A lanthanide cluster formed by fixing atmospheric CO2 to carbonate: a molecular magnetic refrigerant and photoluminescent material

A lanthanide carboxylates cluster derived from 1,8-naphthalene dicarboxylate (NDC= 1,8 naphthalene dicarboxylate) and 1,10-phenanthroline (Phen) has been synthesized. The cluster of Sm(III) has been utilized for luminescence and magnetic refrigeration properties. Most interestingly, the auto immobilization of atmospheric carbon dioxide forms carbonate ion which acts as a bridging ligand and is positioned at the middle of the cluster. This cluster is characterized by different spectroscopic tools like FT-IR, photoluminescence spectrum, and the molecular structure [Sm₄(NDC)₅(Phen)₄(µ₄-CO₃)(H₂O)₃].3H₂O.CH₃OH (1) is determined by single crystals X-ray diffraction. π-conjugated ligand (NDC=1,8-Naphthalene dicarboxylate; Phen=phenanthroline) affects both absorption and photoluminescence intensity. Moreover, from the χ_mT vs temperature plot, it is observed that there is an occurrence of antiferromagnetic interaction among the Sm^III centers. The cluster possesses high magnetocaloric value at low temperature which offers itself as a potential candidate for cryogenic molecular magnetic refrigerant material. In addition, thermogravimetric analysis, Hirsh field surface area analysis, and the optical diffuse reflectance spectrum of this cluster is also described.

Graphical abstract

The synthesis, characterization, and magnetic properties of the Samarium cluster are described. The cluster is formed by the capturing of atmospheric CO₂ in the form of carbonate ions which connects all four metal centers. The cluster exhibits a high magnetocaloric effect for which it can be used for molecular magnetic refrigerant material. Besides this, it can be a potential candidate for luminescent materials.