Synthesis and structural characterization of 2Dioxane$\cdot$2H$_2$O$\cdot$CuCl$_2$: Metal-organic compound with Heisenberg antiferromagnetic S= 1 2 chains

A novel organometallic compound 2Dioxane$\cdot$2H$_2$O$\cdot$CuCl$_2$ (CuDCl) has been synthesized and structurally characterized by X-ray crystallography. Magnetic susceptibility and zero-field inelastic neutron scattering have also been used to study its magnetic properties. It turns out that this material is a weakly coupled one-dimensional S=1/2 Heisenberg antiferromagnetic chain system with chain direction along the crystallographic \textbf{c} axis and the nearest-neighbor intra-chain exchange constant \emph{J}=0.85(4) meV. The next-nearest-neighbor inter-chain exchange constant $J'$ is also estimated to be 0.05 meV. Unlike other compounds, the Cl concentration in CuDCl can be arbitrarily tuned by Br substitution. As a result, the strength of superexchange coupling \emph{J} changes dramatically with different Br concentrations \emph{x}.