Octacyanotungstate(v)-based square W2M2 (M = Co, Mn) complexes: synthesis, structure and magnetic properties

Abstract

The preparation, single-crystal X-ray crystallography and magnetic properties are reported for two tetranuclear cluster complexes based on [W^V(CN)₈]³⁻ octacyanometallates. Reactions of [W^V(CN)₈]³⁻ with Co^II ions in the presence of the capping ligand tpm (tpm = tri(1H-pyrazol-1-yl)methane) lead to the formation of complex 1 [(tpm)₂Co^II][W^V₂(CN)₁₆Co₂(tpm)₂(H₂O)₂]·4H₂O. Analogous reactions with the Mn^II produce complex 2 [(tpm)₂Mn^II][W^V₂(CN)₁₆Mn₂(tpm)₂(H₂O)₂]·4H₂O. Complexes 1 and 2 are isomorphous and crystallize in the space group of P. Magnetic investigation shows the ferromagnetic coupling between Co^II and W^V ion in complex 1, while the antiferromagnetic interactions between Mn^II and W^V in complex 2. Further magnetic studies indicate the presence of spin glasses in complex 2, which may be attributed to the further ferromagnetic coupling between anionic and/or cationic cores.