Synthesis, Structures, and Properties of Lanthanide Complexes with Pyrimidine‐2‐carboxylic Acid

Abstract

Six lanthanide complexes [Ln(pmc) 2 NO 3 ] n [Hpmc = pyrimidine-2-carboxylic acid, Ln = La (1), Pr (2)], [Ln(pmc) 2 (H 2 O) 3 ]NO 3 ·H 2 O [Ln = Eu (3), Tb (4) Dy (5), Er (6)] were synthesized by the reactions of lanthanide nitrate and pyrimidine-2carboxylic acid in water at room temperature. These complexes were characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR, circular dichroism (CD) and fluorescence spectra. Structure analysis shows that complexes 1 and 2 are isostructural with P4 3 2 1 2 space group, whereas isostructural complexes 3-6 belong to the P2 1 /c space group. In complexes 1 and 2, the central metal atoms * Dr. J. Xia E-Mail:xiajun@tjpu.edu.cn [a] School of Environment and Chemical Engineering

Magnetic and Luminescent Properties of Isostructural 2D Coordination Polymers Based on 2-Pyrimidinecarboxylate and Lanthanide Ions

“…Coordination polymers (CPs) are defined as infinite systems built up from metal ions and organic ligands linked via coordination bonds and other weak chemical bonds such as hydrogen bonds, π-π stacking, or van der Waals interactions [1]. These materials have gained considerable attention in recent decades, in particular, lanthanide-based coordination polymers, due to their varied structures [2,3], high coordination numbers, gas storage properties [4], biochemical and medical applications [5], as well as interesting luminescent [6] and magnetic properties [7][8][9]. The key factor for the synthesis of CPs is to choose appropriate metal centers and bridging ligands to obtain the desired topologies and properties, although other factors can also have an influence such as metal-to-ligand ratio, temperature, pH value, and solvents [10,11].…”

“…Ligands such as pyridylcarboxylate, imidazolylcarboxylate, pyrimidylcarboxylate, or indolylcarboxylate derivatives are used extensively in coordination chemistry based on lanthanide ions [15][16][17]. Specifically, we chose the ligand pyrimidine-2-carboxylate (pymca), which contains both oxygen and nitrogen coordination atoms (Scheme 1), because, to date, only a few structures based on rare-earth ions and this ligand have been reported, all of them by Wang et al [8]. Inspired by all the above-mentioned ideas, we decided to react pymca and lanthanide ions with the objective of building coordination polymers with interesting luminescent and magnetic properties, due to the fact that, fifteen years ago, we were the pioneers to design and work with this novel ligand, which shows great ability to form two-dimensional and three-dimensional coordination polymer compounds.…”

Synthesis, Structures and Properties of Two Ln(III) Coordination Polymers based on Pyrimidine‐2‐carboxylic Acid and Sodium Dicyanamide

“…[19] Some research work about Hpmc had also been performed in our group, and a series of lanthanide complexes with 2D and 3D structures were obtained. [20] In this paper, we employed sodium dicyanamide as a flexible co-ligand to react with Hpmc and samarium nitrate or europium nitrate, and two novel lanthanide complexes, [Ln (pmc) 2 (dca)(H 2 O) 2 ] n (Ln=Sm (1), Eu (2)), were synthesized and structurally characterized by single crystal X-ray analyses. 1 and 2 are isostructural with the space group of C2/c and the central metal atoms have the same nine coordination number, which exhibit a 1-dimensional zigzag chain through pmc À bridges.…”

“…Compared with these neutral and rigid ligands, dicyanamide anion (dca − ) has the flexible nature to exhibit much more coordination modes (monodentate, μ 1,3 ‐ and μ 1,5 ‐bidentate bridges, μ 1,3,5 ‐tridentate), which could possibly influence both components and arrangements of complexes and result in fascinating conformations of coordination polymers [19] . Some research work about Hpmc had also been performed in our group, and a series of lanthanide complexes with 2D and 3D structures were obtained [20] …”