Search results for "Cobalt"

Duroquinone-Cyclopentadienyl-Cobalt

1963

Effects of capping agent on cobalt nanoparticles

2009

The achievement of high information density and fast recording rate in memory devices crucially depends on the structure of magnetic domains. In this paper cobalt nanoparticles are synthesised using two capping agents (TOA, ODA) and two different preparation routes: thermal decomposition (TD) and Solvated Metal Atom Dispersion (SMAD). The interaction of capping agents with free metal clusters and their influence on Co nanoparticles size, atomic structure and oxidation state is investigated by means of X-ray diffraction and X-ray absorption spectroscopy.

Spin State and Ligand Dissociation in [CpCoL2] Complexes (L = PH3, H2C=CH2): A Computational Study

1999

International audience; The relative energies of [CpCoL] compounds (L = PH3, H2C=CH2) were calculated at the DFT/B3LYP level of theory. The triplet spin state was found to be favored over the singlet by between 33.0 and 21.0 kcal mol−1 for both fixed and optimized geometries. The basis set size was found to be important for the energy calculations, particularly when the energetics of ligand dissociation was examined. The role of the triplet spin state in facilitating the ligand dissociation process is discussed.

Fabrication of cobalt and cobalt oxide/graphene composites: towards high-performance anode materials for lithium ion batteries.

2010

Antibacterial studies, DNA oxidative cleavage, and crystal structures of Cu(II) and Co(II) complexes with two quinolone family members, ciprofloxacin…

2005

Nine coordination compounds of Cu(II) and Co(II) with Ciprofloxacin (HCp) and Enoxacin (HEx) as ligands have been prepared and characterized. Single crystal structural determinations of [Cu(HCp)2(ClO4)2].6H2O (1) and [Co(HEx)2(Ex)]Cl.2CH(3)OH.12H2O (4) are reported. The crystal of 1 is composed of [Cu(HCp)2(ClO4)2] units with the two perchlorate anions semicoordinated, and uncoordinated water molecules. The copper ion, at a crystallographic inversion centre, is in a tetragonally distorted octahedral environment. The structure of 4 consists of cationic monomeric [Co(HEx)2(Ex)]+ units, chloride anions, and uncoordinated methanol and water molecules. The complex is six-coordinate, with a sligh…

BIOALGA reactor: preliminary studies for heavy metals removal

2002

Abstract Microalgae have a high affinity for polyvalent metals, for that reason they could be used to reduce the concentration of heavy metals present in water and wastewater. In the present work an evaluation of a rotary biofilm reactor for algae immobilization (BIOALGA) with the subject of heavy metal removal was investigated. The BIOALGA reactor consisted of a pilot scale model that was operated with synthetic wastewater with an initial concentration of 3000 μg/l of cobalt ion. Scenedesmus obliquus was immobilized in the reactor, which was operated in batch mode for a period of 20 days. The rotary velocity used, 2 rpm, was constant during the experiment. A maximum removal of cobalt ion o…

Deep oxidation of pollutants using gold deposited on a high surface area cobalt oxide prepared by a nanocasting route.

2011

Gold deposited on a cobalt oxide with high surface area (138 m2 g−1), obtained through a nanocasting route using a siliceous KIT-6 mesoporous material as a hard template, has demonstrated high activity for the total oxidation of propane and toluene, and ambient temperature CO oxidation. The addition of gold promotes the activity when compared to a gold-free Co3O4 catalyst prepared using the same nanocasting technique. The enhanced catalytic activity when gold is present has been explained for the deep oxidation of propane and toluene in terms of the improved reducibility of cobalt oxide when gold is added, rather than to the intrinsic activity of metallic gold particles. The improved behavi…

Trace metals supplementation in anaerobic membrane bioreactors treating highly saline phenolic wastewater

2017

Biomass requires trace metals (TM) for maintaining its growth and activity. This study aimed to determine the effect of TM supplementation and partitioning on the specific methanogenic activity (SMA), with a focus on cobalt and tungsten, during the start-up of two lab-scale Anaerobic Membrane Bioreactors (AnMBRs) treating saline phenolic wastewater. The TM partitioning revealed a strong accumulation of sodium in the biomass matrix and a wash-out of the majority of TM in the reactors, which led to an SMA decrease and a low COD removal of about 30%. The SMA exhibits a maximum at about 6 g Na+ L−1 and nearly complete inhibition at 34 g Na+ L−1. The dose of 0.5 mg L−1 of tungsten increases the …

Graphene coating obtained in a cold-wall CVD process on the Co-Cr Alloy (L-605) for medical applications

2021

Graphene coating on the cobalt-chromium alloy was optimized and successfully carried out by a cold-wall chemical vapor deposition (CW-CVD) method. A uniform layer of graphene for a large area of the Co-Cr alloy (discs of 10 mm diameter) was confirmed by Raman mapping coated area and analyzing specific G and 2D bands

Constrained formation of 2-(1-(arylimino)ethyl)-7-arylimino-6,6-dimethylcyclopentapyridines and their cobalt(ii) chloride complexes: synthesis, chara…

2015

A series of 2-(1-(arylimino)ethyl)-7-arylimino-6,6-dimethylcyclopentapyridine derivatives (L1-L5) was synthesized, and individually reacted with cobalt(II) chloride to form the corresponding cobalt chloride complexes (C1-C4). These compounds were characterized, and the single crystal X-ray diffraction for two representative cobalt complexes was carried out. The molecular structures indicate that 2,7-bis(arylimino)cyclopentapyridines act as tridentate ligands; however, one of the Co-N coordinative bonds is weak due to the spatial separation of nitrogen atoms. Upon activation with either MAO or MMAO, all cobalt complexes exhibit catalytic activities toward ethylene. Polymerization takes place…