Flexible carbon nanostructures with electrospun nickel oxide as a lithium-ion battery anode

Carbon nanostructures (CNS) with high electrical conductivity and unique branched structure of carbon nanotubes combined with NiO nanofibers (NFs) were used as anode for lithium-ion batteries. CNS works as a framework substrate for the anodic conversion reaction of nickel oxide (NiO). Electrochemical performance and behavior of CNS/NiO anodes is compared with the conventional carbon (C)/NiO anodes. CNS/NiO NF-based anode retains high specific capacity under different current densities compared to C/NiO anode. Moreover, specific capacity as high as 450 mAh/g for CNS/NiO NF anode is observed compared to only 90 mAh/g for C/NiO NFs using a current density of 500 mA/g after 500 cycles. This improved performance is attributed to the highly conductive network of CNS leading to efficient charge transfer. The high porosity, electrical conductivity as well as the branched and networked nature of CNS reveal to be of critical importance to allow the electrochemical conversion reactions.     

PtII Coordination to N1 of 9‐Methylguanine: Why it Facilitates Binding of Additional Metal Ions to the Purine Ring

The preparation and X‐ray crystal structure analysis of {trans‐[Pt(MeNH₂)₂(9‐MeG‐N1)₂]} ? {3 K₂[Pt(CN)₄]} ? 6 H₂O ( 3 a ) (with 9‐MeG being the anion of 9‐methylguanine, 9‐MeGH) are reported. The title compound was obtained by treating [Pt(dien)(9‐MeGH‐N7)]²⁺ ( 1 ; dien=diethylenetriamine) with trans‐[Pt(MeNH₂)₂(H₂O)₂]²⁺ at pH 9.6, 60 °C, and subsequent removal of the [(dien)Pt^II] entities by treatment with an excess amount of KCN, which converts the latter to [Pt(CN)₄]^2?. Cocrystallization of K₂[Pt(CN)₄] with trans‐[Pt(MeNH₂)₂(9‐MeG‐N1)₂] is a consequence of the increase in basicity of the guanine ligand following its deprotonation and Pt coordination at N1. This increase in basicity is reflected in the pK_a values of trans‐[Pt(MeNH₂)₂(9‐MeGH‐N1)₂]²⁺ (4.4±0.1 and 3.3±0.4). The crystal structure of 3 a reveals rare (N7,O6 chelate) and unconventional (N2,C2,N3) binding patterns of K⁺ to the guaninato ligands. DFT calculations confirm that K⁺ binding to the sugar edge of guanine for a N1‐platinated guanine anion is a realistic option, thus ruling against a simple packing effect in the solid‐state structure of 3 a . The linkage isomer of 3 a , trans‐[Pt(MeNH₂)₂(9‐MeG‐N7)₂] ( 6 a ) has likewise been isolated, and its acid–base properties determined. Compound 6 a is more basic than 3 a by more than 4 log units. Binding of metal entities to the N7 positions of 9‐MeG in 3 a has been studied in detail for [(NH₃)₃Pt^II], trans‐[(NH₃)₂Pt^II], and [(en)Pd^II] (en=ethylenediamine) by using ¹H NMR spectroscopy. Without exception, binding of the second metal takes place at N7, but formation of a molecular guanine square with trans‐[(Me₂NH₂)Pt^II] cross‐linking N1 positions and trans‐[(NH₃)₂Pt^II] cross‐linking N7 positions could not be confirmed unambiguously, despite the fact that calculations are fully consistent with its existence.     

Dye and its removal from aqueous solution by adsorption: A review

In this review article the authors presented up to-date development on the application of adsorption in the removal of dyes from aqueous solution. This review article provides extensive literature information about dyes, its classification and toxicity, various treatment methods, and dye adsorption characteristics by various adsorbents. One of the objectives of this review article is to organise the scattered available information on various aspects on a wide range of potentially effective adsorbents in the removal of dyes. Therefore, an extensive list of various adsorbents such as natural materials, waste materials from industry, agricultural by-products, and biomass based activated carbon in the removal of various dyes has been compiled here. Dye bearing waste treatment by adsorption using low cost alternative adsorbent is a demanding area as it has double benefits i.e. water treatment and waste management. Further, activated carbon from biomass has the advantage of offering an effected low cost replacement for non-renewable coal based granular activated carbon provided that they have similar or better adsorption on efficiency. The effectiveness of various adsorbents under different physico-chemical process parameters and their comparative adsorption capacity towards dye adsorption has also been presented. This review paper also includes the affective adsorption factors of dye such as solution pH, initial dye concentration, adsorbent dosage, and temperature. The applicability of various adsorption kinetic models and isotherm models for dye removal by wide range of adsorbents is also reported here. Conclusions have been drawn from the literature reviewed and few suggestions for future research are proposed.     

