Synthesis, structures and properties of cobalt(II) and copper(I) complexes of 2,6-diamino-3-[(2-carboxymethyl)phenylazo]-pyridine

The reaction of methyl anthranilate, sodium nitrite, and 2,6-diamino-pyridine affords a new compound, 2,6-diamino-3-[(2-carboxymethyl) phenylazo]-pyridine (L), which has been characterized with X-ray crystallography and NMR spectrum. The reaction of L and CoCl2⋅ 6H2O or Cu(ClO4)2⋅ 6H2O gives a dinuclear cobalt(II) complex [Co2L2Cl3]Cl (1), and a copper(I) complex [CuL2]ClO4 (2)，respectively. They are characterized by X-ray crystallography, X-ray photoelectron spectroscopy, NMR spectra, magnetic measurement and emission spectra. Magnetic behavior of 1 denotes the occurrence of intramolecular antiferromagnetic interactions (J = − 141.8 cm− 1). Complex 2 exhibits photoluminescence at 557 nm.