Crystal structure and linear chain antiferromagnetism in Mn(tricyanomethanide)2(4,4′-bipyridine)2

A new linear chain antiferromagnet, namely Mn(tcm)2(4,4′-bipy)2 (tcm=tricyanomethanide and bipy=bipyridine) has been synthesized and characterized by X-ray crystallography and magnetic susceptibility measurements. Each Mn2+ is high-spin S=5/2 and linked to nearest-neighbor spin sites via μ-bridged tcm ligands to form a 1D linear chain while the bipy ligands are monodentate and segregate the chains. Magnetically, a broad maximum in χ′(T) is observed at 2.1 K and likely signifies short-range magnetic order within the chains. A least-squares fit of the χT(T) data to a classical-spin Fisher chain model yielded good agreement for g=2.008(1) and J=−0.217(4) K. No long-range magnetic ordering is observed above 1.6 K due to the presence of very weak interchain magnetic interactions as indicated by inclusion of a mean-field model that gave zJ′=−0.009(1) K.