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The present investigation describes the use of bioadsorbent, ozonolysis, and integrated process (ozone integrated with bioadsorbent) treatment for leather industrial dye (Acid Yellow 2GL) removal from simulated wastewater. The morphological characterization of agriculturally based, chemically activated bioadsorbent was presented using SEM, FTIR, XRD, and BET analysis which suggested the high potential of the adsorbent for the removal from leather industry effluent. Maximum Acid Yellow 2GL removal of 98.3 ± 2.3% by integrated treatment was achieved at 30 min, bioadsorbent dose of 3 g/L and pH 7.5. Adsorption isotherms and kinetic models were measured for the validation of bioadsorption process for removal of dye. Langmuir’s isotherm was best fitted for Acid Yellow 2GL dye sorption in comparison to Freundlich isotherm. The phytotoxicity analysis of treated effluent ensured that the integrated process could be a prospective candidature for the treatment of dyeing effluent from the leather industry.

The present study was focused on the synthesis of brinjal waste activated carbon (BWAC) from the dry woody part of brinjal plant by chemical activation method. The BWAC was used as adsorbent to remove acid yellow 17 (AY-17) from the synthetic solution. For BWAC synthesis, phosphoric acid was used as a chemical reagent for chemical activation at a ratio of 1:1, followed by pyrolysis of chemically treated biomass in N2 atmosphere at high temperatures in a vertical reactor for improved chemical and surface properties of BWAC. The BWAC was characterized by several techniques such as BET surface area, pore distribution, SEM, FTIR, XRD, and point of zero charge (pHPZC). Various affecting parameters such as equilibrium time, initial pH, BWAC dose, AY-17 concentrations, and temperature for dye removal by BWAC were also investigated in the batch experiment. The maximum of 99.58% removal of AY-17 dye by BWAC occurred at pH 3. More than 97% dye was removed by BWAC from aqueous solution for initial 15 mg/L AY-17 dye concentration with other conditions such as 2 g/L dose, 5.00 ± 0.2 pH, 80 min equilibrium time, and 25 °C temperature. Therefore, further experiments were carried out at pH 5. Equilibrium data were fitted with the isotherm models such as Langmuir, Freundlich, and Temkin, and according to the correlation coefficient (R2), the Langmuir model was best fitted among them. The experimental kinetic data was well-validated with the pseudo-second-order kinetic model. The mass transfer studies of the dye onto BWAC were described by three models, such as Weber-Morris (intra-particle diffusion), Banghum’s, and liquid film diffusion models, and the result reported that all steps were involved for the adsorption process. The order for the rate-determining step, according to R2, was intra-particle diffusion > Bangham’s model > liquid film diffusion model. Recovery and recycling of dye-treated BWAC with desorption efficiency of ~ 73% was possible by 1 M NaOH treatment after 5th cycles. The simulated dye solution after treatment by BWAC was used in seed germination for toxicity assessment.

Here, we report a facile and easily scalable hydrothermal synthetic strategy to synthesize Ni–V layered double hydroxide (NiV LDH) nanosheets toward high-energy and high-power-density supercapacitor applications. NiV LDH nanosheets with varying Ni-to-V ratios were prepared. Three-dimensional curved nanosheets of Ni0.80V0.20 LDH showed better electrochemical performance compared to other synthesized NiV LDHs. The electrode coated with Ni0.80V0.20 LDH nanosheets in a three-electrode cell configuration showed excellent pseudocapacitive behavior, having a high specific capacity of 711 C g–1 (1581 F g–1) at a current density of 1 A g–1 in 2 M KOH. The material showed an excellent rate capability and retained the high specific capacity of 549 C g–1 (1220 F g–1) at a current density of 10 A g–1 and low internal resistances. Owing to its superior performance, Ni0.80V0.20 LDH nanosheets were used as positive electrode and commercial activated carbon was used as negative electrode for constructing a hybrid supercapacitor (HSC) device, having a working voltage of 1.5 V. The HSC device exhibited a high specific capacitance of 98 F g–1 at a current density of 1 A g–1. The HSC device showed a higher energy density of 30.6 Wh kg–1 at a power density of 0.78 kW kg–1 and maintained a high value of 24 Wh kg–1 when the power density was increased to 11.1 kW kg–1. The performance of NiV LDHs nanosheets indicates their great potential as low-cost electrode material for future energy-storage devices.

This study reports the synthesis of ultrathin Ni–V layered double hydroxide nanosheets on carbon cloth (NVL@CC) through adopting a facile and cost-effective method for flexible supercapacitor applications. The as-synthesized NVL@CC possesses a uniform, mechanically strong and highly ordered porous network with connected pores, ensuring high specific capacitance and enhanced cyclability. A high specific capacity of 1226 C g−1 (2790 F g−1) was obtained at 1 A g−1, and it remained at 430 C g−1 (1122 F g−1) even at a higher current density of 10 A g−1. A hybrid supercapacitor (HSC) was assembled with the NVL@CC electrode as the positive electrode and activated carbon coated carbon cloth as the negative electrode (NVL@CC//AC HSC). The devices showed an excellent energy density of 0.69 mW h cm−3 at a power density of 2.5 mW cm−3 with 100% of the original capacitance being retained at a current density of 5 mA cm−2. Furthermore, the devices exhibited an energy density of 0.24 mW h cm−3 even at a higher power density of 214.4 mW cm−3, surpassing the performances observed for many recently reported flexible supercapacitors. Importantly, the electrochemical performance of the solid-state flexible supercapacitors showed a negligible change upon bending and twisting of the devices. The devices showed no decay in specific capacitance and coulombic efficiency up to 5000 charge–discharge cycles, confirming the excellent cycle life of the HSC device. The performance of NVL@CC indicates the great potential of the material for future flexible energy storage devices.

