Bdc Anions Research Articles

From discrete molecules to one-dimensional coordination polymers containing Mn(II), Zn(II) or Cd(II) pyridine-2-aldoxime building unit

The syntheses, spectroscopic characterization and crystal structures for eight coordination compounds [Cd(HCO2)2(pya)2] (1), {[M(bdc)(pya)].1.5DMF}n (M=Mn(II), Zn(II), Cd(II) (2–4), [Zn(SO4)(pya)(H2O)3](H2O) (5), [(ZnSO4)2(pya)4] DMF.2H2O (6), [Zn(SO4)(pya)(H2O)2]n (7), and [Cd(SO4)(pya)(H2O)]n (8) [pya=pyridine-2-aldoxime, bdc=1,4-benzenedicarboxylate, DMF=N,N′-dimethylformamide] are reported. Compounds 1–4 and 6 contain two, while 5, 7, and 8 contain one neutral pya ligand coordinated in a chelate mode to the metal center through the Npyridyl and Noxime atoms. The dicarboxylic bdc anions provide an access to 1D polymeric arrays in 2–4. The hybrid sulfates including discrete mononuclear (5), binuclear (6), and 1D polymeric (7, 8) coordination arrays were obtained due to different binding modes of coordinated sulfate anion. While solid state fluorescence of new polymeric compounds 2–4 is similar to that of the H2bdc ligand, a rare dual emission is observed for compounds 7 and 8. According to TD-DFT calculations, emission at 400 and 650nm originates from nπ∗ and ππ∗ states of the pya ligand respectively.

Assembly of Zn/Cd coordination polymers containing helixes or polycatenane structures tuned by the tri-pyridyl–bis-amide ligands with different spacer: syntheses, structures, photoluminescent and photocatalytic properties

Four new d10 metal–organic coordination polymers tuned by the “V”-shaped tri-pyridyl–bis-amide ligands with different spacers, namely, [Zn(L1)(BDC)]·H2O (1), [Cd(L1)(BDC)]·H2O (2), [Zn(L2)(BDC)] (3) and [Cd(L2)(BDC)] (4) (L1 = N,N′-bis(pyridine-3-yl)pyridine-2,6-dicarboxamide, L2 = N,N′-bis(pyridine-3-yl)pyridine-3,5-dicarboxamide, H2BDC = 1,4-benzenedicarboxylic acid) have been synthesized under hydrothermal conditions. In complexes 1 and 2, the metal ions are linked by L1 to form left- and right-helical Zn/Cd–L1 chains, which are further extended into two-dimensional (2D) wave-like layers by BDC anions. In 3, two L2 ligands link two ZnII ions forming the Zn2(L2)2 loops, which are connected by BDC anions to form a (2·65) topological 2D network. In addition, the large Zn2(L2)2 loops are threaded by the BDC rods from above and below 2D layers so as to form 2D → 3D polyrotaxane and polycatenane structures. In 4, the CdII ions are linked by L2 ligands to generate 1D double chain ribbons with Cd2(L2)2 loops, which are further connected by the BDC linkers to form a 3D framework. Two identical 3D frameworks interpenetrate each other in a twofold mode, giving rise to a polyrotaxane and polycatenane array, which is relative limited. The diverse structures of complexes 1–4 demonstrate that the tri-pyridyl–bis-amide ligands and the central metals have significant effect on the final structures. The thermal stability and fluorescent properties of complexes 1–4 have been investigated. In addition, the title complexes exhibit photocatalytic activity for dye methylene blue degradation under UV light.

Poly[[aquatris(μ-benzene-1,4-dicarboxylato)tricobalt(II)] methanol monosolvate monohydrate

The asymmetric unit of the title compound, {[Co3(C8H4O4)3(H2O)]·CH3OH·H2O}n, consists of four crystallographically independent Co cations, four benzene-1,4-dicarboxyl­ate (bdc) anions, two water and one methanol solvent mol­ecule. Two of the Co cations and two of the bdc anions are located on centres of inversion, whereas all other atoms are located in general positions. In the crystal, two Co atoms are only fourfold coordinated by three O atoms from three bdc ligands and by one O atom from one coordinated water mol­ecule, while a third Co atom is coordinated by four O atoms from four bdc ligands within a strongly distorted tetra­hedral geometry. The other two Co cations are octa­hedrally coordinated by six O atoms from six bdc anions. The Co cations are linked by the bdc anions into a three-dimensional framework. From this arrangement, cavities are formed in which additional methanol and water mol­ecules are embedded.

