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.

Tetracarbonatodiruthenium Fragments and Lanthanide(III) Ions as Building Blocks to Construct 2D Coordination Polymers

“…Moreover, we also prepared [Ln(OH 2 ) 4 ][Ru 2 (CO 3 ) 4 (OH 2 )]·xH 2 O (Ln = Pr ( Pr3D ), Sm ( Sm3D )) for comparative reasons. These complexes display a 3D polymeric structure and they are isostructural to the Gd, Eu and Yb derivatives that were previously reported by our research group [21]. The magnetic properties and crystal structures of the new complexes are described in this paper.…”

“…Two of the carbonate ligands, in trans disposition, of the [Ru 2 (CO 3 ) 4 (DMSO) 2 ] 3− bridge a Pr 3+ ion and two ruthenium atoms with a µ 3 -1κ O ,2κ O′ , 3 κ O″ coordination mode (Figure 4, center). The Ru–Ru distances are 2.264 and 2.258 Å, which are in the range 2.238–2.272 Å found for other tetracarbonatodiruthenium compounds [2,10,13,16,18,20,21]. The Pr 3+ ions have a coordination number of nine and are surrounded by the three oxygen atoms of water molecules, two oxygen atoms of DMSO molecules and 4 oxygen atoms of 3 carbonate ligands (Figure 4, right).…”

“…As previously reported, the equimolecular reaction of K 3 [Ru 2 (CO 3 ) 4 ]·4H 2 O and Ln(NO 3 ) 3 ·xH 2 O in water under different conditions (direct mixture, layering synthesis or solvothermal synthesis with or without microwave radiation) leads to the formation of 3D structures with [Ln(OH 2 ) 4 ][Ru 2 (CO 3 ) 4 (OH 2 )]·xH 2 O composition [21]. This approach has been also successfully employed to prepare Pr3D and Sm3D in this work.…”

“…The α structure has a significantly lower density (2.142 g·cm − 3 ) than the β structure (2.447, 2.426 g·cm − 3 , Table 1). The structure of [Sm(OH 2 ) 4 ][Ru 2 (CO 3 ) 4 (OH 2 )]·2H 2 O ( Sm3D ) was determined by single crystal X-ray diffraction and is isostructural to the previously reported Gd, Eu and Yb derivatives (See Figures S3–S5) [21]. The PXRD of [Pr(OH 2 ) 4 ][Ru 2 (CO 3 ) 4 (OH 2 )]·2H 2 O ( Pr3D ) shows that it is isostructural with Sm3D (See Figure S6).…”

“…However, very recently the formation of single crystals of the complexes [Ln(OH 2 ) 4 ][Ru 2 (CO 3 ) 4 (OH 2 )]·xH 2 O [Ln = Gd, Eu, Yb] and K 3 [Gd(H 2 O) 4 ] 2 [Ru 2 (CO 3 ) 4 ] 3 ·3.5H 2 O has been achieved. The resolution of the crystal structures of these compounds shows in all cases the formation of 3D coordination polymers [21].…”