AUTHOR=Hussain Sajjad , Chen Xuenian , Harrison William T. A. , Elsegood Mark R. J. , Ahmad Saeed , Li Shujun , Muhammad Shabbir , Awoyelu David TITLE=Synthesis, Crystal Structures and Photoluminescent Properties of One-Dimensional Europium(III)- and Terbium(III)-Glutarate Coordination Polymers, and Their Applications for the Sensing of Fe3+ and Nitroaromatics JOURNAL=Frontiers in Chemistry VOLUME=7 YEAR=2019 URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00728 DOI=10.3389/fchem.2019.00728 ISSN=2296-2646 ABSTRACT=

Two lanthanide–glutarate coordination polymers, viz. : {[Eu(C₅H₆O₄)(H₂O)₄]Cl}_n, (1) and [Tb(C₅H₇O₄)(C₅H₆O₄)(H₂O)₂]_n, (2) have been synthesized and characterized by IR spectroscopy, thermogravimetric analysis, and X-ray crystallography. In 1, the Eu(III) ions are coordinated by four O atoms from two bidentate chelating carboxylate groups, one O atom from a bridging carboxylate group and four O atoms from water molecules adopting an EuO₉ distorted tri-capped trigonal prismatic coordination geometry. In 2, the Tb(III) ions are coordinated by six O atoms from three bidentate chelating carboxylates, one O atom from a bridging carboxylate and two O atoms from water molecules to generate distorted tri-capped trigonal prismatic TbO₉ polyhedron. In both compounds, the metal polyhedra share edges, producing centrosymmetric Ln₂O₂ diamonds, and are linked into [001] chains by bridging glutarate di-anions. The crystal structures are consolidated by O–H···O and O–H···Cl hydrogen bonds in 1, and O–H···O hydrogen bonds in 2. Compound 1 exhibits a red emission attributed to the ⁵D₀ → ⁷F_J (J = 1–4) transitions of the Eu(III) ion, whereas 2 displays green emission corresponding to the ⁵D₄ → ⁷F_J (J = 0–6) transitions of the Tb(III) ion. Both the compounds exhibit high sensitivity and selectivity for Fe³⁺ ions due to luminescence quenching compared with other metal ions, which include; Na⁺, Mg²⁺, Al³⁺, Cr³⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Zn²⁺ and Cd²⁺. Compounds 1 and 2 also show high luminescence quenching sensitivity for 4-nitrophenol over the other aromatic and nitroaromatic compounds, namely; bromobenzene, 1,3-dimethylbenzene, nitrobenzene, 4-nitrotolune, 4-nitrophenol, 2,6-dinitrophenol and 2,4,6-trinitrophenol.