Syntheses,structures,and properties of three coordination polymers based on 5⁃ethylpyridine⁃2,3⁃dicarboxylic acid and N⁃containing ligands

Three coordination polymers[Mn(epda)(2,2'⁃bipy)(H_(2)O)](1),[Mn(epda)(phen)](2),and[Co_(2)(epda)2(bpe)2(H_(2)O)_(4)]·5H_(2)O(3)(H2epda=5⁃ethyl⁃pyridine⁃2,3⁃dicarboxylic acid,2,2'⁃bipy=2,2'⁃bipyridine,phen=phenanthroline,bpe=1,2⁃bis(4⁃pyridyl)ethylene)were synthesized by solvothermal reactions and characterized by single⁃crystal X⁃ray diffraction,thermogravimetric analyses,IR spectroscopy and elemental analysis.1 displays a 1D chain struc⁃ture,and these chains are joined by O-H…O hydrogen bonding andπ⁃πstacking interactions to generate a 2D layer structure.2 displays a 2D layer structure,and adjacent layers are generated 3D architecture throughπ⁃πstacking interactions.3 displays a 1D chain structure,and adjacent chains are generated double layer structure through O-H…O hydrogen bonding.The fluorescent properties of 1 and 3 indicate that they can potentially be used as a luminescent sensor.1 was highly selective and sensitive towards o⁃nitrophenol through different detection mechanisms,however,3 was highly selective and sensitive towards 2,4,6⁃trinitrophenol.In addition,the magnetic behavior of 2 has also been investigated.CCDC:2172533,1,2355773,2,2355774,3.

Synthesis, Crystal Structure and Properties of a New Zn(II) Coordination Polymer Constructed from 2,3-Pyridine Dicarboxylic Acid and 1,1′-(1,4-Butanediyl)bis(imidazole)

A new coordination polymer, namely [Zn（pdc）（bbi）]n {H2 pdc = 2,3-pyridine dicar- boxylic acid, bbi = 1,1-（1,4-butanediyl）bis（imidazole）}, has been prepared under hydrothermal conditions and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21 /n with a = 8.436（3）, b = 16.988（5）, c = 12.106（4）, β = 92.204（5）°, V = 1733.6（9）3, Z = 4, C17 H17 N5 O4 Zn, Mr = 420.73, Dc = 1.612 g/cm3, F（000） = 864, μ（MoKa） = 0.452 mm-1, the R = 0.0672 and wR = 0.1645. In the mononuclear complex, each Zn（II） is five-coordinated by one carboxylate O and one pyridyl N atoms from one pdc anion, one carboxylate O atom from another pdc anion, and two N atoms from two bib ligands. The Zn（II） ions are connected by pdc ligands to form skeleton chains, and bbi ligands further link them to construct a 2D framework. The thermal and luminescence properties of the complex were also investigated.

Syntheses, Structures and Magnetic Properties of Two Co(II) Coordination Polymers with 2,5-Pyridine Dicarboxylic Acid

The hydro(solvo)thermal reactions of cobalt powder or its chloride with 2,5- pyridine dicarboxylic acid (H2PYDC) yielded two new complexes: [Co(II)2(PYDC)2(H2O)2- (H2O)4]n 1 and {Co(II)[NH2(CH3)2]2(PYDC)2}n 2. It is observed that the reactive solvents result in different connectivity modes of ligand and diverse dimensional extension of crystal structures. The correlation between structure and magnetic property will be discussed in this paper. Crystal data for 1: space group P1, a = 7.0419(17), b = 8.937(2), c = 9.6182(19) ?, α = 91.532(4), β = 99.869(10), γ = 107.889(11)o, V = 565.5(2) ?3, Z = 1, Dc = 1.845 g/cm3, μ = 1.56 mm-1, F(000) = 322 , R = 0.0505 and wR = 0.1580; and those for 2: space group C2/c, a = 14.9075(6), b = 8.2523(3), c = 16.9643(2) ?, β = 100.982(2)o, V = 2048.75(11) ?3, Z = 4, Dc = 1.560 g/cm3, μ = 0.892 mm-1, F(000) = 996, R = 0.0443 and wR = 0.1134.

