Improved bio-hydrogen production from glucose by adding a specific methane inhibitor to microbial electrolysis cells with a double anode arrangement.

Improved hydrogen production from glucose was achieved by adding a specific methane inhibitor (such as chloroform) to repress the activity of methanogens in a single-chamber microbial electrolysis cells (MECs) with a double anode arrangement. A maximum hydrogen production of 8.4±0.

Central-metal exchange, improved catalytic activity, photoluminescence properties of a new family of d(10) coordination polymers based on the 5,5'-(1H-2,3,5-triazole-1,4-diyl)diisophthalic acid ligand.

The rigid and planar tetracarboxylic acid 5,5'-(1H-2,3,5-triazole-1,4-diyl)diisophthalic acid (H4L), incorporating a triazole group, has been used with no or different pyridine-based linkers to construct a family of d(10) coordination polymers, namely, {[H2N(CH3)2]3[Cd3(L)2(HCOO)]}n (), {[Cd2(L)(py)6]·H2O}n (), {[H2N(CH3)2] [Cd2(L)(HCOO)(H2O)4]}n (), {[Zn(H2L)]·H2O}n (), and {[Zn(H2L)(4,4'-bipy)0.5]·C2H5OH·H2O}n () (py = pyridine, 4,4'-bipy = 4,4'-bipyridine). constructs a 3D porous network containing two kinds of channels: one is filled with coordinated HCOO(-) anions, and the other with [H2N(CH3)2](+) cations.

Surfactant-Assisted Nanocrystalline Zinc Coordination Polymers: Controlled Particle Sizes and Synergistic Effects in Catalysis.

Different morphologies and particle sizes of two crystalline zinc-based coordination polymers (CPs), [Zn(pytz)H2 O]n (1; H2 pytz=2,6-bis(tetrazole)pyridine) and [Zn2 (pytz)2 4 H2 O] (2), from the bulk scale to the nanoscale, could be obtained under solvothermal conditions with different surfactants (polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG) 2000) as templates. PVP and PEG 2000 could act as capping and structure-directing agents, respectively, to influence the growth of crystalline particles and control their sizes. CP 1 exhibits a two-dimensional framework with window-like units and 2 shows a bimetallic structure.

A Crystalline Copper(II) Coordination Polymer for the Efficient Visible-Light-Driven Generation of Hydrogen.

A crystalline coordination polymer (CP) photocatalyst (Cu-RSH) which combines redox-active copper centers with photoactive rhodamine-derived ligands remains stable in acid and basic solutions from pH 2 to 14, and efficiently catalyzes dihydrogen evolution at a maximum rate of 7.88 mmol g(-1)  h(-1) in the absence of a mediator and a co-catalyst. Cyclic voltammetry, control experiments, and DFT calculations established that copper nodes with open coordination sites and favorable redox potentials, aided by spatially ordered stacking of rhodamine-based linkers, account for the high catalytic performance of Cu-RSH.

Influence of ionic liquids on the syntheses and structures of Mn(II) coordination polymers based on multidentate N-heterocyclic aromatic ligands and bridging carboxylate ligands.

Seven Mn(ii) coordination polymers, namely {[Mn2(ptptp)Cl2(H2O)3]·H2O}n (1), {[Mn(μ-ptptp)3]2[Mn3(μ3-Cl)]2}·2Cl·16H2O (2), {[Mn2(ptptp)(ip)2(H2O)3]·H2O}n (3), {[Mn2(ptptp)(5-CH3-ip)2(H2O)3]·H2O}n (4), {[Mn4(ptptp)(5-Br-ip)3(H2O)3]·4H2O}n (5), {[Mn2(ptptp)(Hbtc)(H2O)2]·2H2O}n (6) and {[Mn2(ptptp)(tdc)(H2O)2]·1.5H2O}n (7), have been prepared based on multidentate N-heterocyclic aromatic ligands and bridging carboxylate ligands (H2ptptp = 2-(5-{6-[5-(pyrazin-2-yl)-1H-1,2,4-triazol-3-yl]pyridin-2-yl}-1H-1,2,4-triazol-3-yl)pyrazine; R-isophthalic acids, H2ip-R: R = -H (3), -CH3 (4), -Br (5); H3btc = trimesic acid (6); H2tdc = thiophene-2,5-dicarboxylic acid (7)), in order to further probe the multiple roles of [RMI]Br ionic liquids in the hydro/solvothermal synthesis (RMI = 1-alkyl-3-methylimidazolium, R = ethyl, or propyl, or butyl). The successful syntheses of complexes 2-6 suggest that in hydro/solvothermal synthesis the addition of a small amount of [RMI]Br plays a crucial role.

