Synthesis, structure and magnetic properties of catena-diaqua-bis(pyridine-N-oxide)(μ-pyrazine)copper(II) perchlorate and the monomeric structure tetrakis(pyridine-N-oxide)copper(II) perchlorate

• Published in: Journal of coordination chemistry 2020-12, Vol.74 (1-3), p.266-278
• Main Authors: Landee, Christopher P., Kirkman-Davis, Emma, Polson, Matthew I. J., Turnbull, Mark M., Wikaira, Jan L.
• Format: Article
• Language: English
• Subjects: antiferromagnet; Coordination compounds; Coordination polymers; Copper; Copper compounds; Cu(II); EPR; magnetic chain; Magnetic permeability; Magnetic properties; Single crystals; Synthesis; X-ray
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2020.1856825

Reaction of copper(II) perchlorate with pyrazine and pyridine-N-oxide produced the coordination polymer catena-[diaqua-μ-pyrazine-bis(pyridine-N-oxide)copper(II)] perchlorate (1) which was characterized by single-crystal X-ray diffraction, EPR and variable temperature magnetic susceptibility measurements. The compound forms well-isolated linear chains, bridged by pyrazine. EPR studies show a rhombic structure with g ave = 2.15. The magnetic data are well described by the uniform Heisenberg chain model giving J/k B = −9.6(1) K and show no signs of inter-chain interactions down to 1.8 K [H = −JΣS 1 S 2 ]. In the course of the synthesis, the related [tetrakis(pyridine-N-oxide)copper(II)] perchlorate complex (2) was also isolated. X-Ray studies confirm the identity of the compound in comparison to the previous literature. EPR studies indicate a rhombic structure, similar to 1, but variable temperature magnetic susceptibility data show no significant magnetic exchange in agreement with the absence of a superexchange pathway in the crystal.