Syntheses, structures, photoluminescence and magnetic properties of four new metal–organic frameworks based on imidazoleligands and aromatic polycarboxylate acids

Four metal–organic coordination polymers, {[Cu2(4,4′-bibp)2(NO2)3)]·(NO2)(H2O)}n (1), [Cd(bdc)(4,4′-bibp)]n (2), {[Co2(bdc)2(4,4′-bibp)3(H2O)2]·(H2O)2}n (3), [Zn(Hbtc)(1,4-bix)]n (4) (4,4′-bibp = 4,4′-bis(1-imidazolyl)biphenyl; 1,4-bix = 1,4-bis((1H-imidazol-1-yl)methyl)benzene; H2bdc = 1,4-benzenedicarboxylate; H3btc = 1,3,5-benzenetricarboxylate) were obtained under hydrothermal conditions and characterized structurally. X-Ray diffraction analysis reveals that the four complexes exhibit new frameworks due to diverse coordination conformations. In copper compound 1, with mixed-valence copper(II)–copper(I), rigid linear 4,4′-bibp ligands connect two adjacent layers and the whole structure is a three-dimensional 6,6-connected network. In cadmium compound 2, 4,4′-bibp and bdc anions as bidentate ligands coordinate to cadmium cations to form a three-dimensional 4,4-connected network with a 3-fold interpenetrating framework. In cobalt compound 3, 4,4′-bibp and bdc anions also act as bidentate ligands, and coordinate to cobalt cations to form a three-dimensional 4,6-connected network. Zinc compound 4 shows that both the 1,4-bix ligand and btc anions act as bidentate bridging ligands, and connect the zinc cations to give a 2D polycatenated array structure. The magnetic properties for copper compound 1 and luminescent properties for cadmium compound 2 and zinc compound 4 are also discussed in detail.

Poly[tetraaquabis(μ3-benzene-1,3-dicarboxylato-κ3O:O′:O′′)bis(μ2-benzene-1,3-dicarboxylato-κ3O,O′:O′′)[μ2-1,4-bis(1,2,4-triazol-1-yl)butane-κ2N:N′]tetrazinc(II)

In the crystal structure of the title compound, [Zn4(C8H4O4)4(C8H12N6)(H2O)4]n, one ZnII atom is four-coordinated in a slightly distorted tetra­hedral geometry by two O atoms from benzene-1,3-dicarboxyl­ate (BDC) ligands, one N atom from a 1,4-bis­(1,2,4-triazol-1-yl)butane (BTB) ligand and one water mol­ecule, while a second ZnII atom is five-coordinated in a distorted square-pyramidal geometry bridged by four O atoms from BDC ligands and one water mol­ecule. The ZnII atoms are connected by the benzene-1,3-dicarboxyl­ate anions and the nitro­gen ligand into layers parallel to the ac plane. The asymmetric unit consits of two crystallographically independent ZnII cations, two BDC anions and two water mol­ecules in general positions, as well as one-half of the BTB ligand that is completed by inversion symmetry.

A novel silver(I)-containing supramolecular framework incorporating eight different hydrogen bond motifs

The reaction of AgNO 3, bipy and dicarboxylate gave rise to a novel supramolecular framework under ultrasonic irradiation at ambient temperature, namely [Ag 4(bipy) 4(bdc) 2·12H 2O] n (1) (bipy = 4,4-bipyridine, H 2bdc = 1,3-benzenedicarboxylate acid). Complex 1 is a three-dimensional (3D) supramolecular framework extended from the Ag-bipy chains by combination of coordination bonds and noncovalent interactions. In 1, the Ag-bipy chains are firstly extended into a two-dimensional (2D) cationic layer via Ag···Ag and π···π interactions between adjacent bipy ligands. The bdc anions and water molecules interact with each other into an anionic layer incorporating one-dimensional (1D) hydrogen-bonded distorted tubes along the c axis which are built by eight different edge-sharing hydrogen bonding motifs. The cationic and anionic layers are connected by abundant C–H···π interactions and inter-layer O–H···O and C–H···O hydrogen bonds to form the resulting 3D framework. Additionally, the thermal and photoluminescent properties of 1 were also discussed in details.

