2D and 3D networks of lanthanide with mixed dicarboxylate ligands: syntheses, crystal structures and photoluminescent properties

Abstract

A series of lanthanide complexes with mixed polycarboxylate ligands, [Ln₂(op)₂(ox)(H₂O)₄]_n·nH₂O (Ln = Ce, Pr, Nd, Sm, Eu and Gd for 1–6, respectively), [KLn(pma)_1/2(ox)(H₂O)]_n (Ln = Tb (7) and Dy (8)), [KLn₂(mp)₃(ox)_1/2(H₂O)₃]_n (Ln = Ce(9) and Pr(10)) (op = o-phthalate, ox = oxalate, pma = pyromellitate and mp = m-phthalate), have been prepared, and their photoluminescent properties have been investigated. Compounds 1–6 show (3,4)-connected 2D network structures consisting of {Ln(op)}_n staircase chains bridged by ox ligands. Compounds 7 and 8 consist of 1D zigzag {Dy(ox)}_n chains linked by pma ligands adopting a new μ₄-hexadentate coordination mode to form 2D 6-connected networks with (3⁶·4⁶·5³) topology. Through K⋯O interactions, the 2D networks are further connected to construct 3D structures. Compounds 9 and 10 display inorganic–organic 3D topology networks with the Schläfli symbol (3·4³·5²)(3²·4¹⁰·5⁹·6¹⁴·7)(4²·5) containing mixed (3,4,9)-connected nodes.