Original scientific paper

Strong Antiferromagnetism in Isolated Anionic Dicopper(II) Methanoato Paddle-wheel Complex

Bojan Kozlevčar ; Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
Igor Kovšca ; Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
Zvonko Jagličić ; Institute of Mathematics, Physics and Mechanics & Faculty of Civil and Geodetic Engineering, University of Ljubljana, 1000 Ljubljana, Slovenia
Andrej Pevec ; Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
Nives Kitanovski ; Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
Peter Strauch ; Institute of Chemistry, University of Potsdam, 14476 Golm, Germany
Primož Šegedin ; Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia

Abstract

A new ionic compound (C_{5H6NO)2[Cu2(μ-O2CH)4(O2CH)2], 1 formed of 4-hydroxy-pyridinium cations and a complex anion was synthesized. The anion is a paddle-wheel dicopper carboxy-late complex with four syn,syn-bridging and two axial anionic methanoato ligands. The XRD structure de-termination of 1 reveals that the molecular structure is stabilized by two H-bonds between the cations and the axial paddle-wheel anions (N–H···O 2.755(3), O–H···O 2.489(2) Å). The compound exhibits a very strong (2J = 500 cm–1) intra-binuclear antiferromagnetic interaction noticed already at room temperature attributed to the methanoato intra-binuclear bridges. The typical EPR S = 1 spin system signals of the dicopper paddle-wheel complexes at 90 and 450–700 mT are found in the room temperature spectrum, but they are poorly seen in the 110 K spectrum. These signals are of very low intensity and are accompanied by a dominant signal at 320 mT, all closely related to a very strong antiferromagnetic interaction present in 1.}

Keywords

copper(II); methanoate; 4-hydroxypyridinium; dimer; antiferromagnet

Hrčak ID:

39693

URI

https://hrcak.srce.hr/39693

Publication date:

15.7.2009.

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