Solvothermal and Reflux Syntheses,Crystal Structure and Properties of Lanthanide-Thiophenedicarboxylate-Based Metal-Organic Frameworks

Abstract  

Two new lanthanide thiophenedicarboxylate-based metal-organic frameworks with the formulas La₂(2,5-TDC)₃(DMF)₂H₂O DMF (1) and Gd₂(2,5-TDC)₃(DMF)₂H₂O (2) (2,5-TDC = 2,5-thiophenedicarboxylic acid; DMF = N,N′-dimethylformamide), have been synthesized by two different methods (solvothermal and reflux). The synthesis of these materials from metal nitrate hydrates with 2,5-TDC as the organic linker in DMF/n-propanol afforded two rigid non-interpenetrating frameworks with coordinated solvent molecules (DMF and H₂O) occupying the channels. Compound (1) crystallizes in an orthorhombic space group Pna2₁ with Z = 4, a = 17.434(4) ?, b = 11.227(3) ?, c = 17.980(4) ? and V = 3,519.0(15) ?³. Compound (2) crystallizes in a monoclinic P2₁/n space group with Z = 4, a = 17.5387(17) ?, b = 10.8038(11) ?, c = 17.7283(18) ?, β = 104.793(2) and V = 3,247.9(6) ?³. Powder X-ray diffraction, thermogravimetric analysis and infrared spectroscopy of (1) and (2) are presented.