Ekta Gupta,1 Manish Chandra Choudhary,2 Nimisha Upadhyay,1 Gaurav Singh,1 Suman Lata Nayak,3 Manoj Kumar,4 Shiv Kumar Sarin4 1Department of Clinical Virology, ILBS, New Delhi, India; 2Department of Molecular and Cellular Medicine, ILBS, New Delhi, India; 3Department of Nephrology, ILBS, New Delhi, India; 4Department of Hepatology, ILBS, New Delhi, IndiaCorrespondence: Ekta GuptaDepartment of Clinical Virology, Institute of Liver & Biliary Sciences, New Delhi 110070, IndiaEmail ektagaurisha@gmail.comPurpose: Baseline viral load and existence of resistance-associated substitutions (RASs) are associated with direct-acting antiviral agent (DAA) treatment failure in patients with chronic hepatitis C virus (HCV) infection.Patients and methods: This study was done on HCV-infected patients with different clinical conditions, group 1 included HCV-infected patients with only liver disease (n= 24) and group 2 had HCV-infected patients with coexisting chronic kidney disease (CKD) (n =26). Baseline RAS in the viral genome, before treatment initiation, was examined in both the groups to understand the host disease status on their occurrence.Results: Predominant genotype (gt) differed in both the groups, in group 1 it was gt3 while it was gt1 in group 2. Overall, the occurrence of RASs at baseline was seen in 10 patients (20%); in group 1 it was seen in 8 (33.3%) as compared to only 2 (7.6%) in group 2; p < 0.001. RAS in both NS5a and NS5b regions of the virus was seen in group 1 while in group 2, RASs were seen only in the NS5a region of the virus at 30K position. In group 1, multiple RASs were also seen. The existence of RAS at baseline in both the groups did not affect the attainment of post-treatment cure for the virus in terms of sustained virological response (SVR).Conclusion: Host disease status influences the occurrence of baseline RAS in the virus.Keywords: Hepatitis C Virus infection, drug resistance, direct-acting antivirals

Background: Hepatitis B-X Protein (HBx) encoded in Hepatitis B virus (HBV) is known to play a critical role in development and progression of HBV induced hepatocellular carcinoma (HCC). HBx interacts with and activates various cells in HCC microenvironment to promote tumor initiation, progression and invasion. In this study, we investigated how surrounding stromal cells interact with HBx-infected hepatoma cells by a series of in vitro co-culture studies. Methods: Huh7 hepatoma cells were cultured and transfected with the mammalian expression vector pGFP-HBx. Co-culture assays were performed between HBx-transfected Huh7 cells and conditioned media (CM) from stromal cells [endothelial cell lines (HUVECs) and hepatic stellate cell lines (LX2 cells)]. The effect of these interactions was studied by a series of functional assays like chemotaxis, invasion, and wound healing scratch assays. Also, quantitative real time (RT)-PCRs of the mesenchymal genes was performed in the hepatoma cells with and without the co-cultures. Hep3B cells with an integrated HBV genome were taken as positive controls. Results: HBx-transfected Huh7 cells cultured in presence of CM from HUVECs illustrated enhanced migration and tube formation as compared to HBx-transfected cells cultured alone or co-cultured with LX2 cells. HBx-transfected hepatoma cells incubated with CM from HUVECs also expressed mesenchymal genes including Thy1, CDH2, TGFβR1, VIM, and CD133. ELISAs revealed increased levels of TGF-β in CM from HUVECs. In comparison to unstimulated HBx-transfected Huh7 cells, TGF-β stimulated cells displayed increased invasive properties and mesenchymal gene expression. RT-PCR and flow cytometry analysis further demonstrated that incubation with either CM from HUVECs or TGF-β significantly increased the expression of a stemness marker, CD133 in HBx-infected hepatoma cells. Gene inhibition experiments with CD133 siRNA showed a downregulation of mesenchymal gene expression and properties in TGF-β induced HBx-infected hepatoma cells as compared to that observed in control siRNA treated cells, indicating CD133 as one of the key molecules affecting epithelial to mesenchymal transition (EMT) in HBx-infected cells. Conclusion: The study indicates that secretory factors like TGF-β from neighboring endothelial cells may enhance expression of CD133 and impart an aggressive EMT phenotype to HBx-infected hepatoma cells in HBV induced HCC.

