Cobalt complexes ethylene tris complex

Iron(II) complex of tris(N -tert-butylurea-ylato)-N-ethylene]aminato activates dioxygen at room temperature to afford an iron(III) complex containing a single terminal oxo ligand. X-ray structures show that the three urea molecules act as a tridentate N,N,N-hgand [52]. The tripodal ligand was also used to synthesise complexes of cobalt, iron or zinc with terminal hydroxo ligands (Scheme 8) [53]. 

The use of the anionic tris(pyrazolyl)borate ligand afforded the possibility to obtain the neutral unsatured 15-electron cobalt(n) complex 19. This compound was able to react with CO leading to a carbonyl derivative, or with ethylene (at elevated temperature, however) to give a 7 1 mixture of the alkyl and an -ethene cobalt complexes. The... 

There has been some work on interactions between LSRs and transition metal complexes, both NMR shifts and relaxation rates being studied. Presumably the mode of interaction is by means of bridges formed by the donor atoms of one complex which bond in a labile manner to the metal ion of the second complex. Interactions examined include those between [Eu(fod-d[Pg.1104]

The following procedure is based on the reaction of an aqueous solution of cobalt(II) chloride with the equivalent amount of (2-aminoethyl)carbamic acid, followed by oxidation with hydrogen peroxide and the subsequent formation of bis(ethylene-diamine)cobalt(III) ions. The bis(ethylenediamine)cobalt(lII) species are converted to the carbonato complex by reaction with lithium hydroxide and carbon dioxide. During the entire preparation a vigorous stream of carbon dioxide is bubbled through the reaction mixture. This procedure appears to be essential in order to minimize the formation of tris(ethylenediamine)cobalt(III) chloride as a by-product. However, the formation of a negligible amount of the tris salt cannot be avoided. The crude salts have a purity suitable for preparative purposes. The pure salts are obtained by recrystallization from aqueous solution. 

In the first study of this sort 29) Keller and Edwards sought to prepare tris(A -hydroxyethylethylenediamine)cobalt(III) and to examine the reactivity of the uncoordinated hydroxy group. They reported such groups to be completely inert in the material they prepared. A subsequent study 15) reported that the oxidation of a basic mixture of a cobalt(II) salt and AT-hydroxyethylethylenediamine produced primarily tris(ethylene-diamine)cobalt(III). In this latter study, a method for preparing complexes of AT-hydroxyethylethylenediamine (hereafter abbreviated as etolen) was developed based upon reactions of the type ... 

Lattermann et al. reported the first metallomesogenic dendrimer when they described results on trigonal bipyramidal metal complexes of ethylene-imine dendrimers of the first and second generation, based on derivatives of tris(2-aminoethyl)amine. Complexes of cobalt, nickel, copper, and zinc were prepared and found to exhibit relatively low temperature mesophases, which generally possessed hexagonal columnar structures. These materials therefore provided the first examples of metallomesogenic dendrimers [72,73]. 

Research into iron and cobalt compounds as oligomeriza tion and polymerization catalysts has increased enormously since the disclosure that complexes of the metals with tri-dentate 2,6-diiminopyridine ligands (19 Figure 16) function as catalysts.Fe(ll) compounds with no substituents on the N-aryl rings (Ri = R2 = H) are inactive, those with one substituent (Ri = Me, R2 = H) yield oligomers and those with substituents in the 2- and 6- positions (Ri = R2 = Me) polymerize ethylene to high molecular weight material. 

Tris-triphenyl phosphine cobalt nitrogen complex, N2C0 (PPh3)3, reacts with ethylene to form an ethylene complex. Suggest a structure for this complex. 

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