A new series of Schiff base Ni(II)4 cubanes: Evaluation of magnetic coupling via carboxylate bridges. (1st March 2021)

• Record Type: Journal Article
• Authors: Gusev, Alexey N.; Nemec, Ivan; Herchel, Radovan; Baluda, Yuriy I.; Kryukova, Mariya A.; Efimov, Nikolay N.; Kiskin, Mikhail A.; Linert, Wolfgang
• Is Part Of: Polyhedron. Volume 196(2021)
• Publication Date: 2021-03-01
• Subjects: Ni(II) complex -- Schiff base -- Cubane-like structures -- X-ray diffraction -- Magnetic properties; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2020.115017
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Cubane-like Cu(II) complexes with – {[(2-hydroxyphenyl)amino]methylene}-5-methyl-2-phenyl-2, 4-dihydro-3H-pyrazol-3-one were synthesized. The tetranuclear structure of copper complexes was determined by XRS. The complex exhibits exchange interaction among the Cu(II) ions by a bridging carboxylate pathway. Relatively strong ferromagnetic exchange is triggered by the carboxylate-bridging ligands OOCR3 which strength is increasing in the order J(Me3 CCOO) < J(CH3 COO) < J(Cl3 CCOO). Abstract: The Schiff base ligand H2 L has been synthesized by condensation of 2-aminophenol with 3-methyl-1-phenyl-4-formylpyrazol-5-one and reaction between H2 L 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 [Ni4 L4 (R3 COO)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.