Syntheses, structures, photoluminescences of silver(I) coordination polymers with 2-aminopyrazine and varied dicarboxylate ligands

Four new silver(I) coordination polymers, namely [Ag(NH 2pyz)(ox) 0.5] n ( 1), [Ag(NH 2pyz)(adp) 0.5·2H 2O] n ( 2), [Ag 2(NH 2pyz) 2(bdc)·H 2O] n ( 3) and [Ag 2(NH 2pyz) 2.5(ndc)] n ( 4) [NH 2pyz = 2-aminopyrazine, ox = oxalate anion, adp = adipate anion, bdc = 1,4-benzenedicarboxylate anion, ndc = 1,4-naphthalenedicarboxylate anion] have been synthesized by solution phase ultrasonic reactions of Ag 2O with heterocyclic NH 2pyz and various dicarboxylates under ammoniacal conditions. The complexes were characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. Complex 1 is a three-dimensional (3D) framework with an α-ThSi 2 topology. Complex 2 features a 2D 4 4 -sql net involving infinite 1D double Ag-NH 2pyz chains and flexible adp anion spacers. Complex 3 is a 3D framework in which 1D single Ag-NH 2pyz chains are pillared by bdc anions to form a 2D 6 3 -hcb network, adjacent 2D networks are packed into a 3D framework through bridging O atoms of dbc anions. Complex 4 is a 2D structure built from infinite 1D stair-like chains containing finite Ag 4(NH 2pyz) 5 subunits. The results show that the structural diversity of the complexes result from the nature of the dicarboxylate ligands. The photoluminescence properties of the complexes were also investigated in the solid state at room temperature.

Controlled synthesis, structures and properties of one-, two-, and three-dimensional lanthanide coordination polymers based on (8-quinolyloxy)acetate

Hydrothermal reactions of Ln(NO3)3 and (8-quinolyloxy)acetic acid (HQOA) with auxiliary ligands resulted in a series of new one-, two- and three-dimensional (1D, 2D and 3D) coordination polymers, namely, [Ln(QOA)2 (H2O)2]·NO3·H2O [Ln = Eu (1), Gd (2)], [Ln2(QOA)4(ox)(H2O)]·3H2O [Ln = Pr (3), Er (4)], [Ln2(QOA)4(BDC) (H2O)]·4H2O [Ln = Sm (5)] and [Ln(QOA)(BDC)] [Ln = Sm (6), Eu (7)] [QOA = (8–quinolyloxy)acetate; ox = oxalate; BDC = 1, 4–benzenedicarboxylate], respectively. Compounds 1–2 possess 1D zigzag chains bridged by QOA anions and 3–4 contain 1D folded chains alternately bridged by oxalates and QOA anions. Complex 5 is an ordered (2,4)–connected 2D sheet-like structure. In compounds 6–7, four BDC anions bridge two adjacent metal atoms to form dinuclear lanthanide building blocks and these dinuclear blocks are further connected together to form an 8-connected 3D network. The progressive variation from 1D zigzag chains (1–2) to 1D folded chains (3–4) to a 2D layer network (5) and to 3D frameworks (6–7) is mainly attributed to the change of bridging ligands as well as the different coordination modes of organic carboxylic ligands. Moreover, the thermal stabilities and photoluminescent properties of these compounds show a remarkable difference due to the progressive variation of crystal structures.

