title: The new one-dimensional coordination polymer catena-poly[[diaquasodium(I)]-μ-oxalato-[diaquairon(III)]-μ-oxalato].
abstract: The oxalate dianion is one of the most studied ligands and is capable of bridging two or more metal centres and creating inorganic polymers based on the assembly of metal polyhedra with a wide variety of one-, two- or three-dimensional extended structures. Yellow single crystals of a new mixed-metal oxalate, namely catena-poly[[diaquasodium(I)]-μ-oxalato-κ(4)O(1),O(2):O(1'),O(2')-[diaquairon(III)]-μ-oxalato-κ(4)O(1),O(2):O(1'),O(2')], [NaFe(C2O4)2(H2O)4]n, have been synthesized and the crystal structure elucidated by X-ray diffraction analysis. The compound crystallizes in the noncentrosymmetric space group I41 (Z = 4). The asymmetric unit contains one Na(I) and one Fe(III) atom lying on a fourfold symmetry axis, one μ2-bridging oxalate ligand and two aqua ligands. Each metal atom is surrounded by two chelating oxalate ligands and two equivalent water molecules. The structure consists of infinite one-dimensional chains of alternating FeO4(H2OW1)2 and NaO4(H2OW2)2 octahedra, bridged by oxalate ligands, parallel to the [100] and [010] directions, respectively. Because of the cis configuration and the μ2-coordination mode of the oxalate ligands, the chains run in a zigzag manner. This arrangement facilitates the formation of hydrogen bonds between neighbouring chains involving the H2O and oxalate ligands, leading to a two-dimensional framework. The structure of this new one-dimensional coordination polymer is shown to be unique among the A(I)M(III)(C2O4)2(H2O)n series. In addition, the absorption bands in the IR and UV-Visible regions and their assignments are in good agreement with the local symmetry of the oxalate ligand and the irregular environment of iron(III). The final product of the thermal decomposition of this precursor is the well-known ternary oxide NaFeO2.
authors.affiliation: Laboratoire de Cristallographie-Thermodynamique, Faculté de Chimie, USTHB, BP 32 BEZ El Alia, Algiers 16111, Algeria.
authors.forename: Mohamed Al Amine
authors.initials: MA
authors.lastname: Benhacine
authors.affiliation: Laboratoire de Cristallographie-Thermodynamique, Faculté de Chimie, USTHB, BP 32 BEZ El Alia, Algiers 16111, Algeria.
authors.forename: Malika
authors.initials: M
authors.lastname: Hamadène
authors.affiliation: Unité de Recherche de Chimie de l'Environnement et Moléculaire Structurale (CHEMS), Faculté des Sciences Exactes, Université des frères Mentouri, Constantine 1, 25000, Algeria.
authors.forename: Sofiane
authors.initials: S
authors.lastname: Bouacida
authors.affiliation: Unité de Recherche de Chimie de l'Environnement et Moléculaire Structurale (CHEMS), Faculté des Sciences Exactes, Université des frères Mentouri, Constantine 1, 25000, Algeria.
authors.forename: Hocine
authors.initials: H
authors.lastname: Merazig
keywords: IR; UV–visible; absolute structure; chains; crystal structure; iron(III); one-dimensional coordination polymer; oxalate; precursor; sodium(I)