Coordination‐induced Spin State Switching of an Aminyl‐radical‐bridged NiII‐Porphyrin Dimer between Doublet and Sextet States

A bis(NiII‐porphyrinyl)aminyl radical with meso‐C6F5 groups was prepared as a spin‐delocalized stable aminyl radical with a doublet spin state. Upon addition of pyridine, both NiII centers became hexacoordinated by accepting two axial pyridines, which triggered a spin state change of the NiII centers from diamagnetic (S = 0) to paramagnetic (S = 1). The resulting high‐spin NiII centers interact with the aminyl radical ferromagnetically to give rise to an overall sextet state (S = 5/2). Importantly, this coordination‐induced spin‐state switching can be conducted in a reversible manner, in that washing of the high‐spin radical with aqueous hydrochloric acid regenerates the original doublet radical in good yield.

from A via a.sfakia on Inoreader http://bit.ly/2GqOJX3