Chemical/chemicals nitrogen cobalt

The sorption processes for cobalt complexes can be complicated by hydrolysis reactions of the complex in solution, surface induced ligand loss processes, sorption of hydrolysis products of either amine, protonated amine, or mixed amine/aquo cobalt complexes, and oxidation/reduction processes associated with cobalt. The principal objective of the XPS studies was to evaluate, the chemical state of cobalt and amine ligands, the surface concentration of the respective elements, and the ligand to cobalt ratio as indicated by the surface nitrogen to cobalt atomic ratio. 

Crystal structures of the bismuth molybdate and of the mixed iron and cobalt solid solution molybdate samples were controlled by X-ray diffraction (10). The chemical compositions of the samples were determined by atomic absorption and their surface areas measured by nitrogen adsorption using the BET method. 

Chemically, proteins are distinguished from other body substances in that all proteins contain nitrogen. Some contain sulfur, phosphorus, iron, iodine, cobalt, and other elements, some of which are generally not thought of as components of the life process, but which nevertheless do play extremely important roles (e.g., as catalysts), even if present only in very minute quantities. 

The dependence of the principal components of the nuclear magnetic resonance (NMR) chemical shift tensor of non-hydrogen nuclei in model dipeptides is investigated. It is observed that the principal axis system of the chemical shift tensors of the carbonyl carbon and the amide nitrogen are intimately linked to the amide plane. On the other hand, there is no clear relationship between the alpha carbon chemical shift tensor and the molecular framework. However, the projection of this tensor on the C-H vector reveals interesting trends that one may use in peptide secondary structure determination. Effects of hydrogen bonding on the chemical shift tensor will also be discussed. The dependence of the chemical shift on ionic distance has also been studied in Rb halides and mixed halides. Lastly, the presence of motion can have dramatic effects on the observed NMR chemical shift tensor as illustrated by a nitrosyl meso-tetraphenyl porphinato cobalt (III) complex. 

Boyle was both an alchemist and chemist, but the researchers who followed him left alchemy behind as they pursued the new science of chemistry. Their experiments, which were now carefully written down and repeated, revealed new metals, like cobalt and nickel, and new gases, such as nitrogen and oxygen. In 1789, the French chemist Antoine Laurent de Lavoisier (1743-1794) offered the first modern definition of an element a chemical substance... 

Unlike cobalt and rhodium, the chemistry of polynuclear iridium carbonyl derivatives has not been studied in detail (15a). Reduction of Ir4(CO)i2 under carbon monoxide with K2C03 in methanol gives the yellow tetranuclear hydride derivative [Ir4(CO)nH], whereas under nitrogen the brown dianion [Ir8(CO)2o]2- has been isolated as a tetraalkylam-monium salt (97). It has been suggested that the structure of the dianion could result from the linking of two iridium tetrahedra, although its formulation so far is based only on elemental analyses. Clearly such an interesting compound deserves further chemical and structural characterization. 

Chemical vapor deposition method is used as an alternative to circumvent the limitations of the other synthetic methods. In chemical vapor deposition method, a substrate is prepared with a layer of metal catalyst particles, most commonly nickel, cobalt, iron, or a combination of these materials. The diameter of the grown nanotubes is related to the size of the metal particles. The substrate is heated to approximately 700°C. To initiate the growth of nanotubes, two gases are bled into the reactor a process gas (such as ammonia, nitrogen, hydrogen, etc.) and... 

The cobalt complexes are all diamagnetic and behave as 1 1 electrolytes in methanol.7 The infrared spectra of the complexes contain sharp, strong N—H stretching absorptions (Table I). The electronic spectral data are also shown in Table I. Isomers I and II differ in the chiralities of nitrogen atoms in the macro-cyclic ligands.7 Both chemical and physical properties are dependent on ring... 

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