A novel threefold-interpenetrating primitive cubic network based on a dinuclear Zn2node

In the mixed-ligand metal-organic polymeric compound poly[[mu(2)-1,4-bis(imidazol-1-yl)benzene](mu(2)-terephthalato)dizinc(II)], [Zn(2)(C(8)H(4)O(4))(2)(C(12)H(10)N(4))](n) or [Zn(2)(bdc)(2)(bib)](n) [H(2)bdc is terephthalic acid and bib is 1,4-bis(imidazol-1-yl)benzene], the asymmetric unit contains one Zn(II) ion, with two half bdc anions and one half bib molecule lying around inversion centers. The Zn(II) ion is in a slightly distorted tetrahedral environment, coordinated by three carboxylate O atoms from three different bdc anions and by one bib N atom. The crystal structure is constructed from the secondary building unit (SBU) [Zn(2)(CO(2))(2)N(2)O(2)], in which the two metal centers are held together by two bdc linkers with bis(syn,syn-bridging bidentate) bonding modes. The SBU is connected by bdc bridges to form a two-dimensional grid-like (4,4)-layer, which is further pillared by the bib ligand. Topologically, the dinuclear SBU can be considered to be a six-connected node, and the extended structure exhibits an elongated primitive approximately cubic framework. The three-dimensional framework possesses a large cavity with dimensions of approximately 10 x 13 x 17 A in cross-section. The potential porosity is filled with mutual interpenetration of two identical equivalent frameworks, generating a novel threefold interpenetrating network with an alpha-polonium topology [Abrahams, Hoskins, Robson & Slizys (2002). CrystEngComm, 4, 478-482].

Tossing and Turning: Guests in the Flexible Frameworks of Metal(III) Dicarboxylates

Single crystals of Ga(OH)(C(8)H(4)O(4)).0.74C(8)H(6)O(4) (2) and Ga(OH,F)(C(8)H(4)O(4)).0.74C(8)H(6)O(4) (3) were obtained under hydrothermal conditions. The structures of 2 and 3 have the same topological framework as the previously reported aluminum 1,4-benzenedicarboxylate (BDC), Al(OH)(C(8)H(4)O(4)).0.7C(8)H(6)O(4) (1). The frameworks are built by interconnecting M-OH-M chains (M = Al, Ga) with BDC anions to form large diamond-shaped one-dimensional channels filled with additional H(2)BDC guest molecules occupying disordered positions in the channels. Upon removal of H(2)BDC, other guest molecules such as H(2)O and pyridine can be inserted. In this work, we present a study of the intercalation of aromatic guests (BDC and pyridine) into frameworks of 1-3 by liquid and vapor diffusion into the empty channels of 1 and by single-crystal-to-single-crystal solvothermal guest exchange for 2 and 3. In the case of Al(OH)BDC and Ga(OH,F)BDC, two interconvertible, guest-concentration-dependent phases with different orientations of the pyridine guests have been observed, while only one pyridine orientation is found in Ga(OH)BDC.

Synthesis and Structures of Novel Lanthanide Benzenedicarboxylates

AbstractThree novel lanthanum benzenedicarboxylates La2(BDC)3(H2O)4 (1), La4(BDC)3(OH)6 (2) and La3(BDC)2(OH)5 (3) (BDC = 1,4-benzenedicarboxylate) were synthesized by hydrothermal reactions and their structures determined from single crystal X-ray diffraction. All three compounds are 3D framework structures consisting of layers of LaOn polyhedra cross-linked by BDC ligands along the layer stacking direction. In 1 the layers contain separated [LaO6(H2O)2] polyhedra that are bridged by the carboxylate groups of the BDC anions. Compounds 2 and 3 both have highly condensed lanthanum oxide-hydroxide polyhedra. In 2 the layers are wavy and consist of [LaO5(OH)4] and [LaO4(OH)5] polyhedra that share common corners, edges, and faces. In 3, the layers are similar but comprise [LaO3(OH)5] and [LaO4(OH)5] polyhedra.

Influence of Ligand Geometry on the Formation of In−O Chains in Metal-Oxide Organic Frameworks (MOOFs)

Three indium-oxide organic frameworks, In(2)O(1,3-BDC)(2), 1; In(OH)(2,6-NDC)(H(2)O), 2; and In(OH)(2,7-NDC)(H(2)O), 3 (BDC = benzene dicarboxylic acid and NDC = naphthalene dicarboxylic acid), were synthesized and characterized by thermogravimetric analysis, infrared spectroscopy, and single-crystal X-ray diffraction. Previously, we reported the structure of In(OH)(1,4-BDC).(0.75H(2)BDC), 0, where the framework is built by interconnecting In-OH-In chains with the BDC anions to form large diamond-shaped one-dimensional channels filled with guest molecules. Compounds 0-3 all contain In-O(H) chains, but the coordination and geometry depend on the nature of the dicarboxylate ligand. Compound 0 contains In-O octahedral centers that connect to form a single trans octahedral chain, while in compound 1, they connect to form a more complex double chain of octahedra. Both compounds 2 and 3 contain chains of connected pentagonal bipyramidal InO(6)(OH(2)) units. In 2, these units share trans vertices that are cross-linked by chelating 2,6-NDC anions, whereas in compound 3, cis vertices are shared to form chains that are linked by the 2,7-NDC anions.