The nuclear reactors operating worldwide are currently using the uranium mined from the resources available on the earth's crust. A significant volume of aqueous waste containing a small quantity of uranium was generated during the processing of ores. There is a growing demand to remove this toxic uranium from these aqueous streams, owing to the limit of tolerable daily intake (15 μg L−1) for uranium imposed by the World Health Organization. This demand throws huge challenges to the separation chemists to engineer the solid phase adsorbents having high capacity, excellent selectivity and satisfactory throughputs for processing a vast quantity of aqueous waste containing traces of uranium. In this context, the task specific amidic succinic acid (SUC) functional groups tailored on mesoporous silica having wide porosity and large surface area have been prepared and characterized by BET surface area, pore and particle size distribution, thermogravimetry, SEM-EDX analysis, FT-IR and Raman spectroscopy. The adsorption behavior of uranium (VI) from the aqueous phase on the tailored adsorbent (MCM-SUC) was studied as a function of pH of the aqueous phase, duration of equilibration, uranium concentration in the aqueous phase, and the results were compared with the adsorbent containing the same functional group but grafted on silica gel (Si-SUC), which exhibited adsorption capacity of 61 mg g−1. The fast kinetics of adsorption and significantly high Langmuir adsorption capacity of uranium (807 mgg −1), as compared to the other mesoporous adsorbents reported in literature, achieved in MCM-SUC was due to controlled synthesis of SUC functionalized mesoporous silica that favoured high degree of SUC number density on the mesoporous material. The adsorbed uranium was recovered using 0.1 M nitric acid.

Every leather industry produces a large quantity of wastewater having enormous amount of pollutants which have a deleterious effect on the environment drastically if it is discharged without appropriate treatment. The tanning processes are responsible for the discharge of uncontrolled COD, BOD, TDS, Cr (III), chlorides, sulphates, and other heavy metals. This study provides a review of the treatment of leather wastewater involving physical treatment, electrocoagulation, adsorption, chemical precipitation, ozonation, electro-oxidation, photocatalytic ozonation, Fenton oxidation, biochemical/biological treatment, and hybrid treatment processes. It is clear from the study of some other papers that chemical or biological treatment followed by membrane separation has the potential capability to remove the harmful contaminants from tannery wastewater. Researchers also reported that the tannery industrial solid waste used after removal of chromium has a good amount of minerals (P and K) which can be further used for several purposes including as fertiliser.

Processing of uranium ore for the production of reactor-grade uranium results in the generation of large amount of aqueous waste containing small quantities of uranium, but higher than the guideline value (15 μg L−1) recommended by World Health Organization (WHO). The presence of uranium in aqueous waste poses several hazards and environmental issues due to the radioactive nature and migration behavior of uranium in the geosphere. In order to remove uranium (VI) from aqueous waste, the diethylenetriamine modified high capacity magnetic iron oxide adsorbent, abbreviated as Fe-DETA, was prepared and studied for the extraction of uranium from aqueous solutions. The Fe-DETA was characterized by X-ray diffraction, thermal analysis, infrared and Raman spectroscopy, and scanning electron microscopy. Significantly high amount (2 mmol g−1) of diethylenetriamine functional group (DETA) was anchored on magnetic iron oxide particles. The extraction of U(VI) from aqueous phase was studied as a function of pH of the aqueous phase, duration of the contact between Fe-DETA and aqueous phase, concentration of U(VI) in aqueous solution etc. The data on the rate of extraction of U(VI) in Fe-DETA was fitted into the first order and second order rate equations. The apparent uranium extraction capacity on Fe-DETA was determined to be 236 mg g−1, which correspond to the formation of 1:2 complex of U(VI) to diethylenetriamine ligand in Fe-DETA phase. The loaded U(VI) in Fe-DETA was quantitatively recovered using dilute Na2CO3 solution, and the recovered Fe-DETA was recycled for further extraction of U(VI), without any change in the apparent U(VI) extraction capacity.

The electrochemistry of Th 4+ ions was studied in LiCl-KCl eutectic in the temperature range 698–803 K and compared with literature data. Various transient electrochemical techniques like cyclic voltammetry, chronopotentiometry, square-wave voltammetry were used to determine diffusion co-efficient of Th 4+ and apparent standard electrode potential for Th 4+ /Th electrode process. The electrode kinetics of Th 4+ /Th couple was also investigated by convolution voltammetry and impedance spectroscopy. Based on the above studies, the reversibility of Th 4+ /Th couple was addressed. The feasibility of electrochemical separation of uranium and thorium in LiCl-KCl eutectic is also discussed in this paper. It was seen that the separation of U from Th matrix was difficult in molten LiCl-KCl using a solid rod cathode and suitable reactive electrodes need to be used for efficient separation.

Wavelength Modulation Spectroscopy (WMS) using tunable diode laser is a versatile method for determination of concentration, temperature and velocity of absorbing gaseous molecules. This technique finds major application in industrial and scientific areas. An important component of sensors/systems based on these techniques is the phase sensitive detection for demodulation, in the form of hardware or software based lock-in amplifier. This paper presents the details of (a) a MATLAB based Digital Lock-in amplifier technique for extraction of harmonics (1f & 2f), from the wavelength modulated optical absorption signal, and (b) a MATLAB based program for calculating the oxygen concentration from 1f and 2f harmonics. The oxygen concentration has been measured using MATLAB implemented digital lock-in-amplifier and concentration computation formula. The deviation in the measured Oxygen concentration from the actual Oxygen concentration supplied through the mass flow controllers is less than 1%. The oxygen concentration measured using digital Lock-in amplifier has a deviation within 0.2% as compared to measurement from hardware measuring device.

