Cations cobalt

Naphthaleneacetic acid has also been prepared by the carbonyl-insertion reaction of 1-chloromethylnaphthalene cataly2ed by carbonyl cobalt cation (90,91). Carboxylation of 1-chloromethylnaphthalene in the presence of the catalyst Pd[P(CgH )2]2Cl2 under phase-transfer conditions gave 1-naphthaleneacetic acid in 78% yield (92). 

The detection limits for iron and cobalt cations on cellulose layers are 2 and 20 ng substance per chromatogram zone [1]. 

Nickel cations (hRf 35-40) appeared as red and cobalt cations (h/ij 40-45) as yellow chromatogram zones on a colorless background. 

Based on previous studies [15, 22-25], the band at 1941 cm-i is assigned to Co2+(NO), and the pair of bands at 1894 and 1815 cm-i, to Co2+(NO)2- The shoulders at 1874 and 1799 cm may be due to a second dinitrosyl species. While little is known about the location and coordination of the Co 2+ in ZSM-5, it is likely that cobalt ions are associated with both [Si-0-Al]- and [Al-0-Si-0-AI]2- structures in the zeolite. In the former case, the cobalt cations are assumed to be present as Co2+(OH-) cations and in the latter case as Co2+ cations. The presence of cobalt cations in different environments could account for the appearance of two sets of dinitrosyl bands. The band at 2132 cm-> is present not only on Co-ZSM-5 but also on H-ZSM-5 and Na-ZSM-5, and has been observed by several authors on Cu-ZSM-5 [26-28]. 

Studies conducted to examine the mode of activation of MAO with bis(imino) pyridine cobalt halide systems have shown some intriguing findings. With regard to 6a/MAO, initial reduction of the cobalt(II) precatalyst to cobalt halide followed by conversion to a cobalt methyl and ultimately to a cobalt cationic species has been demonstrated (see Sect. 2.6) [108, 109], Addition of ethylene affords an eth-... 

EXAFS data at the Co and Al K edges for Co Al - Cl LDHs were consistent with an ordered array of cations for n = 2,3 and 4. In each case the Al has a second coordination shell of 6 Co ions and the Co has a second shell of 6/n Al and (6-6/ ) Co next nearest neighbors [46]. The peaks arising from the focusing effect are still observed in the Co K edge EXAFS of the material showing that the cobalt cations in the layers remain ahgned. 

Alike metallocomplex anion-radicals, cation-radicals of odd-electron structure exhibit enforced reactivity. Thus, the 17-electron cyclopentadienyl dicarbonyl cobalt cation-radical [CoCp(CO)2] undergoes an unusual organometallic chemical reaction with the neutral parent complex. The reaction leads to [Co2Cp2(CO)4]. This dimeric cation-radical contains a metal-metal bond unsupported by bridging ligands. The Co—Co bond happens to be robust and persists in all further transformations of the binuclear cation-radical (Nafady et al. 2006). 

Murray et al. (2) prepared permeable membranes for selectively removing phosphate, nitrate, and ferric cations by polymerizing and crosslinking with the modified matrix monomer, (bis-acrylamindo-phenanthroline)dinitrate, (IV), to produce an ion permeability substrate. Kulkami et al. (3) selectively removed cobalt cations from solution using 2-hydroxy ethyl methacrylate copolymers,... 

Benzothiazolylformazans form complexes of composition L2M2+ with nickel, copper and cobalt cations (184). 

When the solution secured according to Equation (2) is treated with about 200 atmospheres of pure carbon monoxide at 180-200°, some gas is slowly absorbed. When the reaction is repeated with a mixture of hydrogen and carbon monoxide, gas absorption occurs below 100° and is rapid and non-reversible. Both hydrogen and carbon monoxide are absorbed. It is possible that under these conditions, the electrons required for the reduction of the cobalt cation are furnished by hydrogen ... 

This simple hydration theory cannot explain all the known phenomena, as, for example, the opposite effects of calcium chloride and zinc chloride on the colours. Engel2 therefore assumed that the observed colours were due to certain double salts present in the solutions. In the case of pure cobalt chloride, hydrolysis was supposed to occur on heating the solution, the hydrochloric acid liberated uniting with unchanged cobalt chloride and as an explanation of the colour change this is almost certainly incorrect. Ostwald 3 suggested a simple ionic explanation, namely, that the red colour is that of the cobalt cation, and the blue that of the undissociated salt. This is certainly not a complete explanation, and seems to necessitate a very marked decrease in ionisation with rise of temperature, which experiment, so far, does not support.4... 

It was shown in [18] that practically monophase fine barium hexaaluminate can be obtained by mechanical activation of a mixture of barium oxide with Y-AI2O3, which exhibits acid properties to a larger extent than a-Al203, and by consequent thermal treatments at increased temperature. The product then is grinded in the presence of water. The synthesis was shown to proceed almost completely after activation for 5 min in the AGO-2 planetary mill and thermal treatment at 1300°C for 1 h. Mechanical activation of the mixture of aluminium hydroxide with barium oxide, followed by thermal treatment at 900°C, results in the formation of the final product and a-Al203 as an admixture which remains even at 1300°C. Mechanochemical synthesis helped also to synthesize barinm hexaaluminate in which a part of aluminium cations is replaced with manganese, iron, cobalt cations. Such compounds are nsed as active ceramics in catalysis [17]. 

Scheme 33. The first intermediate in this reaction, the exo-haloborylcyclopentadiene(cyclopentadienyl)cobalt (44) cannot be isolated because the solvolytic riag expansion to the (l-boratacyclohexadienyl)(cyclopentadienyl)cobalt cation (45+) occurs spontaneously, even in nonpolar solvents. The boracyclic cation (45+) is reduced by excess cobaltocene, and the neutral complex (45) can undergo the same reaction cycle, leading finally to the bisborabenzene complex (46).

An attempt to prepare the corresponding complex of 6,6-dimethyl-fulvene via the Grignard reaction resulted in hydrogen addition to yield the bis(77-isopropylcyclopentadienyl)cobalt cation (216). 

Catalyst Composition. Chemical compositions of typical nickel and cobalt zeolites are summarized in Table 1. Based on the total CEC derived from the initial sodium composition, 23 to 37% of the Zeolon and 8.4% of the Linde SK400 exchange sites are occupied by nickel cations. In Zeolon, 55% of the exchange sites are occupied by cobalt cations. A ratio of 1.41 1 for cobalt to nickel on the Zeolon exchange sites resulted where nickel and cobalt were exchanged under comparable conditions. 

A solid-state promotion of CuH-ZSM-5 zeolite by cobalt ions results in the over-additive increase of the catalyst activity in C2Hg total oxidation, and leads to the rise of the thermostability of the bi-cationic catalyst. The insertion of cobalt cations into zeolitic channels with stabilization of Cu " active sites is assumed. 

Dihydrogen adsorbed by a partially cobalt-exchanged NaZA at 50 K to a concentration of 0.5 H2 per supercage was considered to be bound end-on to the cobalt cations, pointing along a body diagonal in the direction of the electrostatic field lines of the cavity [33], a 1-D type model, as in Table 6.4. The bound hydrogen molecule performed 180° re-orientations with a barrier of 5.3 to 6.6 kJ mof. The peak at 31 cm" (Table 6.6) is then the transition to (J= 1, M= 0). 

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