Synthesis and Characterization of a Di-µ-oxalato Tetracopper(II) Complex with Tetranucleating Macrocyclic Ligand

• Published in: Bulletin of the Chemical Society of Japan Vol. 89; no. 4; pp. 430 - 436
• Main Authors: Miyazato, Yuji, Asato, Eiji, Ohba, Masaaki, Wada, Tohru
• Format: Journal Article
• Language: English
• Published: TOKYO The Chemical Society of Japan 15.04.2016; Chemical Soc Japan; Chemical Society of Japan
• Subjects: Anion exchanging; Antiferromagnetism; Chemistry; Chemistry, Multidisciplinary; Diffraction; Holes; Ligands; Macrocyclic compounds; Methyl alcohol; Oxalates; Physical Sciences; Science & Technology; Sodium; COORDINATION CHEMISTRY; BRIDGED COPPER(II); SERIES; ARRANGEMENT; RAY CRYSTAL-STRUCTURES; IONS; MAGNETIC-PROPERTIES; ZINC(II); 1,4,7-TRIAZACYCLONONANE; NICKEL(II)
• ISSN: 0009-2673; 1348-0634
• DOI: 10.1246/bcsj.20150338

A tetracopper(II) complex containing two oxalate anions in the metal-based host cavity, [Cu4(Lpy)(µ-ox)2](PF6)2·2(2-PrOH), where ox2−: oxalato (C2O42−), was prepared by reacting H2Lpy, a phenol-based tetranucleating macrocyclic ligand with four pyridylmethyl pendant arms, Cu(ClO4)2·6H2O, and sodium oxalate (1:4:2 stoichiometry, respectively) in methanol, followed by exchange of the counteranion with excess of NH4PF6. Single-crystal X-ray diffraction of 1 revealed that two {Cu(II)Cu(II)} units, bridged by a phenolato group of Lpy2−, were connected by two oxalato anions, to construct a rectangular “{CuCu}(µ-ox)2{CuCu}” tetranuclear framework. This rectangular framework was maintained in DMF solution. The magnetic measurement of 1 in the 2–300 K range revealed antiferromagnetic behavior. The antiferromagnetic interaction in this complex occurs between the Cu(II) centers bridged by an oxalate (J = −140 cm−1).