Exploration of a Cheaper Carbon Source for Extracellular β-glucosidase Synthesis from <Emphasis Type="Italic">Debaryomyces pseudopolymorphus</Emphasis> NRRL YB-4229

In the present work, interactions between common media components and fermentation conditions were explored to come up with a simple media recipe for extracellular β-glucosidase (Dβ-gl) synthesis from Debaryomyces pseudopolymorphus to substitute cellobiose, which is currently used as a sole carbon source. Taguchi L₂₅ orthogonal array design was used to screen factors influencing Dβ-gl synthesis (carbon, organic nitrogen, inorganic nitrogen, trace elements, inoculum volume, and fermentation time). A significant influence of xylose, peptone, and potassium nitrate as carbon, organic nitrogen, and inorganic nitrogen sources, respectively, on Dβ-gl synthesis was identified by Taguchi. These factors were further optimized using central composite rotatable design (CCRD) of response surface methodology (RSM). The results showed that in the range studied, potassium nitrate had insignificant effect while xylose, peptone, and xylose-peptone interaction had a significant effect on Dβ-gl synthesis. Peptone/xylose ratio of 1.33 was found to be an important parameter for inducing Dβ-gl synthesis. The regression coefficient (R ²) of 0.915 and P value of <0.0003 for the model indicated that it was highly significant. The maximum activity obtained after RSM (32.2 U/ml) was comparable with that obtained (68.8 U/ml) when cellobiose (20 g/l) was used as a sole carbon source. Considering the cost difference between xylose and cellobiose, a 16-fold cost reduction could be obtained for equivalent Dβ-gl yield. Fed-batch fermentations were carried out wherein peptone/xylose ratio of 1.33 was maintained and continuous Dβ-gl synthesis was observed.     

Gold,silver, and palladium nanoparticle/nano-agglomerate generation,collection, and characterization

Generation, collection, and characterization of gold, silver, and palladium nanoparticles and nano-agglomerates (collectively “nanoparticles”) have been explored. The nanoparticles were generated with a spark aerosol generator (Palas GFG-1000). They were collected using a deposition cell under diffusion and thermophoresis. The shapes and sizes of the deposited particles were measured using transmission electron microscopy (TEM). TEM images showed that the particles were in the range of 8–100 nm in diameter, and their shapes varied from nearly spherical to highly non-spherical. Thermophoresis enhanced the deposition of nanoparticles (over the diffusive or the isothermal deposition) in all cases. Further, the size distributions of the nanoparticles generated in the gas phase (aerosol) were measured using a scanning mobility particle sizer (SMPS 3080, TSI) spectrometer. The SMPS results show that an increase in the spark frequency of the generator shifted the size distributions of the nanoparticles to larger diameters, and the total particle mass production rate increased linearly with increase in the spark frequency. The computational fluid dynamics code Fluent (Ansys) was used to model the flow in the deposition cell, and the computed results conform to the observations.     

Tiara[5]arenes: Synthesis,Solid‐State Conformational Studies,Host–Guest Properties,and Application as Nonporous Adaptive Crystals

Tiara[5]arenes (T[5]s), a new class of five‐fold symmetric oligophenolic macrocycles that are not accessible from the addition of formaldehyde to phenol, were synthesized for the first time. These pillar[5]arene‐derived structures display both unique conformational freedom, differing from that of pillararenes, with a rich blend of solid‐state conformations and excellent host–guest interactions in solution. Finally we show how this novel macrocyclic scaffold can be functionalized in a variety of ways and used as functional crystalline materials to distinguish uniquely between benzene and cyclohexane.     

Combined experimental and computational study of W(II), Ru(II), Pt(IV) and Cu(I) amine and amido complexes using 15N NMR spectroscopy

Using 2D proton-coupled gHSQC pulse sequences in addition to 1D ¹⁵N NMR experiments of ¹⁵N labeled systems, ¹⁵N NMR chemical shifts of a range of transition metal amido and amine complexes were determined. Tungsten(II), ruthenium(II), platinum(IV) and copper(I) complexes with aniline and their anilido variants were studied and compared to free aniline, lithium anilido and anilinium tetrafluoroborate. Upon coordination of aniline to transition metals, upfield chemical shifts of 20–60 ppm were observed. Deprotonation of the amine complexes to form amido complexes resulted in downfield chemical shifts of 40–60 ppm for all of the complexes except for the tungsten d⁴ system. For the tungsten(II) complexes, the cationic aniline complex displayed a downfield shift of approximately 56 ppm relative to the neutral anilido complex. The change in chemical shift for amine to amido conversion is proposed to depend on the ability of the amido ligand to π-bond with the metal center, which influences the magnitude of the paramagnetic screening term.