Tetracarbonatodiruthenium fragments and lanthanide(III) ions as building blocks to construct 2D Coordination Polymers

Abstract

Two-dimensional coordination polymers of [Pr(DMSO)2(OH2)3][Ru2(CO3)4(DMSO)(OH2)] ·5H2O (Prα) and [Ln(OH2)5][Ru2(CO3)4(DMSO)]·xH2O (Ln = Sm (Smβ), Gd (Gdβ)) formulae have been obtained by reaction of the corresponding Ln(NO3)3·6H2O dissolved in dimethyl sulphoxide (DMSO) and K3[Ru2(CO3)4]·4H2O dissolved in water. Some DMSO molecules are coordinated to the metal atoms reducing the possibilities of connection between the [Ru2(CO3)4]3- and Ln3+ building blocks giving rise to the formation of two-dimensional networks. The size of the Ln3+ ion and the synthetic method seem to have an important influence in the type of two-dimensional structure obtained. Slow diffusion of the reagents gives rise to Prα that forms a 2D net that is built by Ln3+ ions as triconnected nodes and two types of Ru25+ units as bi- and tetraconnected nodes with (2-c)(3-c)2(4-c) stoichiometry (α structure). An analogous synthetic procedure gives Smβ and Gdβ that display a grid-like structure, (2-c)2(4-c)2, formed by biconnected Ln3+ ions and two types of tetraconnected Ru25+ fragments (β structure). The magnetic properties of these compounds are basically explained as the sum of the individual contributions of diruthenium and lanthanide species, although canted ferrimagnetism or weak ferromagnetism are observed at low temperature.