Microwave-Assisted Synthesis of a Series of Lanthanide Metal-Organic Frameworks and Gas Sorption Properties

A series of isostructural microporous lanthanide metal organic frameworks (MOFs) formulated as [Ln(2)(TPO)(2)(HCOO)]center dot(Me2NH2)center dot(DMF)(4)center dot(H2O)(6) {Ln = Y (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Ho (7), Er (8), Tm (9), Yb (10), and Lu (11); H3TPO = tris-(4-carboxylphenyl)phosphinemdde; DMF = N,N-dimethylformamide} has been synthesized under microwave-assisted solvothermal reaction for 30 min. Alternatively, if a conventional solvothermal reaction is carried out under the same temperature, a much longer time (3 days) is needed for the same phase in similar yield. Structure analysis reveals that the framework is a 4,8-connected network with point symbol (4(10).6(16).8(2)) (4(5).6)(2), which is the subnet of alb net. Thermal gravimetric analyses performed on as-synthesized MOFs reveal that the frameworks have high thermal stability. The luminescent properties of 2, 3, 5, and 6 were investigated and show characteristic emissions for Sm(III), Eu(III), Tb(III), and Dy(III) at room temperature, respectively. Gas sorption properties of 1 and 3 were studied by experimentally measuring nitrogen, argon, carbon dioxide, methane, and hydrogen sorption isotherms. The resulting materials show high and preferential CO2 adsorption over N-2 gas at ambient temperature, indicating that the present materials can be applied in a CO2 capture process.