Cobalt -amines

The relative instrumental sensitivity factors for cobalt and nitrogen were determined by measuring core level (Co 2p and N Is) XPS spectra for a series of pure cobalt amine complexes of established stoichiometry. To evaluate the core level photopeak intensities, peak areas, including shake-up satellite intensity were used. The precision for the measurements of the nitrogen to cobalt atomic ratio is 10% while the accuracy is approximately 15%. Additional details of the XPS measurements are contained in the literature (24,25). 

Figure 7) provides evidence also of cobalt-amine complex species. The SIMS spectrum for pure Co(en) Cl shows important ions at m/z + + 3 + +... 

Reduction potentials of hexaaminecobalt(III) complexes span a range of more than 0.9 V, with the lowest potential (-0.63 V) exhibited by rCo(tra J-diammac)]3+/2+ and the highest potential (+0.28 V) found for [Co(tmen)3]3+/2+ (for ligand structures see Table 10.1 below), /ra/is-diammac leads to relatively short metal-ligand bonds and therefore stabilizes the cobalt(III) state, tmen leads to relatively long cobalt-amine... 

Sepulchrates (7) are the most noted of the caged macrocyclic ligands and are the nitrogen analogs of the cryptands. The Co-N distances are 1.99 A for Co and 2.16 A for Co from crystallographic data, and do not vary greatly from other cobalt amines. ... 

Since the early days of coordination chemistry, cobalt amine complexes have played a dominant role. The classical work of Werner and... 

The electronic structure, in particular the electronic spectroscopic properties, of the whole class of cobalt amine complexes may be reduced to a discussion of the central Co-Ne core. This disregards, of course, the charge-transfer transition that in these compexes typically occurs around 250 nm. The geometrical structure is either octahedral or is defined in terms of a subgroup of the cubic point group Oh, where the... 

Since the beginnings of experimental and theoretical investigations of electron-transfer reactions, the various cobalt amine complexes have... 

Clark oxygen electrode 977, 979 Claycop, use in nitration 633 Cluster formation 929 Clustering energies, gas-phase 224 CMPO derivatives 1406 Co-antioxidants 892 Cobalt-amine complexes, as oxidation catalysts 1199, 1201, 1205, 1206, 1209, 1211... 

Diamine complexes. The pK values determined for a range of cobalt(iii)-amine chelates indicated enhanced acidity for the protic chelate complexes compared with those with related unidentate ligands." Complete resolution of rac-[Co(en)3] cations has been achieved by paper electrophoresis in a background of d-tartrate and AlC. The crystal structure of (-H)D-[Co(en)3](N03)3 has been determined. The very low quantum yields for the photoreactions of [Co(en)3] have been explained as due to the lack of ligand field excitation for this ion. However, convincing evidence is presented for the reaction of [Co(en)3] " and [Fe(CN)g] under photochemical conditions indicating that this is an efficient photochemical reaction of the cobalt-amine complex in a ligand field excited state (quantum yield ca. 0.2). ... 

Bult, A., The cobaltous amine reaction 1. The behaviour of the 5,5-disubsti-tuted barbituric acids, Pharmaceutisch Weekblad, 111, 157, 1976. 

Oxygen adducts are readily formed by the air bubbling of a solution of cobalt amine complex. Similar p-peroxo cobalt(III) complexes are formed by the reaction of oxygen with a variety of cobalt(II) chelates. The amine ligands in oxygen-binding complexes also have been extended to polyamines, such as poly(ethyleneimine) (details are given in Experiment 9-4, Section 9.5). 

There are also dimethylaniline with dibenzoyl peroxide at room temperature (for normal/long gel times) dimethylparatoluidine (for very short gel times) cobalt octoate (mainly used with ketone peroxides for polyesters at room and elevated temperatures) cobalt/amine very high reactivity with ketone peroxides for very fast cure (for example polymer concrete) and vanadium special for ketone peroxide. 

Materials/characteristics Organic peroxides. Cobalt/amine/vanadium compounds. Aliphatic amines. Ketones, anhydrides, etc. 

Cobalt/amine very high reactivity with ketone peroxides for very fast cure (for example, polymer concrete) ... 

Fig. 8.4. Structures of cobalt—amine complexes with radiosensitizing properties.

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