Metamagnetic behavior of [Ni(4ImNNH)2(NO3)2] having a ground high-spin state (4ImNNH=4-imidazolyl nitronyl nitroxide)

A new chelating radical ligand 4ImNNH (2-(4-imidazolyl)-4,4,5,5-tetramethylimidazolin-1-yloxyl 3-oxide) was prepared, and complexation with nickel(II) nitrate gave [Ni(4ImNNH)2(NO3)2] as a discrete mononuclear complex. Magnetic measurements revealed that [Ni(4ImNNH)2(NO3)2] had a ground high-spin state (Stotal=2) and exhibited metamagnetic behavior below 3.4 K.