X-ray diffraction, spectral and magnetic studies of the nickel(II) thiocyanate complexes with tridentate 2,6-dithiocarboxamidopyridine SNS and 2,6-dicarboxamidopyridine ONO ligands: Influence of donor atoms on the coordination geometry of nickel

The unusual structural feature in the complex [Ni2(μ-NCS)2(NCS)2(S-dept)2] [S-dept = N,N,N′,N′-tetraethylpyridine-2,6-dithiocarboxamide] (1) is the presence of N-bonding bridging NCS groups between the Ni(II) atoms with the highest asymmetry. The magnetic-exchange interactions between the metal ions are small but significant. The coordination around Ni in the complexes [Ni(O-deap)(NCS)2 · CH3CN] · CH3CN (2) and [Ni(O-deap)(NCS)2 · C2H5OH] (3) [O-deap = N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamide] is distorted octahedral with a substantial difference in approach of the two thiocyanate ligands towards the coordination polyhedra. Complexes 2 and 3 show significant differences in their molecular packing.