Synthesis, Spectral and Electrochemical Studies of Complex of Uranium(IV) with Pyridine-3-Carboxylic Acid

The investigation of complexation of uranium with biological active ligands is vital for understanding uranium speciation in biosystems. A number of studies have been undertaken for investigating the complexation of uranium in its (VI) oxidation states but similar investigations pertaining to the interaction of uranium, in lower oxidation states, with biological ligands is scarce. The aim of the work is to bridge this gap and studies have been carried out to determine the coordination pattern of pyridine-3-carboxylic acid with uranium(IV). Semi-micro analysis, spectro-analytical techniques, magnetic susceptibility and cyclic voltammetry have been employed for the characterization of the synthesized complex.

Green Chemistry Approach to Fast and Highly Efficient One-Pot Synthesis of Bis-Isoxazolyl-1,2,5,6-Tetrahydro Pyridine-3-Carboxylates

The synthesis of the bis-isoxazolyl-1,2,5,6-tetrahydro pyridine-3-carboxylates is achieved in high yield without the production of toxic waste products by using room temperature ionic liquid (RTILs) triethyl ammonium acetate (TEAA). The RTIL TEAA played the dual role of efficient green solvent as well as recyclable catalyst.

THE FIRST BINUCLEAR MOLYBDENUM AND TUNGSTEN COMPLEXES WITH DOUBLY-BRIDGING PYRIDINE-2-THIOLATO LIGANDS.X-RAY CRYSTAL STRUCTURE OF THE COMPLEX[Mo_2(CO)_4(μ-pyS)_2(PPh_3)_2].2C_7H_8

The title complex was obtained by reactions of [Mo(CO)_3(MeCN)_3] with [CuBr(pySH)(PPh_3)_2]or directly with pySH and PPh_3. The latter method can be used to synthesize the corresponding tungsten complex [W_2(CO)_4(μ-pyS)_2(PPh_3)_2].The molecular structure of the title compound was determined by X-ray diffraction method.

Theoretical Study on the Reaction Mechanism of 2-Methoxybenzaldehyde,4-Bromo-indanone,Malononitrile and Ammonium Acetate One-pot to Form 6-(2-Methoxyphenyl)-2-amino-6-bromo-5H-indeno[1,2-b]pyridine-3-carbonitrile

The reaction mechanism of 2-methoxybenzaldehyde, 4-bromo-indanone, malononitrile and ammonium acetate one-pot to form 6-（2-methoxyphenyl）-2-amino-6-bromo-5 Hindeno[1,2-b]pyridine-3-carbonitrile was studied by density functional theory. The geometries of the reactants, transition states, intermediates and products were optimized at the PW91/DNP level. Vibration analysis was carried out to confirm the transition state structure. Reaction pathways were investigated in this study. The result indicates that the reaction Re→ TSB1→IMB1→ TSB2→ IMB2→TSB3→IMB3→TSB4→IMB4→TSB5→IMB5→TSB6→IMB6→TSB7→IMB7→ TSB8→IMB8→TSB9→IMB9→P2 is the main pathway, the activation energy of which is the lowest. The dominant product predicted theoretically is in agreement with the experiment results.

1D Lanthanide Coordination Polymers Based on 3-(Pyridin-4-yl)benzoic Acid: Syntheses, Structures and Luminescent Properties

ABSTRACT Four novel 1D lanthanide coordination polymers with formula [Ln（3,4-pybz）3（HzO）2. H2O]n （Ln = 1 Sm; 2 Eu; 3 Tb; 4 Dy, 3,4-Hpybz = 3-（pyridin-4-yl）benzoic acid） have been synthesized by hydrothermal reactions of lanthanide oxide and 3-（pyridine-4-yl） benzoic acid. Single-crystal X-ray diffraction shows that the four compounds are isostructural. They all crystallize in a monoelinic system, space group P1^-. They have a doubly carboxylate-bridged infinite-chain structure with alternating Ln-（carboxylate）2-Ln linkages and one chelating carboxylate group on each metal center. The Ln ion also combines to two water molecules to form an eight-coordinate square antiprismatic geometry. The pyridine nitrogen atoms of the ligand do not coordinate to the metal centers but direct the formation of a 3D network through hydrogen bonding with coordinated water molecules. The photoluminescent properties of 2 and 3 have been also studied.

Synthesis and Crystal Structure of a One-dimensional Infinite Chain Organotin Complex [(n-Bu)_3Sn(OCOC_5H_4NO)]_n

A novel organotin complex [（n-Bu）3Sn（OCOC5H4NO）]n has been synthesized and characterized by elemental analysis, IR and ^1H NMR. The crystal structure has been determined by X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group P2 1/c with a = 8.982（2）, b = 17.908（4）, c = 13.219（3） A, β= 96.981（4）°, Z = 4, V= 2110.6（8） A^3, Dc = 1.347 g/cm^3, μ（MoKa） = 12.23 cm^-1, F（000） = 880, R = 0.0497 and wR = 0.1263. In the molecular structure of the title complex, the tin atoms are five-coordinated in a distorted trigonal bipyramidal geometry. A one-dimensional linear polymer is formed through an interaction between the O atoms of pyridine-3-carboxylic acid N-oxide and tin atoms of an adjacent molecule.

