Thermally induced crystal-to-crystal transformations accompanied by changes in the magnetic properties of a Cu-II-p-hydroquinonate polymer

In the Cu-II-p-hydroquinonate coordination polymer 1, the major pathway for antiferromagnetic exchange coupling runs along the hydroquinonate linker. Upon heating, 1 looses its supporting DMF ligands in a two-step sequence; the antiferromagnetic Cu-II-Cu-II interaction in the final product 3 is now mediated by two bridging oxygen atoms which results in an increase of the J value by two orders of magnitude.