Electrochemical behavior of neodymium (III) ion was studied in LiCl-KCl eutectic melt in the temperature range 723-798 K on inert tungsten electrode using various transient electrochemical techniques such as cyclic voltammetry, convolution voltammetry, chronopotentiometry and square wave voltammetry. The reduction of Nd(III) ion to Nd metal on tungsten electrode takes place in two steps- Nd(III)/Nd(II) and Nd(II)/Nd(0). The diffusion coefficient of Nd(III) and Nd (II) ions were determined. Reduction of Nd(III) to Nd(II) showed reversible electrode behavior and that for Nd(II) to Nd metal followed the quasi-reversible behavior. Heterogeneous rate constant for the reduction, Nd(II)/Nd(0) was estimated from the convoluted voltammograms. The apparent standard electrode potentials, E N d ( I I I ) / N d ( I I ) * , E N d ( I I ) / N d ( 0 ) * and E N d ( I I I ) / N d ( 0 ) * were estimated from the cyclic voltammograms. The electrode behavior of Nd(III) ion on solid aluminium electrode and liquid cadmium electrode was studied by cyclic voltammetry. Under-potential reduction of Nd(III) ion takes place on Al and Cd cathodes in a single step with three electron transfer. The apparent standard electrode potentials, E N d ( I I I ) / N d ( A l ) * and E N d ( I I I ) / N d ( C d ) * were estimated for different temperatures in the range 698-773 K. The formation of intermetallics, Al 11 Nd 3 and Cd 11 Nd were studied from open circuit potential measurement on Al and Cd film electrode respectively. The Gibbs energy of formation for these intermetallics was evaluated. The activity of neodymium in Al/Cd, the excess Gibbs energy and the activity coefficient of neodymium in Al/Cd were estimated from the open circuit potential measurement. SEM-EDX analysis and the XRD pattern of the electro-deposit revealed the formation of Al 11 Nd 3 and Cd 11 Nd on Al and Cd cathodes respectively.

Electrochemical redox behaviour of Ce (III) ion in LiF–CaF 2 eutectic was studied at 1093 K using tungsten (inert) and nickel (reactive) as working electrodes and platinum as quasi-reference electrode by various electrochemical transient techniques viz. cyclic voltammetry (CV), square-wave voltammetry (SQWV) and chronopotentiometry (CP). It was deduced that reduction of Ce (III) to Ce metal occurs by a single step, three-electron transfer. Diffusion coefficient ( D Ce(III) ) of Ce (III) ion was determined from CV, semi-integral analysis and CP and the values obtained were 2.2 × 10 −5 , 5.4 × 10 −5 and 3.0 × 10 −5 cm 2 s −1 , respectively. Electrochemical studies in the presence of Ni electrode showed the formation of the inter-metallic compounds CeNi 5 and Ce 2 Ni 7 , which were characterized by powder X-ray diffraction and SEM-EDAX analysis.

The mixture of acaricides propargite+ hexythiazox resulted in more mortality of the chilli yellow mite Polyphagotarsonemus latus than their individual sprays. It also gave a higher % kill as compared to fenazaquin, fenpyroximate, and neem oil. With the first spray, propargite+ hexithiazox @ 567+27 a.i, there was maximum reduction in the life stages of P. latus (81.15%) compared to its other doses, other acaricides and also neem oil. Similarly, with second spray too its dose @ 567+27 a.i gave maximum mortality (82.73%), followed by its dose @ 525+25 a.i (76.18%).

Ruthenium complexes [(η 5 -C 5 H 5 )Ru(PPh 3 )(κ 2 -paa)]PF 6 (paa = pyridine-2-carbaldehyde azine) and [(η 5 -C 5 H 5 )Ru(κ 1 -dppm)(κ 2 -paa)]BF 4 [dppm = bis(diphenylphosphanyl)methane] have been employed as a synthon in the synthesis of homo/hetero bi-/trimetallic complexes. It is the uncoordinated N,N-donor site on paa in complex [(η 5 -C 5 H 5 )Ru(PPh 3 )(κ 2 -paa)]PF 6 , and N,N-donor site on paa and pendant phosphorus in [(η 5 -C 5 H 5 )Ru(κ 1 -dppm)(κ 2 -paa)]BF 4 that allows for their incorporation into bi-/trimetallic systems. The resulting complexes have been characterized by analytical, spectral and electrochemical studies. Molecular structures of homo-bimetallic complex [(PPh 3 )(η 5 -C 5 H 5 )Ru(μ-paa)Ru(η 6 -C 10 H 14 )Cl](PF 6 ) 2 and hetero-bimetallic complex [(PPh 3 )(η 5 -C 5 H 5 )Ru(μ-paa)Rh(η 5 -C 5 Me 5 )Cl](PF 6 ) 2 have been authenticated crystallographically. Complexes exhibit absorptions throughout the visible region and complicated electrochemical behaviour. Metal-based Ru II /Ru III oxidations in the bimetallic complexes do not vary as in the trimetallic complexes.

