Btec Ligands Research Articles

Photoluminescence properties of Gd(III) and Ce(III) lanthanide based metal organic frameworks

The Gd(III) and Ce(III) based-MOFs (metal organic frameworks) have been synthesized by hydrothermal method using 1,2,4,5­benzenetetracarboxylate (btec) ligand and characterized by elemental analysis, FT-IR, UV-visible and single-crystal X-ray diffraction. The crystal structure analysis of Gd(III) complex [C 10 H 9 GdO 11 ] ( 1 ) and Ce (III) complex [C 10 H 5 CeO 9 ] ( 2 ) show that the central lanthanide ions are coordinated by nine oxygen atoms in which eight O atoms from btec ligands and one O atom from water molecule for both structures. The nearest non-bonding Gd···Gd distance is 3.928 A while Ce···Ce distance is 4.392 A. Complex 1 and 2 bridged by oxygen atoms of btec ligands are formed in 3D networks via strong hydrogen bonds. Additionally, solid state photoluminescence properties of 1 and 2 at room temperature have been investigated. Under the excitation of UV light, intense cyan-blue emission for complex 1 and blue emission for complex 2 are exhibited in the visible regions.

Construction of diverse CdII/ZnII coordination polymers based on 5-(quinolyl)tetrazolate generated via in situ hydrothermal synthesis

By variation of reaction parameters such as metal salts and secondary ligands, a series of new coordination polymers, [Cd(QTZ)2] (1), [Cd(QTZ)N3·H2O] (2), [Zn(QTZ)Cl] (3), [Cd2(QTZ)2(INA)2]·0.25H2O (4), [Cd2(QTZ)(btrc)·2(H2O)]·1.67H2O (5), 2[Cd3(QTZ)2(btec)·H2O]·H2O (6) (QTZ = 5-(quinolyl)tetrazole; HINA = isonicotinic acid; H3btrc = 1,3,5-benzenetricarboxylic acid; H4btec = 1,2,4,5-benzenetetracarboxylic acid) were successfully synthesized under hydrothermal reactions and structurally characterized by single-crystal X-ray diffraction. The QTZ ligands in these compounds are in situ generated from a [2 + 3] cycloaddition reaction of 3-quinolinecarbonitrile and NaN3 in water with the acid of CdII/ZnII salt. Compound 1 displays a three-dimensional (3D) 2-fold interpenetrating diamond network with Schläfli symbol 66. Compound 2 represents a two-dimensional (2D) coordination framework constructed of infinite Cd–N3− chains and QTZ ligands. Compound 3 exhibits a 4-connected 2D (4,4) net built up by interconnection of Zn2(QTZ)2Cl2 subunits. Compound 4 is a 2D framework constructed by interconnection of Cd2(QTZ)2(INA)2 subunit and Cd2(QTZ)2 subunit. Compound 5 exhibits a 2D layered structure with the Cd2–QTZ chain extended by btrc ligands. In compound 6, trinuclear CdII clusters link each other by pairs of QTZ ligands to form an infinite zigzag Cd3–QTZ chain; furthermore the adjacent Cd3–QTZ chains are extended by the btec ligands to form a 3D network. These results indicate that QTZ is a powerful functional ligand and the nature of secondary ligands and transition metal ions also play significant roles in dominating molecular self-assembled structure. In addition, the luminescent properties of all compounds have been investigated in the solid state at room temperature.

Poly[[hexa-μ-aqua-diaquabis(μ4-dihydrogen benzene-1,2,4,5-tetracarboxylato)magnesiumdisodium] dihydrate

The asymmetric unit of the title compound, {[MgNa2(C10H4O8)2(H2O)8]·2H2O}n, contains one octa­hedrally coordin­ated MgII atom (site symmetry 2/m), one octahedrally coordinated NaI atom (site symmetry 2) and one half of the dihydrogen benzene-1,2,4,5-tetra­carboxyl­ate (btec) ligand, the second half of the ligand being generated by a twofold rotation axis. The basic framework of the title compound features infinite (–Na–Na–Mg–)n chains along [10-1] with the metal cations bridged by the coordinating water molecules. The chains are isolated from each other by μ4-bridging btec ligands, which form inter­molecular O—H⋯O hydrogen bonds to uncoordinated water mol­ecules and the coordinated water mol­ecules of a neighbouring chain. In each btec ligand, there are also intramolecular O—H⋯O hydrogen bonds.

