Syntheses, Structures, Photoluminescence, and Gas Adsorption of Rare Earth–Organic Frameworks Based on a Flexible Tricarboxylate

Three new organic-lanthanide frameworks based on a flexible H3L acid, namely, [Er3(L)3(H2O)4]·5.64H2O (1), [Dy3(L)3(H2O)4]·2H2O (2), and [Tb3(L)3(H2O)4]·2H2O (3), where H3L = 5-(benzonic-4-ylmethoxy)isophthalic acid, have been synthesized under mild solvothermal conditions. Compounds 1–3 are isostructural, in which L ligands linked the lanthanide(III) ions (M) to generate two kinds of cages, [M2L]6 and [M2L2]12. These cages are further connected through sharing the M(III) atoms to yield a 3D framework with 1D channels. Topologically, the 3D framework belongs to a binodal (3,6)-connected net with the point symbol of (42.6)(44.62.86.103). Furthermore, compounds 1 and 2 display interesting emissions in the near-IR regions. Compound 3 exhibited strong green luminescence upon 249 nm excitation. The adsorption property of 1 has also been investigated.