Copper(II) Halide Salts with 1-(4′-Pyridyl)-Pyridinediium

Abstract

The compounds [1,4′-bipyridine]-1,1′-diium [CuCl4] (1) and [1,4′-bipyridine]-1,1′-diium [CuBr4] (2) were prepared and their crystal structures and magnetic properties are reported. The compounds are isomorphous and crystallize in the monoclinic space group C2/c. The cation crystallizes in a two-fold disordered fashion with the terminal nitrogen and carbon atoms exhibiting 50% occupancies. This results in a crystal packing arrangement with significant hydrogen bonding that is very similar to that observed in the corresponding 4,4′-bipyridinediium complexes. Temperature dependent magnetic susceptibility measurements and room temperature EPR spectroscopy indicate the presence of very weak antiferromagnetic exchange. The data were fit to the Curie−Weiss law and yielded Weiss constants of −0.26(5) K (1) and −1.0(1) K (2).

Keywords

• cu(ii)
• magnetism
• epr
• pyridine-based compound