Separation Behavior of U(VI) and Th(IV) on a Mixed Ion Exchange Column Using 2,6-Pyridine Dicarboxylic Acid as a Complexing Agent and Determination of Trace Level Thorium in Uranium Matrix Employing High Performance Ion Chromatography

Retention behavior of U(VI) and Th(IV) as their 2, 6-pyridine dicarboxylic acid (PDCA) complexes on reversed phase and ion exchange (cation, anion and mixed ion exchange) columns was studied and based on the results, a simple ion chromatography method for the determination of trace level thorium in uranium oxide using 0.075mM 2, 6-pyridine dicarboxylic acid (PDCA) and 1M KNO3 in 1.2M HNO3 as eluent (flow rate 1 mL/min)was proposed. The advantage of the developed method is that the separation of uranium matrix is not required prior to the ion chromatographic determination of trace Th. Separation was carried out on a mixed ion exchange stationary phase and a 10?4 M arsenazo (III) solution was used as post column reagent for detecting the separated metal ions. The separation of Th from uranium using PDCA in the present investigation is attributed through cation exchange mechanism. A calibration plot was constructed by following the standard addition method over the concentration range of 0.25 to 10 ppm of Th in the presence of uranium matrix, which resulted in a linear regression coefficient of 0.9978. The precision of the method was better than 5% and the LOD for Th was found to be 0.1ppm (S/N=3). The method has been validated by comparing the results with the results obtained from ICP-MS analysis where the This separated from the uranium matrix. The proposed method is simple, rapid, accurate and cost effective compared to techniques like ICP-MS or ICP-AES and is suitable for the routine kind of analysis.

An efficient electrocatalytic system composed of nickel oxide and nitroxyl radical for the oxidation of bio-platform molecules to dicarboxylic acids

Selective oxidation of biomass and its derivatives to dicarboxylic acids represents a promising route for biomass valorization.However,the co-presence of multiple functional groups in biomass molecules makes the selective oxidation of particular functional a challenging task.Here,we demonstrate an efficient electrocatalytic system consisting of nickel oxide(NiO)and a nitroxyl radical,i.e.,2,2,6,6-tetrame thylpiperidine-1-oxyl(TEMPO)or 4-acetamido-TEMPO(ACT),for the selective oxidation of key bioplatform molecules including glucose,xylose and 5-hydroxymethylfurfural(HMF)into corresponding dicarboxylic acids,i.e.,glucaric acid,xylaric acid,and 2,5-furandicarboxylic acid(FDCA).NiO is clarified as the active catalyst for the oxidation of aldehyde in bio-platform molecules to carboxylic acid,while TEMPO or ACT is responsible for the oxidation of primary alcohol to aldehyde.The combination of NiO and TEMPO or ACT significantly accelerated the tandem oxidation of aldehyde and hydroxyl groups in glucose,xylose and HMF,thus achieving excellent yields(83%-99%)of dicarboxylic acids.Moreover,the combination catalyst enables the selective oxidation of glucose and xylose with high concentrations(e.g.,20 wt%),which offers a promising strategy for biomass valorization.

Synthesis,Electrochemical and Fluorescent Properties of a New Zinc(Ⅱ) Complex through Self-assembly Reaction of 2,2'-Bipyridine-3,3'-dicarboxylic Acid

A new Zn（Ⅱ） complex [Zn（Phen）2（C（12）H6O4N2）（H2O）]·3H2O with 2,2-bipyridine-3,3-dicarboxylic acid and 1,10-phenanthroline（Phen） as ligands was synthesized, and the crystal data are as follows： monoclinic, space group P2（1/n）, a=12.5581（11）, b=17.3382（17）, c=15.6687（14） , β=110.579（2）o, Mr=731.02, V=3193.9（5） 3, Dc=1.520 g/cm3, Z=4, μ（Mo Kα）=0.833 mm（-1）, F（000）=1508, the final R=0.0431 and w R=0.0936. In the title complex, the central Zn（Ⅱ） ion is located in a distorted octahedral coordination environment. The electrochemical and fluorescent properties were studied. The title complex possesses irreversible electron transfer in the electrode reaction, and it has a strong emission peak in the range of 470505 nm, with the excitation wavelength being 488 nm.

NMR Studies on Eu and La Complexes with Pyridine-2,6-Dicarboxylic Acid and Phen

The binary and ternary solid complexes of Eu 3+ and La 3+ with pyridine 2,6 dicarboxylic acid (H 2DPC) and 1,10 phen anthroline were synthesized. Their compositions confirmed by elemental analysis are Na 3[Ln(DPC) 3]·2H 2O(Ln=La, Eu) and NaEu(DPC) 2·phen·4H 2O. The coordination mode of ligands with metal ions was studied by NMR. The influences on NMR spectra by induciton effect, screening effect and paramagnetic character of rare earth ions are discussed in this paper. The NMR studies show that these three complexes have similar symmetry and regular change of chemical shifts. Pyridine 2,6 dicarboxylic acid is a tridentate ligand. The coordination number of europium and lanthanum is nine in each of the binary complexes. The coordination number of europium is at least eight in the ternary complex.

