-(2-fluorobenzylidene) butanoate (NaL) in dry toluene except 2 for which Me2SnO was refluxed with (E)-2-(2-fluorobenzylidene) butanoic acid (LH) in the same solvent. NaL and all the compounds were characterized by FT-IR, 1H NMR and 13C NMR spectroscopy. NaL and compounds 1 and 2 were also characterized by X-ray single crystal analysis which confirmed a linear polymeric structure for compound 1 and a stannoxane for 2. The structural analyses have shown a bridging behavior of the ligand in trimethyl- and tributyl-, chelating as well as bridging behavior in dimethyl- and a chelating bidentate mode of coordination in dibutyltin(IV) compound which is also confirmed from the crystal analysis for compounds 1 and 2. Cyclic voltammetry was used to evaluate the electrochemical, kinetic and thermodynamic parameters for the electron transfer processes of compounds 1–4. Predominantly adsorption controlled redox processes were exhibited by the slope of log i p vs. −log v plots. The values of the diffusion coefficient (D o) indicated the role of solvent in the mobility of the electro-active species to some extent but the overall rate of the redox process was typical of the adsorption controlled process and could not be explained on the basis of solvation effects. The values of formal potential and charge transfer coefficient were also calculated. [Copyright &y& Elsevier]

The 'user-friendliness' of a website indicates to what extent it is easy for all intended users to interact with website to perform their required task(s). Given the explosive growth in the use of computerized systems as well as the World Wide Web for delivering information and services, usability/accessibility becomes an important issue. The purpose of this research is to study the available literature on usability/accessibility ready websites and their tools and guidelines. The research findings will help web engineers to build websites and web services accessible for all the target audience, including people with special needs. People with special needs meet barriers of all types, but computing technology is helping them to overcome these barriers. Accordingly, a great amount of development work has been carried out in the area of designing websites for disabled people, and it is increasingly becoming an important focus for a variety of reasons, legal (due to recent legislation in many countries promoting the rights of disabled people), economic, or ethical. Web engineers are increasingly aware that they need to ensure the usability of mainstream systems for disabled people by developing systems explicitly to meet the needs of disabled users (often referred to as assistive technologies), which also require evaluation to ensure their usability for the target audience. A descriptive/interpretive research method was used for the study of usability, accessibility, globalization, readability and culture differences based on related literatures and on previous studies by academics and industrial institutions. [ABSTRACT FROM AUTHOR]

Abstract: Biofuel has got tremendous attraction for the last decade as an alternative source of energy. Bioethanol and biodiesel are two main products of first generation biofuel. Biodiesel is chemically fatty acid methyl esters prepared from various edible and non-edible oils. It has been used as a substitute to mineral diesel during the last decade. This review is about generation, transesterification, factors affecting transesterification, catalysts (homogeneous and heterogeneous) and physico-chemical characterization of biodiesel by chromatographic and spectroscopic techniques. The alkaline homogeneous catalysts (NaOH or KOH) have been used on commercial scale for production of biodiesel because these are cheap and reaction occurs in less time. The heterogeneous catalysts such as metal oxides, e.g., CaO, MgO, SrO, ZnO, La2O3, Mg–Al hydrolalcite have been used for transesterification of vegetable oil due to their easy separation and reuse but these catalysts take more time for completion of reaction. The yield of biodiesel may be affected by alcohol/oil ratio, concentration of catalyst, time required for reaction, temperature free fatty acid moisture. The prepared biodiesel has been characterized by chromatographic techniques like gas chromatography, gas chromatography–mass spectroscopy, high performance liquid chromatography and spectroscopic techniques like nuclear magnetic resonance and infrared spectroscopy. [Copyright &y& Elsevier]

Abstract: The novel azomethine, 3-((3,5-dimethylphenylimino)methyl)benzene-1,2-diol (HL) was synthesized and characterized by elemental analysis, FT-IR, 1H, 13C NMR spectroscopy and single crystal analysis. The title compound has been screened for its biological activities including enzymatic study, antibacterial, antifungal, cytotoxicity, antioxidant and interaction with CTDNA, and showed remarkable activities in each area of research. The titled compound interacts with DNA via two binding modes: intercalation and groove binding. In intercalation the compound inserts itself into the base pairs of DNA and the compound–DNA complex is stabilized by π–π stacking. Interaction via groove binding may be due to hydrogen bonding to bases, typically to N3 of adenine and O2 of thymine. The synthesized compound was also found to be an effective antioxidant of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) and gives percent inhibition (%I) of 90.7 at a concentration level of 31.3μg/mL. [Copyright &y& Elsevier]

