Preparation of Crystalline Phases of 3D Coordination Polymers Based on Tetracarbonatodiruthenium Units and Lanthanide(III) Ions – Magnetic Characterization

Abstract

Attempts to obtain pure crystalline phases of heteropolynuclear diruthenium–lanthanide complexes were made through four different experimental procedures: a conventional method, solvothermal synthesis, solvothermal synthesis assisted by microwave irradiation and layering synthesis. The complexes [Ln(H2O)4][Ru2(CO3)4(H2O)]·xH2O [Ln = Gd, x = 2.5 (1); Ln = Nd, x = 4 (2); Ln = Eu, x = 2.25 (3); Ln = Yb, x = 2.5 (4)] were obtained in good yields through the different procedures, but the layering method was the best to yield single crystals of 1, 3 and 4. In the solvothermal synthesis of 1, the minor product K3[Gd(H2O)4]2[Ru2(CO3)4]3·3.5H2O (5) was also obtained in a very low yield. The crystal structures of the three‐dimensional compounds 1 and 3–5 were determined by single‐crystal X‐ray diffraction, and two different structural types were found for the Gd derivatives. The magnetic properties of 1, 2 and 4 were fitted with an equation including the sum of the molar susceptibilities of the diruthenium unit and the lanthanide ion. However, the fit of the magnetic properties of 3 requires the consideration of the existence of the splitting of the 7F ground‐state term by spin–orbit coupling. This study shows that the magnetic behaviours of 1, 2 and 4 are governed by weak antiferromagnetic interactions between the diruthenium units and the lanthanide ions.