Pyrazine-2-carboxylate copper(II) complexes

Abstract

A pyrazine-2-carboxylate (pzCO₂) complex of copper(II) has been synthesized, studied structurally and magnetically, and compared with structurally similar compounds. The structure of [CuCl(pzCO₂)] (1) is reported and compared with the known structures of [Cu(pzCO₂)₂] (2) and [Cu(pzCO₂)₂(H₂O)₂] (3). Single-crystal X-ray diffraction measurements show that 1 crystallizes in the monoclinic space group Pc, with two crystallographically independent five-coordinate Cu(II) ions in a geometry close to square-pyramidal. It has a bilayer structure in the packing. Magnetic susceptibility data of 1 show that it exhibits weak ferromagnetic interactions (2 J = 2.26(7) K). In contrast, magnetic susceptibility data of 2 and 3 show weak antiferromagnetic interactions.

Keywords:

• Copper(II)
• magnetism
• pyrazinecarboxylate
• X-ray

Acknowledgements

AAM is grateful for support from an anonymous donor. We are grateful for funds from PCI Synthesis, part of SEQENS CDMO, toward the purchase of the D8 Focus diffractometer, from the National Science Foundation (IMR-0314773) for purchase of the MPMS SQUID magnetometer, and from the Kresge Foundation for both. Single crystal X-ray diffraction experiments for 1 were performed on a diffractometer at the University of Virginia funded by the NSF-MRI program (CHE-2018870).

Disclosure statement

No potential conflict of interest was reported by the authors.