A new chiral rare-earth organic framework constructed by tartaric acid: synthesis, structural, thermal investigations and optical properties.

Hydrothermal reactions of rare-earth cerium with L-tartaric acid afford a new coordination polymer, namely, poly[[triaqua(µ4-L-tartrato)cerium(III)] chloride], {[Ce(C4H4O6)(H2O)3]Cl}n, (1). The structure was determined by single-crystal X-ray diffraction analysis and further characterized by IR and UV-Vis spectroscopy, powder X-ray diffraction and thermogravimetric analysis. Single-crystal X-ray diffraction analysis revealed that the compound is a new two-dimensional (2D) double-layered structure with one-dimensional left-handed helical chains. The different intermolecular interactions were confirmed using Hirshfeld surface analysis and molecular fingerprint plots. Molecular 2D fingerprint plots quantify the different interactions and highlight that H...H (24.8%), H...O/O...H (26.3%), Cl...H/H...Cl (19.6%), O...O (13.8%) and Ce...O/O...Ce (13.6%) interactions account for 99.8% of all contacts. Additionally, the photoluminescence properties of the compound were investigated in the solid state.

Alkali and alkaline earth coordination polymers constructed from benzene-1,2,4,5-tetracarboxylic acid and flexible dicarboxylate acid ligands: syntheses, structures and spectroscopic and thermal properties.

Two new metal coordination complexes, namely, poly[aqua(µ6-benzene-1,2,4,5-tetracarboxylic acid-κ8O1:O1,O2:O2':O4:O4,O5:O5')(µ-but-2-enedioato-κ2O1:O4)potassium(I)], [K2(C4H2O4)(C10H6O8)(H2O)2]n or [K2(fum)(H4btec)(H2O)2]n, (1), and poly[aqua(µ8-2,5-dicarboxybenzene-1,4-dicarboxylato-κ12O1:O1',O2:O2,O2':O2':O4:O4',O5:O5,O5':O5')(µ-ethanedioato-κ4O1,O2:O1',O2')strontium(II)], [Sr2(C2O4)(C10H4O8)(H2O)2]n or [Sr2(ox)(H2btec)(H2O)2]n, (2) (H4btec = benzene-1,2,4,5-tetracarboxylic acid, H2btec = 2,5-dicarboxybenzene-1,4-dicarboxylate, fum = fumarate and ox = oxalate), have been obtained under hydrothermal conditions by reacting the different alkali and alkaline earth metal salts with H4btec, fumaric acid (H2fum) and oxalic acid (H2ox). Complexes (1) and (2) were structurally characterized by single-crystal X-ray diffraction, IR and UV-Vis spectroscopy, powder X-ray diffraction (PXRD) and thermogravimetic analysis-differential scanning calorimetry (TGA-DSC). Complex (1) displays a two-dimensional (2D) layer with the K+ ion in a distorted pentagonal bipyramidal geometry and exhibits a uninodal 6-connected hxl/Shubnikov plane net (3,6) with {36.46.53} topology. Complex (2) displays a three-dimensional (3D) network structure, in which the Sr2+ ion is in a distorted monocapped square antiprism geometry. The framework possess a binodal (5,8)-connected net with the Schläfli symbol {32.410.58.64.74}{32.46.52}2. The 3D Hirshfeld surfaces and 2D fingerprint plots show that the main interactions are the O...H/H...O intermolecular interactions. Moreover, the thermal decompositions of (1) and (2) in the temperature range 303-1273 K revealed that they both decompose in three steps and transform to the corresponding metal oxide.

Synthesis, crystal structure, and thermal properties of poly[aqua-(µ5-2,5-di-carb-oxy-benzene-1,4-di-carboxyl-ato)strontium].