Formation of [3]Pseudorotaxanes from β-cyclodextrin and a Series of Dicarboxylic Acids with Their Corresponding α,ω-alkanedicarboxylate Anions

Inclusion complexes between β-cyclodextrin （β-CD） and a series of dicarboxylic acids （DAn, n=11-15） were prepared by co-grinding and co-precipitation methods and the [3]pseudorotaxane structure of them was elucidated by FTIR, DTA and XRD characterizations. Inclusion complexes of β-CD and α,ω-alkanedicarboxylate anions （DAn^2-） were acquired by neutralizing β-CD/DAn different inclusion complexes with sodium hydroxide and the structure was also proved to be a pseudorotaxane structure by ^1H-NMR spectra and NOESY spectrum. Both the inclusion complexes of β-CD/DAn and β-CD/DAn^2- adopt the [3]pseudorotaxane structure with β-CD arranged in dimers threaded onto one aliphatic chain and the binding mode of 1：1 inclusion complex was excluded based on the consideration of chain conformations.

Luminescence of Terbium Chelates with Substituted Pyridine-2, 6-Dicarboxylic Acid Derivatives by Synergistic Effect of EDTA

Some spectral properties and luminescence intensities of Tb 3+ chelates of substituted pyridine 2, 6 dicarboxylic acids and 4 phenyl pyridine 2, 6 dicarboxylic acid analogues were measured in some solutions (H 2O and EtOH etc.) by synergistic effect of EDTA. The substitution at the aromatic ring has a significant effect upon the observed luminescence intensities, excitation wavelengths, and lifetime of the complexes. Moreover, the changes in the environment cause great variation in those properties of certain Tb 3+ chelates. The results show that some of hte chelates (4 acetaminopoxypyridine 2, 6 dicarboxylic acid, 4 ethoxypyridine 2, 6 dicarboxylic acid and 4 methoxypyridine 2, 6 dicarboxylic acid etc.) have a stronger emission and longer lifetime at room temperature and may thus be used as perfectly sensitizers in fluorescence analysis.

Microcomputer Simulation of Elution Behaviour for Dicarboxylic Acids in Ion－Exclusion Chromatography

he present paper covers a model involving Donnan memhrane equilibrium andadsorption eluilibrium to describe the retention process for diprotic organic acids inion-exclusion chromatography. On this basis the microcomputer simulation of elu-tion behaviour for dicarboxylic acids was investigated. Influences of eluent acidityand sample concentration on the retention value were studied. The theoreticallypredicted results are in reasonable agreement with the experimental data.

Crystal Structure of Dimeric Units Cd_2(ncpo)_2(phen)_2(H_2O)_2 Constructed by Flexible Dicarboxylic Acid with Fluorescent Emission

A dimeric coordination complex Cd2（ncpo）2（phen）2（H2O）2 was constructed by a flexible dicarboxylic acid, 2-nitro-4-carboxylphenoxyacetic acid. Its crystal structure was determined by X-ray single-crystal diffraction analysis. The crystal is of monoclinic system, space group P21/n with a = 17.2616（3）, b = 12.7460（2）, c = 18.4041（3） A^°, β= 94.432（1）°, C42H30Cd2N6O16, Mr = 1099.52, V = 4037.09（12）A^°^3 Dc = 1.809 g/cm^3, F（000） = 2192, μ = 1.139 cm^-1 and Z = 4. The final R = 0.0218 and wR = 0.0703 for 8288 observed reflections with I 〉 2σ（I）. There are two crystallographically independent but structurally very similar molecules in the unit cell of the title complex. It is noticeable that the ligand ncpo^2- displays a good flexibility, demonstrating different modes from the rigid ligands. The luminescence property has been investigated, which shows photoluminescence at 465, 490 and 574 nm upon excitation at 320 nm in the solid state at room temperature.

