Two Series of Luminescent Flexible Polycarboxylate Lanthanide Coordination Complexes with Double Layer and Rectangle Metallomacrocycle Structures

Two series of eight polycarboxylate lanthanide coordination complexes, namely, [Ln(cpia)(H2O)(2)]center dot 4H(2)O {Ln = Ce (1), Nd (2), and Sm (3)} and [Ln(cpia)(H2O)(n)](2)center dot 2H(2)O {Ln = Eu (4), Gd (5), Tb (6), Er (7), and Lu (8), n = 5 in 4-7; n = 4 in 8} {H(3)cpia = N-[4-(carboxymethoxy)phenyl]iminodiacetic acid}, have been synthesized by self-assembly and characterized by IR, thermogravimetric analysis, and X-ray crystallography. Complexes 1-3 are isomorphic featuring two-dimensional double layer structures, while the isomorphic complexes 4-8 exhibit [2 + 2] rectangle metallomacrocycle structures. Further, photoluminescence (PL) spectra of complexes 2, 4, and 6 show the strong characteristic luminescence of Eu(III), Tb(III), and Nd(III) ions, respectively, suggesting that cpia(3-) is able to efficiently sensitize the luminescence of lanthanide ions.