Copper(II) complexes of N,N′-dimethylethane-1,2-diamine with fluoride and tetrafluoroborate: syntheses, structures, and magnetic properties

Abstract

[Cu(bmen)₂(H₂O)₂]F₂∙4H₂O (1) (bmen = N,N′-dimethylethane-1,2-diamine) and [Cu(bmen)₂(BF₄)₂] (2) exhibit ionic and molecular crystal structures, respectively. In both 1 and 2, Cu(II) exhibits tetragonally elongated six coordination in the 4 + 2 form with two chelate bmen in the equatorial plane; axial positions are occupied by weakly bound water in 1 while in 2 in these positions are fluorine from disordered BF₄ ⁻. Packing in 1 and 2 are governed by hydrogen bonds (HBs). Magnetic studies from 1.8 to 300 K reveal that 1 and 2 follow the Curie–Weiss law with parameters θ = −0.88 K and g = 2.04 for 1 and θ = −0.58 K and g = 2.13 for 2, suggesting the presence of weak antiferromagnetic interactions.

Keywords:

• Copper(II)
• Crystal structure
• Hydrogen bond
• Magnetic studies
• Fluorine

Acknowledgements

This work was supported by the Slovak grant agency VEGA (Grant Nos. 1/0089/09 and 1/0078/09), Slovak Research and Development Agency (Grant No. APVV-0132-11), SAS Center of Excellence: CFNT MVEP and ERDF EU (European Union European regional development fond) grant, under the contract No. ITMS26220120047. J.H. thanks the support from P.J. Šafárik, University in Košice, Faculty of Sciences Student grant (VVGS 1/12-13). Material support from US Steel – DZ Energetika Košice is greatly acknowledged. We thank M. Kajňaková for SQUID data collection.