The effect of metal ions on photocatalytic performance based on an isostructural framework.

A series of 2D layered isostructural coordination complexes {[M3(L)2(H2O)6]·H2O}n (M = Mn (1), Mn0.7Co0.3 (2), Mn0.

Direct degradation of cellulosic biomass to bio-hydrogen from a newly isolated strain Clostridium sartagoforme FZ11.

A mesophilic hydrogen-producing strain, Clostridium sartagoforme FZ11, had been newly isolated from cow dung compost acclimated using microcrystalline cellulose (MCC) for at least 30 rounds in an anaerobic bioreactor, and identified by the 16S rDNA gene sequencing, which could directly utilized various carbon sources, especially cellulosic biomass, to produce hydrogen. The maximum hydrogen yields from MCC (10 g/l) and carboxymethyl cellulose (CMC, 10 g/l) were 77.2 and 64.

Reversible conversion of valence-tautomeric copper metal-organic frameworks dependent single-crystal-to-single-crystal oxidation/reduction: a redox-switchable catalyst for C-H bonds activation reaction.

Upon single-crystal-to-single-crystal (SCSC) oxidation/reduction, reversible structural transformations take place between the anionic porous zeolite-like Cu(I) framework and a topologically equivalent neutral Cu(I)Cu(II) mixed-valent framework. The unique conversion behavior of the Cu(I) framework endowed it as a redox-switchable catalyst for the direct arylation of heterocycle C-H bonds.

Solvent templates induced porous metal-organic materials: conformational isomerism and catalytic activity.

Solvent templates induced Co-based metal-organic materials; conformational isomers {[Co2(pdpa)(CH3CN)(H2O)3]·CH3OH·H2O}n (1) and {[Co2(pdpa)(CH3CN)(H2O)3]}n (2) and {[Co5(pdpa)2(μ3-OH)2(H2O)6]·2H2O}n (3) [H4pdpa = 5,5'-(pentane-1,2-diyl)-bis(oxy)diisophthalic acid] were synthesized under the same solvothermal conditions except with different concentrations of cyclic ethers (1,4-dioxane or tetrahydrofuran) as structure-directing agents. Structural transformations from a three-dimensional (3D) framework of 1 containing channels with dimensions of ∼6 Å × 6 Å to a two-dimensional layer structure of 2 consisting of large open channels with a size of ∼15 Å × 8 Å and then to a 3D nonporous framework of 3, resulting from the different concentrations of cyclic ethers, were observed. The anion-π interactions between electron-efficient oxygen atoms of cyclic ethers and electron-deficient dicarboxylic acid aromatic cores in H4pdpa imported into the synthetic process accounted for the conformational change of the ligand H4pdpa and the following structural variations.

Spectroscopic and crystallographic investigations of novel BODIPY-derived metal-organic frameworks.

To explore new 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-derived metal-organic frameworks (MOFs), we employed 2,6-dicarboxyl-1,3,5,7-tetramethyl-8-phenyl-4,4-difluoroboradiazaindacene (H2L) as a ligand to successfully synthesize five coordination polymers, namely, {[Zn2(L)2(bpp)]·2H2O·2EtOH}n (1), {[Cd2(L)2(bpp)]·2H2O·EtOH}n (2), {[Cd2(L)(bpe)3(NO3)2]·2H2O·DMF·EtOH}n (3), {[Cd(L)(bpe)0.5(DMF)(H2O)]}n (4), and {[Cd(L)(bpe)0.5]·1.

Copper(II) coordination polymers: tunable structures and a different activation effect of hydrogen peroxide for the degradation of methyl orange under visible light irradiation.

By tuning the synthesis conditions, based on a conformation-sensitive ligand, 1,4-bis(1,2,4-triazole-1-methylene)-2,3,5,6-tetramethyl benzene (btmx) and Cu(NO3)2·3H2O/CuCl2·2H2O, we have obtained three Cu(ii) coordination polymers with diverse structures, namely, {[Cu(btmx)2(H2O)]·2NO3}n (), {[Cu(btmx)2(Cl)2]·5H2O}n () and [Cu(btmx)(Cl)2]n (). Complex exhibits a novel 2D → 3D interpenetrating structure with a point symbol of 6(3). Complex features an irregular 2D grid with (4(4)·6(2)) topology.

