Five-co-ordination with ‘hybrid’ ligands. Part V. Cobalt(II) and nickel(II) complexes with tetradentate ligands containing nitrogen and phosphorus or arsenic as donor atoms
- 1 January 1969
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc. A
- p. 2904-2910
- https://doi.org/10.1039/j19690002904
Abstract
Four tripod-like ‘hybrid’ ligands (L) with donor sets N3P, N3As, N2P2, and N2As2 have been synthesized. They form cobalt(II) and nickel(II) complexes of general formula [MLX]Y (X = Cl, Br, I, CN, or NCS; Y = BPh4 or I) and [ML(NCS)2]. The cobalt(II) complexes are high-spin five-co-ordinate. The nickel(II) complexes with ligands N3P and N3As are either high-spin five-co-ordinate or low-spin, probably square-planar. With the ligand N2P2, low-spin, five-co-ordinate nickel(II) complexes are formed. The magnetic cross-over point for five-co-ordinate complexes of nickel(II) is found on changing from the N3PX to the N2P2X donor set. In the bisthiocyanato-complexes with N3P and N3As the phosphorus and arsenic atom are un-co-ordinated. The octahedral [Ni(N2As2)(NCS)2] complex gives rise to an equilibrium between octahedral and five-co-ordinate species in solution.Keywords
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