Humidity-Induced Switching between Two Magnetic and Structural Phases in a Co -[W (CN) ] Molecular Magnet.

The self-assembly of cobalt(II) with purine and octacyanidotungstate(V) results in the formation of the three-dimensional Co [W(CN) ] (purine) ⋅8.5H O (1) coordination polymer. This compound exhibits humidity-induced variation of the number of water molecules of crystallisation leading to a reversible structural phase transition and the alternation of the long-range ferromagnetic ordering temperature from T =29 K for the pristine assembly (1) to T =49 K for the sample stored in a low-humidity atmosphere (1-deh).