Oxidative dehydrogenation of a new tetra-amine N-4-donor macrocycle tunes the nickel(II) spin state from high spin to low spin

The nickel(II) spin state in a series of N-4-donor macrocycles differing in the number of imine bonds is tuned from low spin (2 imines) to low or high spin (1 imine; non- or coordinating co-ligand) to high spin (no imines).