Reaction of the ruthenium complexes [RuCl2(EPh3)3] (E = P, As), [(η5-C5H5)RuCl(EPh3)2] (E = P, As), [(η5-C5Me5)RuCl(PPh3)2] and [(η5-C9H7)RuCl(PPh3)2] with 2,6-diacetylpyridinemonoxime (dapmoH) have been investigated. Compounds with the formulations [Ru(κ3-dapmoH)Cl(PPh3)2]PF6 (1), [Ru(κ3-dapmoH)Cl(PPh3)2]BF4 (2) and [Ru(κ3-dapmoH)Cl(AsPh3)2]Cl (3) have been isolated and fully characterized by elemental analyses, IR, NMR, electronic, emission spectral and electrochemical studies. Molecular structures of the complexes [ Ru ( κ 3 -dapmoH ) Cl ( PPh 3 ) 2 ] PF 6 · H 2 O (1) and [ Ru ( κ 3 -dapmoH ) Cl ( PPh 3 ) 2 ] BF 4 · 1.5 H 2 O (2) have been determined by single crystal X-ray diffraction studies. A structural feature of interest for both the compounds is that the counter anions in 1 and 2 play vital role in the self-assembly of cages through intermolecular weak interactions in which water dimers or trimers are encapsulated. Compounds 1 and 2 strongly emit upon excitation at their respective MLCT transitions.

Ammonia–borane, NH3BH3, dissolves in water to form a stable solution, to which the addition of a catalytic amount of suitable metal catalysts leads to hydrogen release with an H2 to NH3BH3 ratio up to 3.0, corresponding to 8.9 wt.% of the starting materials NH3BH3 and H2O. This article presents a brief overview of the hydrogen generation system based on the catalytic dissociation and hydrolysis of ammonia–borane, which possesses high potential to find application to portable fuel cells.

Ammonia-borane (NH 3 BH 3 ), as a source of protide (H − ), is initially proposed to release its energy through a fuel cell (direct ammonia-borane fuel cell, DABFC). Cell performance has been elucidated in a 25 cm 2 laboratory cell constructed with an oxygen cathode and an ammonia-borane solution fed anode, where the catalyst layers are made of Vulcan XC-72 with 30 wt.% Pt. The potential is 0.6 V at the current density of 24 mA cm −2 , corresponding to power density >14 mW cm −2 at room temperature. The direct electron transfer from protide (H − ) in NH 3 BH 3 to proton (H + ) has been further proved by the open circuit potential and the cyclic voltammetry results, which show the possibility of improvement in the performance of DABFC by, for example, exploring new electrode materials.

Nano-clusters of noble metals Ru, Rh, Pd, Pt and Au have been supported on γ-Al 2 O 3 , C and SiO 2 , of which the catalytic activities have been investigated for hydrolysis of NH 3 BH 3 . Among these catalysts, the Ru, Rh and Pt catalysts exhibit high activities to generate stoichiometric amount of hydrogen with fast kinetics, whereas the Pd and Au catalysts are less active. Support effect has been studied by testing the hydrogen generation reaction in the presence of Pt supported on γ-Al 2 O 3 , VULCAN ® carbon and SiO 2 , and it is found that Pt on γ-Al 2 O 3 , which has the smallest particle size, is the most active. Concentration dependence of the hydrogen generation from aqueous NH 3 BH 3 solutions has been investigated in the presence of Pt/γ-Al 2 O 3 by keeping the amount of Pt/γ-Al 2 O 3 catalyst unchanged, which exhibits that the hydrogen release versus time (ml H 2 min −1 ) does not significantly change with increasing the NH 3 BH 3 concentration, indicating that the hydrogen release rate is not dependent on the NH 3 BH 3 concentration and the high activity of the Pt catalyst can be kept at high NH 3 BH 3 concentrations. Activation energies have been measured to be 23, 21 and 21 kJ mol −1 for Ru/γ-Al 2 O 3 , Rh/γ-Al 2 O 3 and Pt/γ-Al 2 O 3 catalysts, respectively, which may correspond to the step of B–N bond breaking on the metal surfaces. The particle sizes, surface morphology and surface areas of the catalysts have been obtained by TEM and BET experiments.

We have studied catalytic performance of supported non-noble metals for hydrogen generation from aqueous NH3BH3 at room temperature. Among the tested non-noble metals, supported Co, Ni and Cu are the most catalytically active, with which hydrogen is released with an almost stoichiometric amount from aqueous NH3BH3, whereas supported Fe is catalytically inactive for this reaction. Support effects on the catalytic activity have been investigated by testing the hydrogen generation reaction in the presence of Co supported on γ-Al2O3, SiO2 and C and it is found that the Co/C catalyst has higher activity. Activation energy for hydrogen generation from aqueous NH3BH3 in the presence of Co/γ-Al2O3 was measured to be 62 kJ mol−1; this may correspond to the step of B N bond breaking. Particle size, surface morphology and surface area of the supported metal catalysts were examined by X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray (EDX) and BET experiments. It is found that with decreasing the particle size the activity of the supported catalyst is increased. The low-cost and high-performance supported non-noble metal catalysts may have high potential to find its application to the hydrogen generation for portable fuel cells.