Engineering Chitosan Using <i>α</i>, <i>ω</i>-Dicarboxylic Acids—An Approach to Improve the Mechanical Strength and Thermal Stability

The current scenario in tissue engineering research demands materials of requisite properties, viz., high porosity, mechanical stability, thermal stability, biocompatibility and biodegradability for clinical applications. However, bringing these properties in single biomaterial is a challenging task, which needs intensive research on suitable cross-linking agents. In the present study, 3D scaffold was prepared with above said properties using chitosan and oxalic (O), malonic (M), succinic (S), glutaric (G), adipic (A), pimelic (P), suberic (SU), azelaic (AZ) and sebacic (SE) acid (OMS- GAP-SAS) individually as a non covalent cross-linkers as well as the solvent for chitosan. Assessment on degree of cross-linking, mechanical strength, FT-IR analysis, morphological observation, thermal stability, binding interactions (molecular docking), in vitro biocompatibility and its efficacy as a wound dressing material were performed. Results revealed the degree of cross-linking for OMSGAP-SAS engineered chitosan were in the range between ≈55% - 65% and the biomaterial demonstrated thermal stability more than 300°C and also exhibited ≥3 - 4 fold increase in mechanical strength compared to chitosan alone. The bioinformatics studies evidently proved the chemistry behind the interaction of OMSGAP-SAS with chitosan. OMSGAP-SAS played dual role to develop the chitosan biomaterial with above said properties, thus matching the requirements needed for various applications.

Synthesis,Structure and Photoluminescence of a New Ir Complex Based on Pyridine-2,3-dicarboxylic Acid

A new complex Ir（ppy）2（Hpda）（Hppy=2-phenylpyridine, H2pda=pyridine-2,3-dicarboxylic acid） has been synthesized and characterized. According to single-crystal X-ray diffraction analyses, the title complex crystallizes in the monoclinic system, space group P21/n with a=8.5708（10）, b=22.685（2）, c=12.5722（15） , β=96.19（1）°, V=2430.2（5） 3, C（29）H（20）N3O4 Ir, Mr=666.22, Z=4, Dc=1.833 g/cm3, F（000）=1304, μ=5.54 mm（-1）, λ（Mo Kα）=0.71073 , GOOF=1.02, the final R=0.049 and w R=0.119 for 4680 independent reflections with Rint=0.069. The title complex is of mononuclear structure. Intermolecular C–H···O hydrogen bonds and π-π stacking interactions result in the formation of a 3D supramolecular network. Photoluminescent spectra show that one intense emission band with the maximum of 516 nm can be observed in the title complex.

Effect of dicarboxylic acid esters on the lubricity of aviation kerosene for use in CI engines

To reduce their fuel related logistic burden,North Atlantic Treaty Organization(NATO)Armed Forces are advancing the use of a single fuel for both aircraft and ground equipment.To this end,F-34(the commercial equivalent is Jet A-1)is replacing distillate diesel fuel in many applications.However,tests conducted with this kerosene type on high frequency reciprocating rig showed that this type of fuel causes unacceptable wear.This excessive wear is caused by the poor lubricity of aviation fuel.In order to make this type of fuel compatible with direct injection compression engines,seven di-carboxylic acid esters have tested to improve the lubricity of kerosene.Tribological results showed that all esters tested in this series of experiments seem to be suitable for increasing the kerosene lubricity to a satisfactory level.

Two Copper-organic Frameworks Constructed from the Flexible Dicarboxylic Ligands

Two new copper-organic frameworks [Cu4(L^1)4(DMF)4·2DMF]n(DZ-1) and [Cu(L^2)(DMF)]n(DZ-2)(H2L^1 = 2,2'-(1,4-phenylenebis(methylene))bis(sulfanediyl)dinicotinic acid and H2L^2 = 2,2'-(1,2-phenylenebis(methylene))bis(sulfanediyl)dinicotinic acid) have been synthesized and characterized. DZ-1 with a zero-dimensional structure crystallizes in monoclinic crystal system, space group P21/n with a = 17.1697(11), b = 17.1241(11), c = 18.8638(14) ?, V = 5193.2(6) ?~3, Z = 2, Dc = 1.493 g·cm^(-3), μ = 1.046 mm^(-1), F(000) = 2408. All L^1 ligands adopted syn-conformation. DZ-2 is a two-dimensional structure crystallized in monoclinic crystal system, space group P21/n with a = 11.855(5), b = 18.601(8), c = 12.319(5) ?, V = 2400.4(18) ?~3, Z = 4, Dc = 1.514 g·cm^(-3), μ = 1.124 mm^(-1), F(000) = 1124. The selective sorption of CO2 over N2 for DZ-1 was found.

