Synthesis, crystal structure and magnetic properties of a novel tripeptide Schiff base heterotrinuclear complex with 1D supramolecular structure

Abstract

A novel tripeptide Schiff-base heterotrinuclear complex, [Co(H₂O)₄(CuL)₂]·4H₂O (1) (H₃L = N-5-bromosalicylideneglycylglycylglycine) has been synthesized and characterized by elemental analyses, IR and electronic spectra. Single-crystal X-ray diffraction analysis showed that the molecular structure is made up of centrosymmetrical trinuclear units with the Co atom lying on an inversion center. Through Cu ··· O and Cu ··· Br weak interactions and hydrogen bonds, the 1D supramolecular chain structure is formed. The magnetic susceptibility data (2–300 K) revealed antiferromagnetic interactions between copper(II) ions and the central metal cobalt(II) ions. The magnetic susceptibility data were quantitatively analyzed using the theoretical expressions deduced from the spin Hamiltonian for a symmetrical three-spin system to give the coupling J _CuCo = −2.26 cm⁻¹.

Keywords:

• Heterotrinuclear complex
• Tripeptide
• Weak interactions
• Crystal structure
• Magnetic properties

Acknowledgements

This work was supported by the National Natural Science Foundation of China and the PhD Programs Foundation of of Yangzhou University.