Reactions of the chloro-bridged dimeric complexes [{(η5-C5Me5)M(μ-Cl)Cl}2] (M = Rh, Ir) with the polypyridyl ligands 2,3-di(2-pyridyl)pyrazine (dpp) and 2,4,6-tri(2-pyridyl)-1,3,5-triazine (tptz) in the presence of ammonium tetrafluoroborate gave the mononuclear complexes [(η5-C5Me5)MCl(κ2-dpp)]BF4 [M = Rh (1), Ir (2)] and [(η5-C5Me5)MCl(κ2-tptz)]BF4 [M = Rh (3), Ir (4)]. The complexes have been characterised by elemental analysis, FAB-MS, ESMS, IR, NMR, electronic and emission spectroscopic studies and the molecular structures of 1, 2 and 3 have been crystallographically determined. Structural studies on the complexes revealed the presence of helical superstructures resulting from C–H···X (X = N, F, Cl and π) interactions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Pure hydrogen generation under mild conditions in a controllable way is important for portable devices. Recently, we have found that an aq. ammonia-borane (NH3BH3) solution is a potential hydrogen source with noble metal catalysts. For practical use, the development of a low-cost, efficient and safe system is desired. In this study, we found that solid acids such as cation exchange resins and zeolites, which are low-cost and safe, also exhibit high activities for the dissociation and hydrolysis of NH3BH3 to generate hydrogen with an H2 to NH3BH3 ratio up to 3.0 at room temperature. The reaction rate depends on the type of solid acid. Especially, Dowex and Amberlyst, the two low-cost solid acids often used as catalysts in a variety of reactions, exhibit reaction kinetics higher than the noble metal catalysts. Carbon dioxide is also active as an acid for this reaction. The reaction products in solution have been identified by 11B NMR, and the evolved gases have been analyzed by mass spectrometry which indicates high purity hydrogen. This new system may have a high potential for application in fuel cells.

A high-performance hydrogen generation system based on transition metal-catalyzed dissociation and hydrolysis of ammonia–borane complex (NH3BH3) at room temperature has been achieved. NH3BH3 dissolves in water to form a solution stable in the absence of air. The addition of a catalytic amount of suitable metal catalysts such as Pt, Rh, and Pd into the solutions with various concentrations leads to rigorous release of hydrogen gas with an H2 to NH3BH3 ratio up to 3.0, corresponding to 8.9 wt.% of the starting materials NH3BH3 and H2O. The Pt catalysts are the most active and no significant deactivation was observed for the recycled catalysts. This new system possesses high potential to find its application to portable fuel cells.

New polypyridyl osmium(II) complexes [Os(κ 3 -tptz)(EPh 3 ) 2 Cl]BF 4 (E = P, 1 ; As, 2 ) with group 15 donor ligands are reported. Structural studies on the representative complex [Os(κ 3 -tptz)(PPh 3 ) 2 Cl]BF 4 revealed formation of helical racemates with sidewise stacking of right and left-handed anti-parallel helical strands. Salient structural features and DNA binding studies along with binding constant [6.6 × 10 3 M −1 ] and site size [0.12] of the complex 1 with calf thymus (ct) DNA by absorption spectroscopy are described.

Tetrafluoroborate salts of cationic ruthenium complexes [Ru(kappa(3)-tpy)(EPh(3))(2)Cl](+) (tpy=2,2':6',2''-terpyridine; E=P, 1 or As, 2) containing both the group 15 donor ligands and tpy and their representative substitution products are reported. Weak interaction {C-H...X (X=Cl, F and pi) and pi-pi interaction} studies revealed the presence of a double helical motif in complex 1, while the complex 2 assumes a single helical motif. Intercalative mode of interaction of the complexes 1 and 2 with calf thymus DNA (ctDNA) has been supported by absorption titration studies.

Reaction of the dimeric rhodium complex [{(η5-C5Me5)Rh(μ-Cl)Cl}2] with an excess of 1-(4-cyanophenyl)-imidazole in dichloromethane afforded neutral mononuclear complex [(η5-C5Me5)RhCl2(CPI)] (CPI = 1-(4-cyanophenyl)-imidazole) 1. The complex 1 reacted with EPh3 (E = P, As, Sb) and N–N donor bases 2,2′-bipyridine and 1,10-phenanthroline in different solvents to give substitution products wherein, nature of the product was governed by polarity of the solvents employed in the reaction. Resulting complexes have been characterized by elemental analyses, spectral (FAB-MS, IR, 1H,13C, 31P NMR, UV–Vis, Emission) and electrochemical studies. Coordination of CPI through imidazole nitrogen and the presence of pendant nitrile group have been supported by spectral studies.

New cationic complexes [Ru(η5-C5H5)(EPh3)(L)]BF4 [L = pyridine-2-carbaldehyde azine (paa); E = P, 1; E = As, 2; E = Sb, 3] and κ1 bonded dppm complexes [Ru(η5-C5H5)(κ1-dppm)(L)]BF4 [L = paa 4; L = p-phenylene-bis(picoline)aldimine (pbp) 5] containing both group V donor and pyridyl–azine ligand are reported. The complexes were fully characterized by analytical and spectral studies. 31P NMR spectral studies suggested coordination of dppm in the complexes 4 and 5 in κ1-manner, which was further, confirmed by structural studies on the representative complex 4. Weak interaction studies revealed that inter- and intramolecular C–H⋯X (X = O, F, Cl, π) and π–π interactions in the complexes 1 and 4 lead to helical structures.