Template-induced diverse metal-organic materials as catalysts for the tandem acylation-Nazarov cyclization.

In our continuing quest to develop a metal-organic framework (MOF)-catalyzed tandem pyrrole acylation-Nazarov cyclization reaction with α,β-unsaturated carboxylic acids for the synthesis of cyclopentenone[b]pyrroles, which are key intermediates in the synthesis of natural product (±)-roseophilin, a series of template-induced Zn-based (1-3) metal-organic frameworks (MOFs) have been solvothermally synthesized and characterized. Structural conversions from non-porous MOF 1 to porous MOF 2, and back to non-porous MOF 3 arising from the different concentrations of template guest have been observed. The anion-π interactions between the template guests and ligands could affect the configuration of ligands and further tailor the frameworks of 1-3.

Metal-organic frameworks based on the [1,1':3',1''-terphenyl]-3,3'',5,5''-tetracarboxylic acid ligand: syntheses, structures and magnetic properties.

The solvothermal reactions of [1,1':3',1''-terphenyl]-3,3'',5,5''-tetracarboxylic acid (H4TPTA) with transition metal cations afforded five novel coordination polymers in the presence of three pyridine ligands (4,4'-bipy = 4,4'-bipyridine, 2,2'-bipy = 2,2'-bipyridine and phen = 1,10-phenanthroline), namely [M(TPTA)0.5(4,4'-bpy)0.5(H2O)2]n (M = Co for (1), Ni for (2)), {[Mn2(TPTA)(2,2'-bpy)H2O]·1.

Structural variability, topological analysis and photocatalytic properties of neoteric Cd(II) coordination polymers based on semirigid bis(thiazolylbenzimidazole) and different types of carboxylic acid linkers.

A series of novel Cd(II) coordination complexes, formulated as {[Cd(btbb)0.5(p-phda)]·H2O}n (), [Cd(btbb)0.5(oba)]n (), {[Cd2(btbb)(m-bdc)2(H2O)]·2H2O}n (), {[Cd(btbb)0.

Guest molecule release triggers changes in the catalytic and magnetic properties of a Fe(II)-based 3D metal-organic framework.

A Fe(II)-based metal-organic framework (MOF), {[Fe2(pbt)2(H2O)2]·2H2O}n, undergoes an irreversible dehydration, which triggers changes in the catalytic and magnetic properties of the MOF. These property changes are attributed to the high-spin to low-spin transition of 7.1% center Fe(II), which is demonstrated by (57)Fe Mössbauer, X-ray photoelectron spectroscopy, and UV/vis absorption spectra.

New mechanistic insight into stepwise metal-center exchange in a metal-organic framework based on asymmetric Zn(4) clusters.

Herein, a mechanism of stepwise metal-center exchange for a specific metal-organic framework, namely, [Zn4 (dcpp)2 (DMF)3 (H2 O)2 ]n (H4 dcpp=4,5-bis(4'-carboxylphenyl)phthalic acid), is disclosed for the first time. The coordination stabilities between the central metal atoms and the ligands as well as the coordination geometry are considered to be dominant factors in this stepwise exchange mechanism. A new magnetic analytical method and a theoretical model confirmed that the exchange mechanism is reasonable.

Direct bioconversion of raw corn stalk to hydrogen by a new strain Clostridium sp. FS3.

A new strain FS3 which could achieve an efficient bioconversion of raw corn stalk to hydrogen had been isolated from anaerobic acclimated sludge, and identified as Clostridium butyricum on the basis of a series of physiological and biochemical experiments and 16S rDNA gene sequence. The strain could utilize various carbon sources to produce hydrogen. On the basis of single-factor experiments, the response surface methodology (RSM) was performed to optimize the media for hydrogen production.

Conversion from a heterochiral [2 + 2] coaxially nested double-helical column to a cationic spiral staircase stimulated by an ionic liquid anion.

The conversion from a [2 + 2] nested double-helical column, {[Mn2(ptptp)(suc)(H2O)2]·1.5H2O}n (1), to a cationic spiral staircase, {[Mn2(ptptp)(suc)0.5(H2O)3]·Br·0.

Photocatalytic H2 generation based on noble-metal-free binuclear cobalt complexes using visible-light.

