Although, complexes 1 and 2  display differences in the nature of the bonds, the overall bonding properties of Bk(IV) are quite the same (Table S8, ESI). This means that the ‘availability’ of Bk(IV) to form Bk–O bonds is essentially the same, but the way it forms those bonds is tunable. It would be interesting to see if this holds for Bk(IV) bonds other than oxygen-donor ligands.