Syntheses and structures of five 1D coordination polymers based on quinolone antibacterial agents and aromatic polycarboxylate ligands

A series of one-dimensional (1D) metal–quinolone coordination polymers, namely [Zn(levofH)(sdba)]·H2O (1), [M(cfH)(oba)(H2O)2] (M=Co (2) and Ni (3)), [Cu4(ppaH)2(btec)2(H2O)4]·3H2O (4) and [Cu4(norfH)2(btec)2(H2O)4]·3H2O (5) (levofH=levofloxacin, cfH=ciprofloxacin, ppaH=pipemidic acid, norfH=norfloxacin, sdba=4,4′-sulfonyldibenzoate, oba=4,4′-oxybis(benzoate), btec=1,2,4,5-benzenetetracarboxylate) have been hydrothermally synthesized and characterized by elemental analyses, IR spectra and TG analyses. Compound 1 is a unique 1D chiral metal–levofH complex. Compounds 2 and 3 are isostructural and contain similar chains constructed from [M(cfH)2(H2O)2] fragments linked by oba ligands. The structures of compounds 4 and 5 are analogous and both feature ladders constructed from CuII ions linked by btec ligands. In addition, the magnetic property of compound 4 has been studied, which exhibits an antiferromagnetic interaction.

Poly[μ-aqua-aqua(μ-benzene-1,2,4,5-tetracarboxylato)gadolinate(III)potassium(I)

In the title compound, [KGd(C10H2O8)(H2O)2]n, the Gd3+ ion is nine-coordinated by eight O atoms from five individual benzene-1,2,4,5-tetra­carboxyl­ate (btec) ligands and one water mol­ecule, and the K+ ion is eight-coordinated by six O atoms from five individual btec ligands and two water mol­ecules. In the crystal, the btec half-mol­ecules are completed by crystallographic inversion symmetry. GdO9 and KO8 polyhedra are connected, forming layers in the ab plane, which are further inter­connected by μ8- or μ12-bridging btec ligands, forming a three-dimensional structure.

Two New 2D Metal‐Organic Framework Structures Based on Different Polycarboxylate Anions and Analogue (Pyridyl)imidazole Derivative

AbstractTwo new CdII coordination frameworks with the semirigid asymmetric ligand L, [Cd2L2(p‐bdc)]n (1) and [CdL(btec)0.25]n (2) (L = 4‐[(2‐(pyridine‐2‐yl)‐1H‐imidazol‐1‐yl)methyl]benzoic acid, p‐bdc = 1,4‐benzenedicarboxylic acid, btec = 1,2,4,5‐benzenetetracarboxylic acid), were synthesized hydrothermally. In complex 1, p‐bdc ligands link [Cd2(COO)4N4] double‐chains to give a 2D network. In complex 2, two CdII ions and two ligands L form a 26‐membered ring, which is further connected by btec ligands in chelate‐monodentate coordination modes to construct a 2D polymeric sheet. In addition, the photoluminescence properties of the free ligand L and the two complexes were studied in the solid state at room temperature

Self-assembly of Two Cobalt(II) Coordination Polymers with 1,2,4,5-benzenetetracarboxylate and 1,3-bi(4-pyridyl)propane Ligands

Two cobalt(II) coordination polymers [Co(H2O)2(H2btec) (bpp)2] n (1) and {[Co2(H2O)4(bpp)3(btec)]· 4H2O} n (2) were synthesized under ambient conditions with 1,2,4,5-benzenetetracarboxylic acid (btec) and 1,3-bi(4-pyridyl)propane (bpp) as mixed ligands. Complex 1 is characteristic of one-dimensional chains bridged by H2btec ligands, the terminal bpp ligands complete the coordination sphere of the cobalt atoms and are further hydrogen-bonded to neighboring chains via O–H· · · N bonds. Complex 2 features a three-dimensional framework constructed by btec4– and co-bridging bpp ligands. The cobalt ions in 2 are joined together by the btec ligands to generate Co4 squares which link to each other in an corner-sharing mode to form a 3D topology. The terminal bpp ligands filling in the networks further contribute to the stability of the crystal structure.