A three-dimensional hydrogen-bonded coordination framework:catena-poly[[[tetraaquairon(II)]-μ-4,4′-bipyridine] benzene-1,4-dicarboxylate

The title compound, {[Fe(C10H8N2)(H2O)4](C8H4O4)}n or [Fe(bpy)(H2O)4](bdc) (bpy is 4,4′-bipyridine and bdc is benzene-1,4-dicarboxyl­ate), contains one-dimensional chains of FeII centres bridged by bpy ligands along the b axis, with the equatorial coordination of four water molecules completing the octahedral coordination. Non-coordinated bdc anions balance the charge of the FeII centres and bridge adjacent one-dimensional chains through an extensive hydrogen-bonding network. The compound crystallizes in the centrosymmetric space group P2/c, which defines twofold axes along both the Fe–bpy chains and the bdc anions.

Hydrothermal synthesis, structures and spectroscopy of 2D lanthanide coordination polymers built from helical chains: [Ln 2(BDC) 3(H 2O) 2] n (Ln=Sm, 1; Ln=Eu, 2; BDC=1,3-benzenedicarboxylate)

This article presents two lanthanide coordination polymers, [Ln 2(BDC) 3(H 2O) 2] n (Ln=Sm, 1; Ln=Eu, 2; BDC=1,3-benzenedicarboxylate) prepared by the hydrothermal technique, in the presence of 3,5-lutidine. The two complexes are characterized by IR spectra and X-ray diffraction. The luminescent spectroscopy of complex 2 has also been investigated. Crystal data: 1, C 24H 16O 14Sm 2, Monoclinic, P2 1/ n, a=13.362(4) Å, b=14.475(3) Å, c=13.568(2) Å, β=104.058(9)°, V=2545.7(10) Å 3, Z=4, μ=4.642 mm −1, D calc=2.163 g/cm 3, R 1=0.0237, wR 2=0.0587; 2, C 24H 16O 14Eu 2, Monoclinic, P2 1/ n, a=13.316(4) Å, b=14.437(3) Å, c=13.540(2) Å, β=103.956(9)°, V=2526.1(10) Å 3, Z=4, μ=4.994 mm −1, D calc=2.188 g/cm 3, R 1=0.0373, wR 2=0.1184. In these structures, Ln ions connecting with BDC anions are distributed in a helix-like 2D network, which is interlinked together by carboxylic groups.

Hydrothermal synthesis and structural studies of novel 2-D lanthanide coordination polymers with phthalic acid

This paper presents four lanthanide coordination polymers, [Ln2(BDC)3(H2O)]n (Ln = La, 1; Ln = Eu, 2; Ln = Tb, 3; BDC = 1,2-benzenedicarboxylate) and [Yb4(BDC)6(H2O)2]n (4) prepared by the hydrothermal technique. They are all 2-D infinite structures with BDC anions connecting adjacent metal ions. In complex 1, La(III) ions are eight- and nine-coordinated, and all La(III) ions are coplanar in the 2-D structure. In complexes 2 and 3, Eu(III) and Tb(III) ions are also eight- and nine-coordinated, but they are distributed in a wave-like 2-D network. In complex 4, the Yb(III) ions have four different coordination numbers (6, 7, 8 and 9), which are rarely found in one lanthanide complex. Both the coordination numbers and the arrangement of Ln atoms in these coordination polymers show the lanthanide contraction. In the four complexes, all the oxygen atoms of BDC take part in coordination with Ln(III) ions, adopting tetra-, penta- and hexadentate coordination modes for the phthalate anions. The luminescent properties of complex 2 have been investigated and the results for the explanation of the chemical environment of the Eu(III) ion are consistent with the X-ray analysis.