Magnetic properties of 4,4′-bipiperidinediium tetrahalocuprates: crystal structures of 4,4′-bipiperidinediium tetrabromocuprate(II) monohydrate and bis(4,4′-bipiperidinediium) hexabromodicuprate(I)
Reaction of 4,4′-bipiperidine (bipip) with copper(II) bromide in aqueous HBr yielded the salts (H2bipip)CuBr4·H2O (2) and (H2bipip)2Cu2Br6 (3). Compound 2 crystallizes in the
space group P2
/m and forms alternating layers of the H2bipip cations and CuBr4 anions with the water molecules located in the anionic layer. Compound 3 contains Cu(I) and crystallizes in the space group P2
and comprises stacks of H2bipip cations alternating with stacks of anions. Temperature-dependent magnetic measurements
on 2 and its chloride analog, 1, show distinctly different behaviors supported by the two-halide superexchange pathway. The chloride compound (1) is best described as weakly interacting antiferromagnetic dimers (J ~ −13 K), while the bromide
compound (2) exhibits very weak ferromagnetic interactions best modeled as a uniform chain with J = 2.45 (9) K (using the H = −J
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Document Type: Research Article
Department of Chemistry, University of Canterbury, Christchurch, New Zealand
Department of Chemistry, Howard University, Washington, DC, USA
School of Chemical Technology, Aalto University, Aalto, Finland
Carlson School of Chemistry and Biochemistry, Clark University, Worcester, MA, USA
January 2, 2016