Alkali Metal Cation (K+, Cs+) Induced Dissolution/Reorganization of Porous Metal Carboxylate Coordination Networks in Water

Porous metal-organic coordination networks (MOCNs) {A(2)[M(3)(btec)(2)(H(2)O)(4)]}(n) (1, A=K, M=Co; 2, A=K, M=Ni; 3, A=Cs, M=Co; and 4, A=Cs, M=Ni; btec=benzene-1,2,4,5-tetracarboxylate) with nearly identical structural features were hydrothermally prepared. These compounds adopt (4,8)-connected scu nets but exhibit subtle differences in the topology of the final three-dimensional architectures. Compound 1 has a regular net with the largest solvent void (21.1 %), while the nets of the other three (2-4) are slightly distorted from a regular shape and have malformed pores with smaller solvent voids (5.4-11.4 %). Likely, the different supramolecular environments among 1-4 subtly depend on the eight-connected binodal cubical vertices/four-connected square-planar connectivity between the trimetallic clusters and the btec ligands. Cobalt species 3 dissolved in an aqueous solution of KCl, and then reorganized to form 1 at ambient temperature. Interestingly, under similar conditions, 1 dissolved and then was regenerated to give the same structure. Nickel species 2 and 4 also underwent a dissolution/reorganization process in an aqueous solution of KCl to afford new metal-carboxylate product {K(2)[Ni(3)(btec)(2)(H(2)O)(4)]}(n) (2'). This compound forms a (4,8)-connected scu net with regular pores, which is isostructural and isomorphous with 1, and is a supramolecular isomer of 2. Similarly, in an aqueous solution of CsCl, 1-4 were converted to 1D zigzag chain structures {Cs(2)[M(btec)(H(2)O)(4)]}(n) (5, M=Co; 6, M=Ni) that enlarged to hydrogen-bonded 3D porous supramolecular networks. Remarkable, reversible alkali metal cation induced structural transformations between 1 and 5 occurred via dissolution/reorganization processes. Thermogravimetric analyses showed that these metal-carboxylate species have high thermal stability (T>300 degrees C).

Synthesis and Crystal Structure of a Novel Double-Chain Coordination Polymer [Zn2(bipy)2(btec)(H2O)2]n (bipy = 2,2′-bipyridine; btec = 1,2,4,5-benzenetetracarboxylate)

A novel aromatic polycarboxylate polymer, [Zn2(bipy)2(btec)(H2O)2]n (1), has been synthesized and structurally characterized by the single crystal X-ray diffraction. Compound 1 belongs to the triclinic crystal system, space group P-1; a = 7.7449(6) A, b = 8.9286(8) A, c = 10.7422(8) A, α = 80.95(1)°, β = 70.21(1)°, γ = 78.14(1)°, V = 680.93(10) A3, Z = 2. The coordination geometry of Zn(II) atom is distorted trigonal bipyramidal with two nitrogen atoms of one 2,2′-bipy group, two oxygen atoms from two different btec ligands, and one water. The 16-membered rings are alternately arranged forming an infinite 1-D double-chain structure. A 3-D network was constructed by interlayer C···H–O, O···H–O hydrogen bonds and π–π stacking interactions. Compound 1 exhibits fluorescence at room temperature in the solid state. A 1-D double-chain aromatic polycarboxylate polymer, [Zn2(bipy)2(btec)(H2O)2]n (1), has been synthesized and structurally characterized by the single crystal X-ray diffraction. A 3-D network was constructed by intermolecular C···H–O, O···H–O hydrogen bonds and π–π stacking interactions. Compound 1 exhibits fluorescence at room temperature in the solid state.

Hydrothermal synthesis and crystal structure of an infinite 1D ladderlike metal-organic compound: [Cu 2(btec)(2,2′-bipy) 2] ∞ (btec=1,2,4,5-benzenetetracarboxylate)

A new metal-organic hybrid compound [Cu 2(btec)(2,2′-bipy) 2] ∞ (btec=1,2,4,5-benzenetetracarboxylate) has been hydrothermally synthesized and characterized by elemental analyses, IR spectrum, TG analysis and single-crystal X-ray diffraction. Dark-blue crystals crystallizes in the monoclinic system, space group P2(1)/ n, a=7.2587(15) Å, b=12.396(3) Å, c=14.428(3) Å, β=103.87(3)°, V=1260.4(4) A ̊ 3, Z=2, R1=0.0553, wR2=0.1746. The title compound exhibits a new infinite 1D ladderlike chain architecture constructed from the {Cu(2,2′-bipy)} 2+ moieties and btec ligands. Furthermore, the adjacent chains are stacked into a 3D supramolecular framework via π–π stacking interactions of bipy groups and intermolecular hydrogen bonding interactions.

