From these calculations we can conclude that that a change in oxidation state levels from [Mn III 6Mn in compound 4 to [Mn III 4Mn in compound 3 results in a significant decrease in the magnitude of some antiferromagnetic exchange contributions (J1 = -4.8 cm -1 (3), -40.4 cm -1 (4)), a switch from ferromagnetic to antiferromagnetic in others (J2 = -1.1 cm -1 (3), +3.1 cm -1 (4); J5 = -0.2 cm -1 (3), +4.1 cm -1 (4)), and the loss of significant spin frustration. The computed spin density plots for the high spin state of complexes 3 and 4 are given in Fig. , with the spin density plots for all the broken symmetries computed given in Figure .