A Square‐Planar Nickel(II) Monoradical Complex with a Bis(salicylidene)diamine Ligand

Abstract

Abstract The new square‐planar Ni II –N 2 O 2 complex [Ni( Me L)] ( 1 Me ), where Me L stands for the dianionic phenolato form of N , N′ ‐bis(3,5‐di‐ tert ‐butyl‐salicylidene)‐4,5‐dimethyl‐1,2‐phenylenediamine ( Me LH 2 ), has been synthesised and fully characterised. X‐ray crystallography was also used for the characterisation. The electrochemical one‐electron oxidation of 1 Me produces the thermally stable (within the temperature range 10–295 K) cationic species ( 1 Me ) + . The UV/Vis and X‐band EPR experimental data, supported by DFT calculations, indicate that ( 1 Me ) + is best described as a Ni II monoradical complex and, thus, does NOT exist in a Ni III ground state, in contrast to its demethylated counterpart [Ni( H L)] + ( 1 H ) + below 170 K.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)