Synthesis, structure, reactivity and enzyme inhibitory activity of the new cationic ruthenium complexes [Ru(κ3-L)(EPh3)2Cl]BF4 [L = 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz); E = P (1), As (2)] and their substitution products [Ru(κ3-tptz)(PPh3)(dtc)]Cl (3), [Ru(κ3-tptz)(PPh3)(CN)2] (4), [Ru(κ3-tptz)(AsPh3)(dtc)]BF4 (5), and [Ru(κ3-tptz)(AsPh3)(CN)2] (6) are reported. The complexes were characterized by analytical and spectroscopic methods and the structures of the complexes 1, 2 and 3 determined by X-ray diffraction studies. C−H···X (X = Cl, F and S), C−H···π and π−π interactions were observed in these complexes. Further studies indicated that the complexes [Ru(κ3-L)(EPh3)2Cl]+ could find application as precursors in the synthesis of other ruthenium complexes or as metallo-ligands. The complexes also interact with DNA, which was illustrated by absorption titration studies with CT-DNA and inhibition of topoisomerase II of the filarial parasite Setaria cervi. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

In search of new DNA probes a series of new mono and binuclear cationic complexes [RuH(CO)(PPh3)2(L)]+ and [RuH(CO)(PPh3)2(-μ-L)RuH(CO)(PPh3)2]2+ [L=pyridine-2-carbaldehyde azine (paa), p-phenylene-bis(picoline)aldimine (pbp) and p-biphenylene-bis(picoline)aldimine (bbp)] have been synthesized. The reaction products were characterized by microanalyses, spectral (IR, UV–Vis, NMR and ESMS and FAB-MS) and electrochemical studies. Structure of the representative mononuclear complex [RuH(CO)(PPh3)2(paa)]BF4 was crystallographically determined. The crystal packing in the complex [RuH(CO)(PPh3)2(paa)]BF4 is stabilized by intermolecular π–π stacking resulting into a spiral network. Topoisomerase II inhibitory activity of the complexes and a few other related complexes [RuH(CO)(PPh3)2(L)]+ {L=2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) and 2,3-bis(2-pyridyl)-pyrazine (bppz)} have been examined against filarial parasite Setaria cervi. Absorption titration experiments provided good support for DNA interaction and binding constants have also been calculated which were found in the range 1.2 × 103–4.01 × 104 M−1.

The synthesis and characterization of binuclear ruthenium complexes [{(η 6 -C 6 H 6 )Ru} 2 (μ-bsh) 2 ] ( 1 ), [{(η 6 -C 10 H 14 )Ru} 2 (μ-bsh) 2 ] ( 2 ), [{(η 6 -C 6 Me 6 )Ru} 2 (μ-bsh) 2 ] ( 3 ), and rhodium complex [{(η 5 -C 5 Me 5 )RhCl} 2 (μ-bsh)] ( 4 ) (bsh= N , N ′ -bis(salicylidine)-hydrazine dianion) are reported. The complexes have been fully characterized by analytical and spectral techniques and unusual coordination mode of the ligand H 2 bsh has been confirmed by single crystal X-ray analysis of the complex 2 . Structural data revealed extensive inter- and intra-molecular C–H⋯O and C–H⋯π interactions and involvement of methyl and isopropyl hydrogen from the p -cymene in hydrogen bonding.

New series of mono and binuclear arene ruthenium complexes [{(η 6 -arene)RuCl(L)}] + and [{(η 6 -arene)RuCl} 2 (μ-L) 2 ] 2 + (arene = benzene, p-cymene or hexamethylbenzene), {L = pyridine-2-carbaldehyde azine (paa), p-phenylene-bis(picoline)-aldimine (pbp) and p-bi-phenylene-bis(picoline)-aldimine (bbp)} are reported. The complexes have been fully characterized and molecular structure of the representative mononuclear complex [(η 6 -C 6 Me 6 )RuCl(paa)]BF 4 (1), binuclear complexes [{(η 6 -C 1 0 H 1 4 )RuCl} 2 (μ-paa)](BF 4 ) 2 (3) and [{(η 6 -C 1 0 H 1 4 )RuCl} 2 (μ-pbp)](BF 4 ) 2 (6) have been determined by single crystal X-ray diffraction analyses. Single crystal X-ray structure determination revealed that in the binuclear complexes the [(η 6 -C 1 0 H 1 4 )RuCl] + units are trans disposed. Further, the crystal packing in the complexes 1, 3 and 6 is stabilized by C-H...X type (X = Cl, F) inter, intramolecular hydrogen bonding and π-π stacking (3). To explore the ambiguous nature of the bonding between pyridine-2-carbaldehyde azine (paa) with ruthenium containing units [(η 6 -arene)RuCl] + , DFT/B3LYP calculations have been performed on the complexes [(η 6 -are-ne)RuCl(paa)] + (arene = C 6 H 6 , I; C 6 Me 6 , II; C 1 0 H 1 4 , III).

The reactions of [RuH(CO)Cl(PPh3)3] with N,N′-bis(salicylidine)-hydrazine (H2bsh) and N,N′-bis(salicylidine)-p-phenylene diammine (H2bsp) in presence of KOH in methanol led in the formation of neutral mononuclear complexes with the formulations [RuH(CO)(PPh3)2(L)] (LHbsh or Hbsp). These present the first examples where the ligands H2bsh or H2bsp provide only two of its available donor sites for interaction with the metal centre. The complexes have been characterized by elemental analyses, FAB-MS, IR, 1H, 13C, 31P NMR and electronic spectral studies. Molecular structure of the representative complex [RuH(CO)(PPh3)2(Hbsh)] have been determined by single crystal X-ray analysis.

