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A Tetranuclear Hydroxo‐Bridged Copper( II ) Complex with Primary N‐ Acylamidines as Ligands: Preparation, Structural, and Magnetic Characterisation
Author(s) -
Eberhardt Jan K.,
Glaser Thorsten,
Hoffmann RolfDieter,
Fröhlich Roland,
Würthwein ErnstUlrich
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200400779
Subject(s) - chemistry , copper , crystallography , cubane , ligand (biochemistry) , acetonitrile , hexafluorophosphate , ion , magnetic susceptibility , stereochemistry , crystal structure , organic chemistry , catalysis , biochemistry , ionic liquid , receptor
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 ](PF 6 ) 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)