Nickel(II) and manganese(II) 1D chain coordination polymers with 1,2,4,5-benzenetetracarboxylato anions

Five new coordination complexes were synthesized under ambient conditions in water, or water/ethanol by combining a Mn 2+ or Ni 2+ salt with BTEC and an imidazole derivative forming [Mn(Him) 4(H 2O) 2][Mn(BTEC)(Him) 2(H 2O) 2]·4H 2O ( 1), [Ni(Him) 4(H 2O) 2][Ni(BTEC)(Him) 2(H 2O) 2]·4H 2O ( 2), [2-MeH 2im] 2[Mn(BTEC)(H 2O) 4]·5H 2O ( 3), [Mn(4-MeHim) 6][Mn(BTEC)(H 2O) 4]·H 2O ( 4), and [Mn 2(BTEC)(HBzim) 4(H 2O) 6]·2H 2O ( 5) (BTEC=1,2,4,5-benzenetetracarboxylate; Him=imidazole; 2-MeH 2im=2-methylimidazolium; 4-MeHim=4-methylimidazole; HBzim=benzimidazole). Complexes 1– 5 were characterized by TGA, FT-IR, elemental analysis and X-ray crystallography. Complexes 1– 5 all crystallize in the triclinic space group P1̄. Complexes 1– 4 are coordination polymers, possessing 1D linear chain structures, while complex 5 is a discrete bimetallic complex. The anionic linear 1D chains in 1– 4 are comprised of BTEC ligands that bridge between metal atoms. The cations are either metal complexes ( 1, 2 and 4) or protonated 2-MeHim ( 3), which has a lower p K b.

New two-dimensional metal-organic networks constructed from 1,2,4,5-benzenetetracarboxylate and chelate ligands.

Two novel nickel coordination polymers [Ni(2)(2,2'-bipy)(2)(OH)(2)(H(2)btec)](3)(n)(1) and [Ni(2)(1,10'-phen)(2)(H(2)O)(2)(btec)](n)(2) (btec = 1,2,4,5-benzenetetracarboxylate) have been hydrothermally synthesized and characterized by elemental analyses, IR and XPS spectra, TG analysis, X-ray powder diffraction, and single crystal X-ray diffraction. Crystal data for 1: C(90)H(66)N(12)O(30)Ni(6), monoclinic P2(1)/c, a = 10.905(2) A, b = 18.006(4) A, c = 20.551(4) A, beta = 94.91(3) degrees, Z = 2. Crystal data for 2: C(34)H(22)N(4)O(10)Ni(2), monoclinic P2(1)/n, a = 10.122(2) A, b = 9.3106(19) A, c = 15.690(3) A, beta = 92.03(3) degrees, Z = 2. Compound 1 exhibits a novel one-dimensional chainlike structure, in which the dinuclear Ni centers are linked by the btec ligands. Furthermore, the adjacent chains are linked into a 2-D wavelike layer via the strong OH.O hydrogen bonding interactions. Compound 2 possesses an unusual two-dimensional steplike network with interesting rhombic grids. Both compounds exhibit unprecedented metal-organic ligand construction modes in [M/btec/L] (M = transition metal; L = chelate ligands) systems. The magnetic behaviors of compounds 1 and 2 have been studied.

Copper(ii) and cobalt(ii) coordination polymers with bridging 1,2,4,5-benzenetetracarboxylate and N-methylimidazole: coordination number-determined sheet topology

Two new coordination polymers were synthesized under ambient conditions in water by combining a cobalt(II) or copper(II) metal salt with 1,2,4,5-benzenetetracarboxylate (BTEC) and N-methylimidazole (Meim), forming Co2(BTEC)(Meim)4(H2O)4·H2O (1) and Cu2(BTEC)(Meim)4 (2). Compounds 1 and 2 were characterized by X-ray crystallography, powder X-ray diffraction, TGA, FT-IR and elemental analysis. The crystal structures and 2D polymeric structures of compounds 1 and 2 are reported. Coordination polymer 1 crystallizes in the monoclinic space group C2/c. Coordination polymer 2 crystallizes in the triclinic space group P. Both 1 and 2 are made up of infinite sheets of BTEC ligands and metal ions. The sheets in 1 are puckered, giving an offset zigzag sheet topology, while the sheets in 2 are flat. Significant π–π stacking between Meim rings on adjacent sheets contributes to inter-sheet interactions in both 1 and 2. While hydrogen bonding does not play a role in 2, significant hydrogen bonding between sheets in 1 also stabilizes inter-sheet interactions.