The reaction of Co(AcO)2 with 6-methyl-2-pyridinecarboxylic acid, and that of CoCl2 with the isopropyl ester of 2-pyridinecarboxylic acid, both with a 1:2 metal to ligand molar ratio, afford optimum yields for the synthesis of cis-[Co(MeC5H 3NCOO)2(H2O)2] and cis-[CoCl 2(C5H4NCOOPri)2], respectively. According to X-ray crystallography they both consist of mononuclear discrete molecules with octahedral coordination around Co(II). The ESR powder spectra of the related Zn phases doped with 0.25% Co(II) show the strong anisotropy of the g and A tensors. The magnetic behaviour of the solid complexes is characteristic of Co(II) systems with important spin-orbit coupling and weak antiferromagnetic interactions. Electronic UV-Vis and magnetic data indicate that these complexes, as well as the already known trans-[Co(C5H4NCOO)2(H2O) 2], have a high-spin octahedral geometry in solution. © 2003 Elsevier B.V. All rights reserved.
- Antiferromagnetic interaction
- Cobalt complexes
- Crystal structures
- Picolinate ligand