Lithium insertion studies on boron-doped diamond as a possible anode material for lithium batteries

Boron-doped diamond (BDD) was prepared by the hot filament chemical vapor deposition method. The prepared samples were subjected to X-ray diffraction, scanning electron microscopy, and Raman spectroscopy studies. The BDD composite electrode/Li cell has been assembled, and its cycling behavior was studied. The BDD possesses large sp² sites, which effectively participate in the lithium storage process. Furthermore, nanocrystalline tin (Sn) particles were prepared by the chemical reduction method. The addition of nanotin with the BDD-active material greatly enhances the cyclability of the cell. An erratum to this article can be found at     

Synthesis and biological activities of novel ethers of quinolinone linked with coumarins

Abstract  

A series of new ethers of quinolinone linked with different substituted coumarins and benzofurans were synthesized from 4-(bromomethyl)quinolinones. All newly synthesized compounds were screened for their in vitro antibacterial and antifungal activities. Most of the compounds with chloro substitution at the C-6 or C-7 position in quinolinone showed potent antibacterial and antifungal activities. In pharmacological evaluations, some of these chloroquinolinones also showed 70–77% inhibition of inflammation after 8 h, whereas the other compounds showed 51–55% inhibition. Most of the compounds showed potent analgesic activity compared to the standard and control. The structures of all newly synthesized compounds were characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, and EI-MS.     

Cucurbit[7]uril as a Tool in the Green Synthesis of Gold Nanoparticles

A simple, green, one‐pot synthesis of gold nanoparticles was achieved through the reaction of an aqueous mixture of potassium tetrachloroaurate(III) and the macrocycle cucurbit[7]uril in the presence of sodium hydroxide at room temperature without introducing any kind of traditional reducing agents and/or external energy. The as‐prepared gold nanoparticles showed catalytic activity for the reduction reaction of 4‐nitrophenol in the presence of NaBH₄, which has been established by visual inspection and UV/Vis spectroscopy. This report is the first for the preparation of gold nanoparticles using cucurbit[7]uril in aqueous media through chemical reduction without employing conventional reducing agents and/or external energy.     

A green approach to fabricate CuO nanoparticles

Uniform copper oxide (tenorite) nanoparticles have been prepared via a green pathway by thermal decomposition, using a novel supramolecular complex, in which β-cyclodextrin is selected to encapsulate the precursor copper(II) acetate.     

Synthesis and biological studies of some new acrylic acid ethyl esters of quinolinone

Abstract  

A series of new acrylic acid ethyl esters of quinolinones were synthesized from 4-(bromomethyl)quinolinones and screened for in vitro antimicrobial and in vivo analgesic and anti-inflammatory activities. Most of the compounds with chloro substitution at the C-6 or C-7 position in the quinolinone moiety and a methoxy group in the aryloxy moiety showed potent antibacterial and antifungal activities when compared with non-halogenated quinolinones and the quinolinones bearing a CH₃ at the C-8 position. In a pharmacological evaluation, the halogen substitution at the C-6 or C-7 position in quinolinones was found to enhance both analgesic and anti-inflammatory activities of the molecule when compared with a simple unsubstituted (non-halogenated) quinolinone. The structures of all newly synthesized compounds were characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, and FAB-MS.     

Reversal of Regioselectivity in Asymmetric C−H Bond Annulation with Bromoalkynes under Cobalt Catalysis**

Metal-catalyzed asymmetric C−H bond annulation strategy offers a versatile platform, allowing the construction of complex P-chiral molecules through atom- and step-economical fashion. However, regioselective insertion of π-coupling partner between M−C bond with high enantio-induction remain elusive. Using commercially available Co(II) salt and chiral-Salox ligands, we demonstrate an unusual protocol for the regio-reversal, enantioselective C−H bond annulation of phosphinamide with bromoalkyne through desymmetrization. The reaction proceeds through ligand-assisted enantiodetermining cyclocobaltation followed by regioselective insertion of bromoalkyne between Co−C, subsequent reductive elimination, and halogen exchange with carboxylate resulted in P-stereogenic compounds in excellent ee (up to >99 %). The isolation of cobaltacycle involved in the catalytic cycle and the outcome of control experiments provide support for a plausible mechanism.     

A Facile Approach to Single‐Wall Carbon Nanotube/Poly(allylamine) Nanocomposites

A facile approach to polymer nanocomposites with single‐wall carbon nanotubes and cationic polymers is reported. The composite material was synthesized by producing carboxylic acid groups at the nanotube termini followed by a reaction with poly(allylamine) in water. Fourier transform infrared spectral and thermogravimetric analyses corroborate that the poly(allylamine) chains were wrapped on the surface of the carbon nanotubes. The scanning electron microscopic (SEM) image shows that the nanotubes were dispersed with little aggregation, thus, strongly suggesting that the poly(allylamine) chains have covered the single‐wall carbon nanotubes, which was further evidenced by transmission electron microscopy. The composites are soluble in water, and this solubilization process opens up new opportunities in the solution chemistry on pristine nanotubes.

     

Transition metal complexes of pyrazinecarboxylic acids with neutral hydrazine as a ligand

New divalent Co, Ni, Zn and Cd pyrazinecarboxylate hydrazinates of the formulae M(pyzCOO)₂·nN₂H₄·xH₂O and Mpyz(COO)₂·N₂H₄·xH₂O obtained by the reaction of respective metal nitrate hydrates with 2-pyrazinecarboxylic (HpyzCOO)/2,3-pyrazinedicarboxylic (H₂pyz(COO)₂) acid and hydrazine hydrate have been characterized on the basis of analytical, spectroscopic (electronic and infrared), thermal and X-ray powder diffraction studies. The electronic spectroscopic data suggest that the cobalt and nickel complexes are of spin-free (high-spin) type with octahedral geometry. The IR absorption bands of N-N stretching in the range 980-972 cm^-1 unambiguously prove the bidentate bridging nature of the N₂H₄ ligand. The hydrazinate complexes of 2,3-pyrazinedicarboxylate lose hydrazine molecule exothermally, whereas 2-pyrazinecarboxylate compounds lose the same endothermally. Further, all the complexes undergo endothermic (dehydration and/or dehydrazination) followed by exothermic decomposition except the Zn and Cd complexes of 2,3-pyrazinedicarboxylate, which show only exothermic decomposition. In order to know the isomorphic nature among the complexes, the X-ray powder patterns have been compared.