Conformational isomers of neutral trans-dinitrocobalt(III) complexes.

The reaction of Co(acac)3 with N-(2-aminoethyl)-1,3-propanediamine in the presence of NaNO2 results in the preparation of an unexpected dinitrocobalt(III) compound, (11-amino-4-methyl-5,8-diazaundeca-2,4-dien-2-olato-kappa4N(5,8,11),O)-dinitrocobalt(III), [Co(C10H20N3O)(NO2)2], containing the tetradentate anion of 11-amino-4-methyl-5,8-diazaundeca-2,4-dien-2-ol. Two isomers of the compound were obtained by recrystallization of the crude product. In one isomer, the two trans nitro groups are staggered, and in the other they are eclipsed.