Cobalt complexes, with triamines

The E values for macrobicyclic cobalt complexes in aqueous solutions differ by 1400 V (from -550 to 840 mV). For nonmacrocyclic cobalt complexes with diamines and triamines, the E values change from -630 to 280 mV. The potentials for [Co(NH3)6] and [Co(en)3] ions occupy an intermediate position in this range [4, 344]. 

The mechanism of the reaction of (ethylenediamine)(diethylene-triamine)cobalt(II) complexes with O2 to give the mononuclear Co(III) compound has been investigated by using Co It is concluded that the peroxo... 

When dap reacts with an aromatic 3,3-triamine in the presence of nickel(II), copper(II) or cobalt(II) perchlorate in ethanol, macrocyclic complexes with tetra-dentate ligands [M(L712)](C104)2 and having octahedral structures are isolated (Eq. 3.35) [73]. 

A bis-triamine [Co(tame)]3+ complex also reacted with formaldehyde and aldehydes of carboxylic acids RCHO (where R is CHs, C2H5, or (CH3)2CH)) to form cobalt (III) triiminosarcophaginates... 

Azide ion, both free and bound to metal-ion complexes, also absorbs strongly in this range. A comparison between the infrared spectra of azide bound to diethylene-triamine Zn(II) and Co(II) complexes or to the cobalt-enzyme and the corresponding spectrum for the native enzyme showed that the azide ion is coordinate to the Zn(II) atom of the native enzyme. Examination of the difference spectra in the presence of both azide and CO2 showed that the bound azide sterically interferes with the binding of CO2 in the hydrophobic cavity adjacent to the Zn(ll). 

In the case of aliphatic triamines, (1-1-1) template condensation can be achieved if the number of atoms separating terminal NH2 groups equals 7. Thus, by interaction of dipropylenetriamine with dap on manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) matrices, it is possible to synthesise the 14-membered macrocyclic ligand L695 as appropriate complexes (Eq. 3.30) [71, 72, 74-76]. 

---