The synthesis of dialdehydes from dicarboxylic acids via imidazolines

DIALDEHYDES are important chemical industrial materials, which are widely used in textile,medicine, dye, binder, coating and so on. The traditional method for preparing dialdehydes is the catalytic oxidation of glycol. We have reported the reduction ring-opening reaction of inndazoline by NaBH4.In this note, the reduction of imidazoline by sodium and ethanol is studied. A new synthetic method for the preparation of dialdehydes from dicarboxylic acids

Immobilization of pyrene on quartz plate surface via a flexible long spacer and its sensing properties to dicarboxylic acids

A novel photo-induced luminescence film has been prepared by immobilizing pyrene on quartz plate surface via a flexible long spacer, 1,3-diaminopropane and 3-glycidoxypropyl trimethoxysilane. The film shows combined monomer and excimer emission of pyrene in both wet and dry states. Steady-state and time-resolved fluorescence emission meas-urements demonstrated that the excimer emission mainly came from direct excitation of ground state dimers, and/or monomers in aggregated state. Classical Birks?scheme plays little role in the formation of the excimers. The structures of the excimers formed during the excitation are complex. Both standard excimer of sandwich-like fully overlapped structure and distorted ex-cimer of partially overlapped structure exist in the excited state of the fluorophore. The emission of the film is sensitive to the presence of dicarboxylic acids, including ethanedioic acid, malonic acid, succinic acid, etc. The emission in the monomer and excimer region increases along with increasing the concentration of the dicarboxylic acids. The time needed for the emission to reach equilibrium depends on the nature of the acids. It has been shown that the longer the chain length of the acids, the more the time needed. This observation is explained by considering the conformational reorganization of the immobilized pyrene due to insertion of the dicarboxylic acids into the space between neighboring spacers. Experimental results from similar studies using formic acid and acetic acid are in support of this explanation. Furthermore, the response of the film to dicarboxylic acids is reversible.

Synthesis,Structures,Luminescence and Catalytic Activity in the Knoevenagel Condensation Reaction of Two Cd(Ⅱ)Coordination Polymers Based on a Biphenyl-dicarboxylic Acid

Two cadmium(II)coordination polymers,namely[Cd(μ-dda)(H2 biim)]n(1)and[Cd(μ4-dda)(py)]n(2)have been constructed hydrothermally using H2 dda(H2 dda=4,4?-dihydroxybiphenyl-3,3?-dicarboxylic acid),H_(2)biim(H_(2)biim=2,2?-biimidazole),py(py=pyridine),and cadmium chloride at 160°C.The products were isolated as stable crystalline solids and were characterized by IR spectra,elemental analyses,thermogravimetric analyses(TGA),and single-crystal X-ray diffraction analyses.Single-crystal X-ray diffraction analyses revealed that both compounds crystallize in the monoclinic system,space group C2/c.Compound 1 discloses a 1 D chain structure.Compound 2 features a 3 D framework.The luminescent properties of compounds 1 and 2 were evaluated.Besides,the catalytic activities in the Knoevenagel condensation reaction of two compounds were investigated.Compound 1 exhibits an excellent catalytic activity in the Knoevenagel condensation reaction at room temperature.

Two Co(Ⅱ)Complexes Constructed from 1-(3,5-Dicarboxybenzyl)-3,5-pyrazole Dicarboxylic Acid:Syntheses,Structures and Magnetic Properties

Two new complexes[Co_(2)(L)(4,4´-bip)(H_(2)O)_(3)]_(n)(1)and{[Co(L´)_(2)(phen)]·2H_(2)O)}_(n)(2)(H_(4)L=1-(3,5-dicarboxybenzyl)-3,5-pyrazole dicarboxylic acid,H_(3)L´=1-(3,5-dicarboxybenzyl)-3-pyrazole carboxylic acid,4,4´-bip=4,4´-bis(1-imidazolyl)biphenyl,phen=1,10-phenanthroline)were synthesized.Complexes 1 and 2 have been characterized by IR spectrography,X-ray single-crystal diffraction,elemental analysis and thermogravimetry.1 crystallizes in monoclinic system,space group P2_(1/c).Complex 2 crystallizes in monoclinic system,space group I2/a.It is remarkable that in situ hydrothermal decarboxylation was observed during preparing complex 2.In addition,magnetic analysis indicates that antiferromagnetic interaction exists among Co(Ⅱ)ions in complexes 1 and 2.