Nickel precursors based on diamagnetic and paramagnetic di(imine)pyridine ligands for magnetic materials: Synthesis, X-ray structures and magnetic studies

Abstract Structural characterization and spectroscopic studies of the (2-acetyl-6-(1-TEMPO-imino)ethyl)pyridine (pat) and the 2,6-bis(1-TEMPO-imino)ethyl)pyridine (pbtMe) ligands are presented. Their electrochemical properties are also discussed. Two new nickel complexes, [Ni II (dip)(CH 3 CN)(H 2 O) 2 ](BF 4 ) 2 ( 1 ) (dip = 2,6-(di-iminepyridine)) and [Ni II (pbtMe)(CH 3 CN) 3 ](BF 4 ) 2 ( 2 ) have been characterized by X-ray diffraction. The reaction of 1 with the tetraethyl ammonium pentacyanopropenide salt (Et 4 N)(pcp) affords the new compound [Ni II (pcp)(dip)(CH 3 CN)](pcp) ( 3 ) for which X-ray diffraction studies evidence an usual bridging μ 2 coordination mode for the pentacyanopropenide anion, leading to chains running along the [1 0 0] direction with Ni⋯Ni intra-chains distances of 10.653 A. Magnetic measurements for 3 indicate that it presents antiferromagnetic interactions that can be reproduced with a S = 1 regular chain model with g = 2.115(1) and J chain  = −0.589(5) cm −1 .