A coordination polymer formulated as [Sr(H2BTEC)(H2O)] n (H4BTEC = benzene-1,2,4,5-tetra-carb-oxy-lic acid, C10H6O8), was synthesized hydro-thermally and characterized by single-crystal and powder X-ray diffraction, scanning electron microscopy and thermal analysis. Its crystal structure is made up of a zigzag inorganic chain formed by edge-sharing of [SrO8] polyhedra running along [001]. Adjacent chains are connected to each other via the carboxyl-ate groups of the ligand, resulting in a double-layered network extending parallel to (100). O-H⋯O hydrogen bonds of medium-to-weak strength between the layers consolidate the three-dimensional structure. One of the carb-oxy-lic OH functions was found to be disordered over two sets of sites with half-occupancy.

Two novel alkaline earth coordination polymers constructed from cinnamic acid and 1,10-phenanthroline: synthesis and structural and thermal properties.

In coordination chemistry and crystal engineering, many factors influence the construction of coordination polymers and the final frameworks depend greatly on the organic ligands used. The diverse coordination modes of N-donor ligands have been employed to assemble metal-organic frameworks. Carboxylic acid ligands can deprotonate completely or partially when bonding to metal ions and can also act as donors or acceptors of hydrogen bonds; they are thus good candidates for the construction of supramolecular architectures. We synthesized under reflux or hydrothermal conditions two new alkaline earth(II) complexes, namely poly[(1,10-phenanthroline-κ2N,N')bis(µ-3-phenylprop-2-enoato-κ3O,O':O)calcium(II)], [Ca(C10H7O2)2(C10H8N2)]n, (1), and poly[(1,10-phenanthroline-κ2N,N')(µ3-3-phenylprop-2-enoato-κ4O:O,O':O')(µ-3-phenylprop-2-enoato-κ3O,O':O)barium(II)], [Ba(C10H7O2)2(C10H8N2)]n, (2), and characterized them by FT-IR and UV-Vis spectroscopies, thermogravimetric analysis (TGA) and single-crystal X-ray diffraction analysis, as well as by powder X-ray diffraction (PXRD) analysis. Complex (1) features a chain topology of type 2,4 C4, where the Ca atoms are connected by O and N atoms, forming a distorted bicapped trigonal prismatic geometry. Complex (2) displays chains of topology type 2,3,5 C4, where the Ba atom is nine-coordinated by seven O atoms of bridging/chelating carboxylate groups from two cinnamate ligands and by two N atoms from one phenanthroline ligand, forming a distorted tricapped prismatic arrangement. Weak C-H...O hydrogen bonds and π-π stacking interactions between phenanthroline ligands are responsible to the formation of a supramolecular three-dimensional network. The thermal decompositions of (1) and (2) in the temperature range 297-1173 K revealed that they both decompose in three steps and transform to the corresponding metal oxide.

A novel three-dimensional SrII coordination polymer based on benzene-1,2,4,5-tetracarboxylate: hydrothermal synthesis, crystal structure and spectroscopic and thermal studies.

Coordination of the anions of benzenecarboxylic acids with metal cations leads to coordination polymers with various structural features. Very few examples of strontium-based structures have been reported. A new three-dimensional coordination polymer, namely poly[aqua(µ12-benzene-1,2,4,5-tetracarboxylato)distrontium(II)], [Sr2(C10H2O8)(H2O)]n, has been synthesized under hydrothermal conditions and characterized by thermal analysis, vibrational spectroscopy (Raman and IR), single-crystal X-ray diffraction and powder X-ray diffraction. The coordination geometries around the two independent SrII ions can be described as a distorted dodecahedron and a distorted monocapped square antiprism. The compound features a three-dimensional structure containing inorganic motifs, with two-dimensional layers connected through organic linkers, and possesses a topologic structure of a binodal (6,12) connected alb net with the Schläfli symbol {415}2{448.618}. The final product of thermal decomposition is strontium oxide (SrO).

Hydro-thermal synthesis and crystal structure of a new lanthanum(III) coordination polymer with fumaric acid.

