Rangsit Journal of Arts and Sciences. Vol.6 No.1 , January - June 2016.

Solvothermal synthesis, structure, and luminescent properties of a series of 3D lanthanide carbonate frameworks

Phailyn Khemthong, Filip Kielar, and Kittipong Chainok

Abstract

A series of three-dimensional (3D) lanthanide carbonate coordination polymers [Ln(μ₅-CO₃)(μ₂-OH)], Ln^III = Pr (1Pr), Nd (2Nd), Sm (3Sm), Eu (4Eu), Gd (5Gd), Tb (6Tb) and Dy (7Dy), has been synthesized using solvothermal conditions and characterized by spectroscopic methods.  Structures of compounds 1Pr-3Sm were solved from single crystal X-ray diffraction (SCXRD) data, whereas microcrystals of compounds 4Eu-7Dy were not of sufficient quality for SCXRD analysis.  Therefore, conventional powder X-ray diffraction (PXRD) and elemental analysis have been used to verify the phase purity. SCXRD analysis revealed that compounds 1Pr-3Sm are isostructural and crystallize in the orthorhombic space group Pnma with four formula units per unit cell.  In the crystal structure, each Ln^III cation is bridged by five μ₅-η²:η²:η²:η¹:η¹-CO₃²⁻ and two μ₂-OH⁻ ligands forming a neutral 3D framework.  The luminescence properties of compounds 4Eu and 6Tb were investigated in the solid state at room temperature.

Keywords: carbonate, crystallography, crystal structure, lanthanide, luminescence, solvothermal synthesis

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