Ferroelastic-like transition and solvents affect the magnetism of a copper-organic radical one-dimensional coordination polymer.

The one-dimensional coordination polymers {[Cu II (hfac) 2 ] 3 ( m -BNN)} n · n CH 2 Cl 2 (1 ·CH 2 Cl 2 , P 1̄) and {[Cu II (hfac) 2 ] 3 ( m -BNN)} n (1', P 2/ n ), hfac = hexafluoroacetylacetonate and m -BNN = meta -phenylene bis(nitronyl-nitroxide), were obtained from CH 2 Cl 2 and CHCl 3 , respectively. 1 ·CH 2 Cl 2 is transformed to 1 at 335 K. Their magnetic susceptibilities differ in both magnitude and temperature dependence behavior. 1 and 1' undergo a ferroelastic-like phase transition at 110 K and an unidentified one at 37 K. There is a subtle long relaxation of this ferroelastic-like ordered state.