Acetic acid, ethylenediamine cobalt complexes

The condensation of 2V,A -bis(3-aminopropyl)ethylenediamine (7V,A -ethylene-bis[l,3-propanediamine]) as its acid salt with 2,3-butanedione (biacetyl) in the presence of cobalt(II) or nickel(II) acetate gives complexes of 2,S-Mej [14] - 1,3-diene-l,4,8,11-N4 containing one a-diimine linkage. Experiments have shown that the presence of H ion determines whether or not a macrocyclic complex forms and that, in the presence of H, the time at which the metal acetate is added to the reaction mixture influences the yield of the complex. Unlike the reaction between biacetyl and 1,3-propanediamine to form 2,3,9,10-Me4[14]-1,3,8,10-tetraene-l,4,8,11-N4 (Sec. 4), the condensation of biacetyl withTVA -bis(3-aminopropyl)ethylenediamine is particularly sensitive to excess acetate so that the procedures given use the optimized conditions. 

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