A Tetranuclear Hydroxo-Bridged Copper(II) Complex with PrimaryN-Acylamidines as Ligands: Preparation, Structural, and Magnetic Characterisation

✍ Scribed by Jan K. Eberhardt; Thorsten Glaser; Rolf-Dieter Hoffmann; Roland Fröhlich; Ernst-Ulrich Würthwein

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 140 KB
• Volume: 2005
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/ejic.200400779

✦ Synopsis

Abstract

The reaction of N‐pivaloylbenzamidine (1a) and tetrakis(acetonitrile)copper(I) hexafluorophosphate in the presence of air yields a hydroxo‐bridged copper(II) complex (4). The product was characterised by X‐ray diffraction analysis and found to be a cubane‐like dimeric complex consisting of two square dimers with the formula {(1a)~2~Cu~2~(OH)~2~}~2~~4~·4 CH~2~Cl~2~ (4·4 CH~2~Cl~2~) with cupric ions and hydroxyl oxygen atoms at alternating vertices of a cube. The complex can be described as consisting of two [ligand‐Cu‐(OH)~2~‐Cu‐ligand] units held together by long out‐of‐plane Cu–O bonds, creating a tetrameric entity with a Cu~4~(OH)~4~ core. Each cupric ion is essentially square‐pyramidally coordinated, being bound to three OH bridges, one N atom of the amidine and one N‐acylamidine O atom. The magnetic properties of this compound have been studied in the 2–300 K temperature range. The measurements revealed that the cupric ions in the cube are antiferromagnetically coupled. This observation has been rationalised on the basis of the structural data. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)