A new series of Schiff base Ni(II)4 cubanes: Evaluation of magnetic coupling via carboxylate bridges.

The Schiff base ligand H2L has been synthesized by condensation of 2-aminophenol with 3-methyl-1-phenyl-4-formylpyrazol-5-one and reaction between H2L and Ni(OOCR3)2, R = H in 1, –CH3 in 2, Cl in 3, yielded three new tetranuclear Ni(II) complexes. The complexes have been characterized by elemental analysis, IR- and ES-MS spectroscopy. Their structures as well as structure of ligand were determined by single-crystal X-ray diffraction. Compounds 1–3 possesses tetranuclear cubane-like structures containing [Ni4L4(R3COO)2]2 complex anions, which are charge balanced by two triethyl ammonium cations. Furthermore, the crystal structure of the Ni(II) cubane compound containing trichloroacetate bridging ligands, is reported for the first time. Variable temperature magnetic susceptibility measurements revealed interplay between ferromagnetic and antiferromagnetic exchange in the tetranuclear cubane-like compounds 1–3, in which ferromagnetic interactions were enhanced by introducing carboxylate bridging groups. DFT calculations supported the analysis of magnetic data.

Keywords

Ni(II) complex, Schiff base, Cubane-like structures, X-ray diffraction, Magnetic properties

Citation

POLYHEDRON. 2021, vol. 196, issue 1, p. 1-8.
https://www.sciencedirect.com/science/article/pii/S0277538720306744

Document type

Peer-reviewed

Document version

Published version

Language of document

en

Document licence

Creative Commons Attribution 4.0 International
http://creativecommons.org/licenses/by/4.0/