Two new binuclear cobalt complexes, namely {[Co(dmgH)(dmgH2)]2L1} (I) and {[Co(dmgH)(dmgH2)]2L2} (II) (dmgH = dimethylglyoximate monoanion; dmgH2 = dimethylglyoxime, L1 = 1,3-bis(4-pyridyl)propane), L2 = 1,3-bis(imidazol-1-ylmethyl)benzene), have been synthesized by the self-assembly of [Co(dmgH)(dmgH2)] and L1 or L2, respectively. An efficient photocatalytic system was constructed by combining a noble-metal-free cobalt complex as the catalyst with Eosin Y dye (EY(2-)) as the photosensitizer to give an efficient H2 generating system under visible-light irradiation (λ > 420 nm) using triethanolamine (TEOA) as a sacrificial electron donor. The maximum amount of H2 generated was 1013 TON for I and 1134 TON for II over a 2 h irradiation period (λ > 420 nm) under the conditions of pH 8.

Post-synthetic monovalent central-metal exchange, specific I2 sensing, and polymerization of a catalytic [3×3] grid of [Cu(II)5Cu(I)4L6]⋅(I)2⋅13 H2O.

From a predesigned grid, [Cu(II)5Cu(I)4L6]⋅(I)2⋅13 H2O (1), in which LH2 was a pyrazinyl-triazolyl-2,6-substituted pyridine, we successfully synthesized an extended 3D complex, (1)∞[{Cu(II)5Cu(I)8L6}{μ-[Cu(I)3(CN)6]}2⋅2 CH3-CN] (2), that displayed unprecedented coexistence of all the five known coordination geometries of copper. Grid 1 displayed monovalent central metal exchange (CME) of Cu(I) for Ag(I) for the first time, as well as the formation of tri-iodide in the crystalline state. These systems were investigated for their magnetic properties.

Temperature-dependent capture of water molecules by saddle-shaped hexanuclear carboxylate cycloclusters in a (3,18)-connected metal-organic framework.

A new (3,18)-connected 3D metal-organic framework [Co(PYNT)(H(2)O)(2)](n) (ZZU-1) (H(2)PYNT=5-(3'-carboxylphenyl) nicotic acid) has been reported. Amazingly, ZZU-1 captures water molecules and transforms into the hydrated framework {[Co(3)(PYNT)(3)(H(2)O)(6)]⋅H(2)O}(n) (ZZU-2) at 160 °C in refluxing hydrated DMF, but not at 100 °C in refluxing neat water or from the solvothermal synthesis conducted at 90 °C.

Self-assembly of unprecedented [8+12] Cu-metallamacrocycle-based 3D metal-organic frameworks.

[8+12]-metallamacrocycle-based 3D frameworks {[Cu(4)(pbt)(2)(SO(4))(2)(DMF)(2)(CH(3)OH)]·7H(2)O·DMF}(n) (1) and [12]-macrocycle 3D {[Cu(2)(pbt)(SO(4))(DMSO)(CH(3)OH)(2)]·5H(2)O·CH(3)OH}(n) (2) have been obtained. Both complexes display antiferromagnetic couplings and high catalytic activity in the oxidative coupling reaction of 1-ethynylbenzene and oxazolidin-2-one.

Crystal structures and magnetism of infinite alternating chains arranged by paddle-wheel dinuclear copper and mononuclear copper units.

The crystal structures and magnetic properties of two novel polyclusters {[Cu(3)(tci)(2)(H(2)O)(2)]·12H(2)O}(n) (1) and {[Cu(3)(tci)(2)(H(2)O)(2)]·6H(2)O}(n) (2) (tci = tris(2-carboxyethyl) isocyanurate) are investigated. The X-ray crystallographic analysis reveals that they contain interesting infinite alternating chains of dinuclear paddle-wheel copper and mononuclear copper units arranged in ABBA magnetism exchange mode. Variable-temperature magnetic susceptibility measurements on the two polyclusters show strong antiferromagnetism couplings between copper ions with exchange interactions J = -181.

A precise hexagonal octadecanuclear Ag macrocycle with significant luminescent properties.

The first hexagonal octadecanuclear Ag macrocycle [Ag(18)(TTTMB)(12)](NO(3))(18)·30H(2)O has been hydrothermally synthesized. The outside and inner diameters of the unprecedented architecture are about 27.72(13) Å and 15.