A series of 3-D lanthanide coordination polymers constructed from dinuclear building blocks: Synthesis, structure, thermal stability, and fluorescent properties

Abstract

A series of novel coordination polymers [Ln 2(NIPH) 2(Suc)(H 2O) 2] [Ln = Tb( 1), Eu( 2), Gd( 3), Dy( 4), Ho( 5), Er( 6), Tm( 7) and Y( 8); H 2NIPH = 5-nitroisophthalic acid; H 2Suc = succinic acid] have been synthesized by the reaction of nitrate salts of Ln (III) with 5-nitroisophthalic acid and succinic acid under hydrothermal conditions and were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Structural analyses reveal that all eight complexes have 3-D structures, and in these complexes, they were crystallized in monoclinic space group C2/c. Two crystallographically equivalent Ln atoms are bridged by two especial carboxylate groups in chelating/bridging bidentate fashion to give a dinuclear lanthanide building block [Ln 2O 2(CO 2R) 8] with shorter separations of Ln···Ln. Those blocks are interconnected to each other leading to a 1-D infinitely extending chain, and then these chains are linked to each other through the NIPH to a 2-D open framework, which further link to each other to form 3-D networks. The thermogravimetric analysis of 1– 8 and photoluminescent properties of 1 and 2 are discussed in detail.