The title compound, poly[di-aqua-tris-(µ4-but-2-enedioato)(µ2-but-2-enedioic acid)dilanthanum(III)], [La2(C4H2O4)3(C4H4O4)(H2O)2] n , was synthesized by the reaction of lanthanum chloride penta-hydrate with fumaric acid under hydro-thermal conditions. The asymmetric unit comprises an La(III) cation, one and a half fumarate dianions (L (2-)), one a half-mol-ecule of fumaric acid (H2 L) and one coordinated water mol-ecule. Each La(III) cation has the same nine-coordinate environment and is surrounded by eight O atoms from seven distinct fumarate moieties, including one proton-ated fumarate unit and one water mol-ecule in a distorted tricapped trigonal-prismatic environment. The LaO8(H2O) polyhedra centres are edge-shared through three carboxyl-ate bridges of the fumarate ligand, forming chains in three dimensions to construct the MOF. The crystal structure is stabilized by O-H⋯O hydrogen-bond inter-actions between the coordin-ated water mol-ecule and the carboxyl-ate O atoms, and also between oxygen atoms of fumaric acid.

Poly[[penta-aqua-bis-(µ3-hydrogen squarato)barium] monohydrate].

The crystal structure of the title compound, {[Ba(C4HO4)2(H2O)5]·H2O} n , consists of discrete double chains propagating along [010]. The chains are formed by Ba(II) ions linked by bridging hydrogen squarate ligands in a trans-bis-monodentate mode. In addition, the bridging hydrogen squarate ligands connect the chains into a ladder structure via a third coordinating O atom. The remaining coordination sites are occupied by five aqua ligands and a second mondendate hydrogen squarate ligand, forming a slightly distorted tricapped trigonal-prismatic geometry. O-H⋯O hydrogen bonds link the chains and solvent water mol-ecules into a three-dimensional network.

Poly[1H-imidazol-3-ium [di-µ-nitrato-sodium]].

In the title compound {(C3H5N2)[Na(NO3)2]} n , the Na(I) ion is coordinated by eight O atoms from three bidentate nitrate anions and two O atoms from two monodentate nitrate anions, displaying a bicapped trigonal-prismatic geometry. The imidazolium cation is essentially planar (r.m.s. deviation for all non-H atoms = 0.0018 Å). In the crystal, the Na(I) ions are connected by bridging nitrate ligands, forming layers parallel to (010). The imidazolium cations are sandwiched between these layers. Weak C-H⋯O hydrogen bonds link the layers into a three-dimensional network. In addtion, π-π inter-actions between the imidazolium rings [centroid-centroid distance = 3.588 (3) Å] are observed.

Poly[[µ-aqua-tetraaquabis(µ-2-hydroxy-4-oxocyclobut-1-ene-1,3-diolato)strontium] hemihydrate].

In the title coordination polymer, {[Sr(C(4)HO(4))(2)(H(2)O)(5)]·0.5H(2)O}(n), the Sr(2+) ion is coordinated by three monodentate hydrogensquarate (hsq) anions and six aqua ligands in a distorted SrO(9) monocapped square-anti-prismatic geometry. The hsq anions and water mol-ecules bridge the metal ions into infinite sheets lying parallel to (100). The O atom of the uncoordinated water mol-ecule lies on a crystallographic twofold axis. The packing is stabilized by numerous O-H⋯O hydrogen bonds.

catena-Poly[[{bis-[tetra-aqua-(2-hy-droxy-3,4-dioxocyclo-but-1-en-1-olato-κO)bariumstrontium(0.35/0.65)]di-µ-aqua}-bis-(µ-2-hy-droxy-4-oxocyclo-but-1-ene-1,3-diolato-κO:O)] monohydrate].

The title structure, {[Ba(0.71)Sr(1.29)(C(4)HO(4))(4)(H(2)O)(10)]·H(2)O}(n), is built from dimers of edge-sharing monocapped square anti-prisms [(Ba/Sr)O(3)(H(2)O)(6)], in which barium and strontium are statistically disordered [ratio 0.353 (8):0.647 (8)] on the same crystallographic site. Such dimers are connected via bidentate hydrogen squarate groups [HC(4)O(4)](-), leading to chains that propagate along the b axis. Inter- and intra-molecular O-H⋯O hydrogen bonds maintain the crystal packing through a three-dimensional network.