Publication in Inorganic Chemistry

A Series of Solution-Stable Heterometallic Molecular Phosphonates with {Co₉Dy}, {Co₇Dy}, and {Co₆Dy} Cores

Authors: Iaroslav Doroshenko, Tomas Pokorny, Lucie Simonikova, Zdenek Moravec, Jaromír Marek, Ján Vančo,
Zdeněk Trávníček, and Jiri Pinkas

Full-text: https://doi.org/10.1021/acs.inorgchem.6c01194

 

A family of three heterometallic molecular phosphonate cluste {Co_xDy} (x = 6, 7, 9) cores was synthesized using the Schiff-base-derived phosphonate ligand HSAA2−. The reactions of CoCl₂·6H₂O and DyCl₃·6H₂O with HSAA2− under various conditions afforded the polynuclear complexes [Co₉Dy(SAA)₆Cl₃] (1), [Na₂Co₇Dy(SAA)₆(SA)] (2), and [Na₃Co₆Dy(SAA)₆] (3), which are based on a common {Co₆Dy}  phosphonate core further stabilized by additional cobalt or sodium cations. The complexes were found to be thermally stable up to 250 °C, soluble, and stable in polar aprotic solvents. Direct current (dc) magnetic susceptibility measurements recorded over the temperature range 2−300 K were interpreted using an effective- spin model. The analysis revealed an isotropic Co2+ contribution and a strong axial Dy3+ response consistent with Ising-type magnetic behavior. Despite the presence of strongly anisotropic Dy3+ centers, alternating current (ac) magnetic measurements revealed negligible slow relaxation of magnetization, even under an external magnetic field.

 

 

A Series of Solution-Stable Heterometallic Molecular Phosphonates with {Co9Dy}, {Co7Dy}, and {Co6Dy} Cores