Two New Piperazine Templated Lanthanide Sulfates with 2D Corrugated Layered Crystal Structures

Two new piperazine templated lanthanide sulfates (C₄N₂H₁₂)_1.5Ln(SO₄)₃(H₂O)]·H₂OLn=Gd(1), Tb(2)] have been synthesized solvothermally and structurally characterized by single crystal X-ray diffraction(XRD), infrared(IR) spectroscopy, thermal analysis, fluorescent spectra and inductively coupled plasma(ICP). Single crystal X-ray diffraction reveals that both compounds 1 and 2 crystallized in the monoclinic crystal system, with space group P2₁/c and cell dimensions: a=0.64468(19) nm, b=2.9979(9) nm, c=0.9818(3) nm, β=101.271(4)°, V=1.8608(10) nm³, Z=4 for compound 1; a=0.64259(19) nm, b=3.0010(9) nm, c=0.9812(3) nm, β=101.229(4)°, V=1.8560(10) nm³, Z=4 for compound 2. Compounds 1 and 2 are isomorphous and have similar 2D corrugated inorganic frameworks fabricated via the connection of single chains and S2O₄ groups, while fully protonated piperazine cations and water molecules are located between the inorganic layers. The solid state luminescent properties of compound 2 were investigated and it displayed a typical luminescent property of Tb³⁺ with excitation wavelength at 371 nm.