Reactions of the poly-pyridyl bridging ligand 2,4,6-tris(2-pyridyl)-1,3,5-triazine; 2,3-bis(2-pyridyl)-pyrazine and 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (referred hereafter as tptz, bppz and bptz respectively) with [RuH(CO)Cl(PPh3)3] in methanol, gave highly stable cationic complexes with the formulation [RuH(CO)(PPh3)2(L)]+. Further, the mononuclear complex [RuH(CO)(PPh3)2(bppz)]PF6 reacted with K2PtCl4, [PdCl2(benzonitrile)2], [{Ru(η6-C10H14)(μ-Cl)Cl}2], [{Ru(η6-C6Me6)(μ-Cl)Cl}2], [RuCl(η5-C5H5)(PPh3)2] and [{Rh(η5-C5Me5)(μ-Cl)Cl}2] in methanol under refluxing conditions to give bppz bridged binuclear complexes with the formulation [RuH(CO)(PPh3)2(bppz)PtCl2]PF6, [RuH(CO)(PPh3)2(bppz)PdCl2]PF6, [RuH(CO)(PPh3)2(bppz)(η6-C10H14)RuCl](PF6)2, [RuH(CO)(PPh3)2(bppz)(η6-C6Me6)Cl2Ru](PF6)2, [RuH(CO)(PPh3)2(bppz)(η5-C5H5)(PPh3)Ru](PF6)2 and [RuH(CO)(PPh3)2(bppz)Rh(η5-C5Me5)Cl](PF6)2 in quantitative yield. The reaction products have been characterized by elemental analyses, IR, 1H-, 1H–1H-COSY, 13C-, 31P-NMR, ESMS, FAB mass spectroscopy, electronic spectra and cyclic voltammetry. Molecular structure of the representative mononuclear complex [RuH(CO)(PPh3)2(tptz)]BF4 has been confirmed by X-ray crystallography. Crystal structure determination revealed η2-coordination of the ligand tptz with the metal center. Crystal data: monoclinic, P21/n, a=17.810(6) A, b=22.233(9) A, c=12.156(4) A, β=90.06(3)°, Z=4, R=0.078.

Alkaline protease from Conidiobolus macrosporus was immobilized on polyamide using glutaraldehyde as a bifunctional agent. The immobilized enzyme was optimally active at a higher temperature of 50 °C than the free enzyme (40 °C ) and showed a ten-fold increased thermostability at 60 °C compared to that of the free enzyme. The efficiency of immobilization was 58% under the optimal conditions of pH and temperature. There was a 14-fold decrease in the K m of immobilized enzyme compared to the free enzyme. The immobilized enzyme was fully active even after twenty-two cycles of repeated use. It retained 80% activity at 50 °C in presence of 8 M urea exhibiting its stability to the denaturant and was compatible with several commercial detergents.

Three novel luminescent piano-stool arene ruthenium complexes of general formula [(eta(6)-arene)RuCl(2)(CPI)] (eta(6)-arene = benzene, 1, p-cymene, 2, and hexamethylbenzene, 3; CPI=1-(4-cyanophenyl)imidazole were prepared. The molecular structures of 2 and 3 were determined crystallographically. Reaction of 1-3 with EPh(3) (E = P, As, or Sb) and N-N donor bases such as 2,2'-bipyridine and 1,10-phenanthroline afforded cationic mononuclear complexes of general formula [(eta(6)-arene)RuCl(CPI)(EPh(3))](+) (eta(6)-arene = C(6)H(6), E = P (1a), E = As (1b), E = Sb(1c); eta(6)-arene = C(10)H(14), E = P (2a), E = As (2b), E = Sb (2c); eta(6)-arene = C(6)Me(6), E = P (3a), E = As (3b), E = Sb (3c)) and [(eta(6)-arene)Ru(N-N)(CPI)](2+) (eta(6)-arene = C(6)H(6), N-N = bipy (1d), N-N = phen (1e); eta(6)-arene = C(10)H(14), N-N = bipy (2d), N-N = phen (2e); eta(6)-arene = C(6)Me(6), N-N = bipy (3d), N-N = phen (3e)). Molecular structures of 1a and 2a were also confirmed by X-ray crystallography. Structural studies of the complexes 2, 3, 1a, and 2a supported coordination of CPI through the imidazole nitrogen and the presence of a pendant nitrile group. Structural data also revealed stabilization of crystal packing in the complexes 2, 3, and 2a by C-H...X (X = Cl, F) type inter- and intramolecular interactions and in complex 1a by pi-pi stacking. Moreover, neutral homonuclear bimetallic complexes 2f,g were prepared by using complex 2 as a metallo-ligand, where CPI acts as a bridge between two metal centers. Emission spectra of the mononuclear complexes [(eta(6)-arene)RuCl(2)(CPI)] and its derivatives exhibited intense luminescence when excited in the metal to ligand charge-transfer band.

The crystal structure of the neutral RuII complex [RuCl2(η6–C10H14)(C2H6OS)] is reported. The overall coordination geometry about the ruthenium centre is best described as a typical `piano stool'. In the p-cymene ligand, the six C atoms of the arene ring are in a planar configuration, as expected.