Structural systematic design of organic templated samarium sulfates and their luminescence property

Abstract

Four organic amine templated samarium sulfates[(CH₃)₂NH₂]₉[Sm₅(SO₄)₁₂] 1, [NH₃(CH₂)₂NH₃]₄[Sm₂(SO₄)₇] 2, [H₃O]₂[(CH₃)₂NH₂][Sm(SO₄)₃] 3 and [(CH₃)₂NH₂]₃[Sm(SO₄)₃] 4 have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Compound 1 exhibits a 3D porous structure containing intersecting extra-large 20-membered ring channels; compound 2 is a 2D corrugated layered sulfate constructed by two different zigzag chains and 12-membered rings; compound 3 exhibits a 1D anionic chain structure compensated by protonated dimethylamine and water cations occluded in the helical [Sm–O–S]_n chains, and compound 4 is a novel 1D sulfate constructed by tetrameric [Sm₂(SO₄)₂O₁₀] unit and 4-membered rings. The syntheses of compounds 3 and 4 demonstrate that large organic amine (1,3,5-triazine-2,4,6-triamine or 4,4′-diaminobiphenyl) may be used as second structural directing agent (SDA) to prevent the formation of high dimensional inorganic framework as well as induce crystal growth of 1D chain structural samarium sulfate. The luminescent properties of compounds 1–4 were investigated. The strong luminescence of 3 in the orange light (598 nm ⁴G_5/2→⁶H_7/2) region indicates it is an excellent candidate for orange fluorescent materials.