Four new Co(II) complexes with 2-amino-4-methylpyridine, 2-amino-3-methylpyridine, or 2-amino-5-chloropyridine: synthesis, spectroscopy, magnetic properties, and crystal structure

Abstract

Solid-state structures for a series of [Co(L)₂X₂] complexes are assigned on the basis of magnetic moments, FTIR spectra, electronic spectra properties (L = 2-amino-4-methylpyridine, 2-amino-3-methylpyridine, or 2-amino-5-chloropyridine; X = chloride or acetate). All complexes were prepared in one-step syntheses. The crystal structure of 2-amino-4-methylpyridine with cobalt(II) chloride [Co(L)₂(Cl)₂] was solved at room temperature. This compound consists of mononuclear units consisting of two ligands linked to cobalt via the pyridine. The complex crystallizes in the orthorhombic system, space group Pcan with z = 8. UV-Vis spectra show five absorption bands, attributed to d–d transitions of cobalt, ligand → metal charge transfer, and π → π* or n → π* transitions of ligand. FTIR spectra show CoL₂X₂ vibrations at 550–300 cm⁻¹. The compounds show room temperature magnetic moments of 4.58–5.29 B.M., indicating high-spin cobalt(II).

Keywords:

• Cobalt(II) complexes
• Crystal structure of cobalt(II)
• Magnetic moment of cobalt(II)

Acknowledgments

The authors thank the Research Council of Arak University for financial support of this research.