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

Abstract

Two series of eight polycarboxylate lanthanide coordination complexes, namely, [Ln(cpia)(H 2 O) 2 ]·4H 2 O {Ln = Ce ( 1 ), Nd ( 2 ), and Sm ( 3 )} and [Ln(cpia)(H 2 O) n ] 2 ·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.