“…It is known that the Ni n complexes can form two types of coordination geometry with the L ligands: octahedral high-spin neutral or cationic complexes, such as [NiL2(NO2)2] (Bourosh, Revenko, Simonov, Gerbeleu, Dvorkin & Malinowski, 1987) and [NiL2im2]I2 (Revenko, Bourosh, Gerbeleu, Simonov, Virtosu & Malinowskii, 1989) and square-planar low-spin cationic complexes, such as [NiL2]Z2 (Leovac, Babin, Canic & Gerbeleu, 1980) where R1. = R2 = R3 = R4 = H; X = C1, Br, I.…”