Authentication protocols are often used in smart grids to deliver the necessary level of security. A huge number of clients in such a system, however, provides the attacker with the ability to clone them, for example. Device fingerprints, or Physically Unclonable Functions (PUF), have been investigated as an authentication feature to thwart such attacks. In order to accomplish the necessary security in smart grid neighborhood area network communications and to prevent unwanted physical access to smart meters, a former study designed a lightweight authentication system in this way. The suggested protocol uses PUFs to reduce physical attacks. As a consequence, the server/meter impersonation attack is one of the many assaults that this protocol is thought to be secure against. On the other hand, it is generally acknowledged that no security solution should be trusted unless its security has been verified by independent researchers. As a result, this paper assesses the security of this protocol against a typical adversary who has access to or influences over the messages carried over the public channel. This study demonstrates that the attacker is simply capable of impersonating the server for the meter and vice versa. In addition, the suggested attacks desynchronize them, making the adversary the only one capable of interacting with the meter in the role of the legal server rather than the latter. Each of the proposed attacks is extremely effective, and their success probability is almost 1. Finally, a modification is suggested that successfully fixes the protocol's security weaknesses. The security proof of the improved protocol has been done through the Scyther tool. The computational cost comparison shows that the overhead of the proposed protocol compared to the former scheme is 4.85%, while it withstands various attacks, including traceability, desynchronization, impersonation, man-in-the-middle, and secret disclosure attacks. [ABSTRACT FROM AUTHOR]

Radio Frequency Identification (RFID) technology is a critical part of many Internet of Things (IoT) systems, including Medical IoT (MIoT) for instance. On the other hand, the IoT devices' numerous limitations (such as memory space, computing capability, and battery capacity) make it difficult to implement cost- and energy-efficient security solutions. As a result, several researchers attempted to address this problem, and several RFID-based security mechanisms for the MIoT and other constrained environments were proposed. In this vein, Wang et al. and Shariq et al. recently proposed CRUSAP and ESRAS ultra-lightweight authentication schemes. They demonstrated, both formally and informally, that their schemes meet the required security properties for RFID systems. In their proposed protocols, they have used a very lightweight operation called C r o (·) and R a n k (·) , respectively. However, in this paper, we show that those functions are not secure enough to provide the desired security. We show that C r o (·) is linear and reversible, and it is easy to obtain the secret values used in its calculation. Then, by exploiting the vulnerability of the C r o (·) function, we demonstrated that CRUSAP is vulnerable to secret disclosure attacks. The proposed attack has a success probability of "1" and is as simple as a CRUSAP protocol run. Other security attacks are obviously possible by obtaining the secret values of the tag and reader. In addition, we present a de-synchronization attack on the CRUSAP protocol. Furthermore, we provide a thorough examination of ESRAS and its R a n k (·) function. We first present a de-synchronization attack that works for any desired R a n k (·) function, including Shariq et al.'s proposed R a n k (·) function. We also show that R a n k (·) does not provide the desired confusion and diffusion that is claimed by the designers. Finally, we conduct a secret disclosure attack against ESRAS. [ABSTRACT FROM AUTHOR]

Abstract: Novel azomethine adducts of Sn(IV) have been synthesized by the reaction of R n SnCl4− n (n =1–3, R=CH3, n-C4H9, C6H5, C6H11) with 2-((3,5-dimethylphenylimino)methyl)phenol (HL). The products were characterized by elemental analysis, FT-IR, 1H, 13C and 119Sn NMR spectroscopy. Triphenyltin(IV) chloride [2-((3,5-dimethylphenylimino)methyl)phenol] (3) was also characterized by single crystal analysis. Spectroscopic and crystal data suggest that in all the complexes the ligand acts as a monodentate neutral molecule and is coordinated through oxygen to the tin atom forming pentacoordinated tin species. The phenolic hydrogen within the ligand is transferred to the imine nitrogen atom due to the coordination of oxygen with tin after complex formation. The ligand and its complexes have been screened for their biological activities, including DNA interaction, enzymatic, antibacterial, antifungal and cytotoxicity studies. Moreover, the electrochemical behavior of the synthesized compounds was also studied and the results obtained evidenced their irreversible oxidation. [Copyright &y& Elsevier]

Homobimetallic carboxylates with general formulae (R3Sn)2 L (where R = Me, n‐Bu, Ph and L = acetylene dicarboxylate dianion) have been synthesized by refluxing disodium salt of acetylene dicarboxylic acid with triorganotin chlorides in 1 : 2 (L : M) molar ratio in methanol under reflux. These complexes have been characterized by elemental analyses, FTIR, and multinuclear NMR (1H, 13C) spectroscopies. DFT calculations have been performed for structural elucidation and results were compared with semi‐empirical data. FTIR data indicate bidentate chelation of the ligand with tin and the complexes exhibit five‐coordinate geometry in the solid state. Such coordination behavior is also supported by DFT and semi‐empirical studies. NMR data confirm four‐coordinate geometry in solution. [ABSTRACT FROM PUBLISHER]