Relationship between Coordination Structure and Biological Activity of Copper(II) Nicotinate

The copper（Ⅱ） complexes of pyridine-3-carboxylic acid （nicotinic acid） and pyridine-2-carboxylic acid （isonicotinic acid） were synthesized, and their structures were characterized by elemental analysis, infrared spectrum, powder X-ray diffraction and so on. The results show that under experimental conditions, the ligands of synthesized copper nicotinate and copper isonicotinate are coordinated simultaneity with copper（Ⅱ） via the nitrogen of pyridine group and an oxygen of carboxylic acid group to form bidentate chelates. The crystal of copper nicotinate with two six-membered chelate rings belongs to monoclinic system, while that of copper isonicotinate having two five-membered chelate rings is of triclinic system. The tests show that the biological activities, such as the improvement of feed utilization, growth, anti-oxidation ability of organism and disease-resistant power, are different when copper nicotinate, copper inicotinate, copper-lysine chelate, copper-methionine chelate and copper sulphate are added in pig＇s feed, respectively. Due to its higher biological activity, less pollution and lower toxicity, copper nicotinate has wide potential applications as a feed additive.

Synthesis and Structural Characterization of a Supramolecular Compound [(C_8H_9NO_2)·HgI_2]_n Constructed from Hg…I and C–H…O Linkage

The title complex [（C8H9NO2）·HgI2]n has been synthesized from the reaction of pyridine-3-ethylformate with mercury iodide in the mixture of DMF and absolute methanol. Its structure was determined by IR, elemental analysis and X-ray single-crystal diffraction analysis. The crystal is of monoclinic system, space group P21/n with a = 4.3397（5）, b = 25.051（3）, c = 12.3719（13）A, β = 92.2130（10）°, CsH9HgI2NO2, Mr = 605.55, V = 1344.0（3）A^3, Z = 4, Dc = 2.993 mg·m^-3, F（000） = 1064, μ = 16.024 mml, the final R = 0.0258 and wR = 0.0504. In the title complex, the center Hg（II） exhibits a four-coordinated distorted tetrahedral geometry. A three-dimensional network arrangement is presented via Hg…I weak interactions among adjacent molecules.

Dimethylformamide Dimethyl Acetal (DMFDMA) in Heterocyclic Synthesis: Synthesis of Polysubstituted Pyridines, Pyrimidines, Pyridazine and Their Fused Derivatives

Reaction of N,N’-dimethylformamide dimethyl acetal (DMFDMA) with malononitrile dimer 8 (1:1) mole afforded 9 while, this reaction when carried out in (2:1) mole to give amidine 11 which can be used for the preparation of pyrimidine 13, amidine 14 and pyridine 19 when reacted with 4-nitroaniline, 4-methylaniline and alkoxide respectively. Malononitrile dimer reacted with diazonium chloride to give pyridazine 21, which can be reacted with DMFDMA, AcOH/HCl and cyanoacetamide to give pyridazine 22, 23 and pyrido[4,3-c] pyridazine 24 respectively. The latter reacted with DMFDMA to afford tricyclic compound 25.

PdCl_2-catalyzed heterocyclotrimerization in MeOH/scCO_2:A versatile approach to dimethyl pyridine-3,5-dicarboxylate from methyl acrylate and urea

A novel and green method for the synthesis of dimethyl pyridine-3,5-dicarboxylate has been developed. It is PdCl2-catalyzed heterocyclotrimerization of methyl acrylate with urea in methanol/supercritical carbon dioxide. The target compound was obtained with a 75% isolated yield under the optimized con-ditions.

Synthesis and Crystal Structure of an Acetate Radical Bridged Dinuclear Copper(Ⅱ) Complex

A new acetate radical bridged dinuclear copper（ Ⅱ ） complex [（C8H9NO2）2- Cu2（CH3COO）4] has been synthesized by the reaction of Cu（OAc）2 with pyridine-3-ethyl formate and further characterized by X-ray single-crystal diffraction. Crystal data for the title compound： triclinic system, space group Pí, with a = 8.1654（14）, b = 9.7010（16）, c = 9.9005（17） A, α = 83.266（2）, β = 78.887（2）, γ = 72.881（2）°, V= 733.9（2） A^3, Mr = 665.58, Z = 1, Dc = 1.506 g/cm^3, F（000） = 342,μ = 1.510 mm^-1, the final R = 0.0392 and wR = 0.1005. According to the structural determination, each unit of the title compound is composed of two Cu（ Ⅱ ） atoms, two pyridine-3-ethyl formate molecules and four acetate ions. Each Cu（Ⅱ） coordinates to oxygen atoms of acetate and nitrogen atoms of pyridine- 3-ethyl formate ligand to give a six-coordinate distorted octahedral geometry. It is worth mentioning that strong Cu-Cu bond can be observed in the title compound.

Synthesis, Crystal Structure and Luminescence of a New Europium(Ⅲ) Coordination Polymer with Imidazole Carboxylic Ligand

A new luminescent compound, {[Eu3（L）4（H2 O）8]·（NO3）·4 H2 O}n（1, H2 L = 2-（pyridine-3-yl）-imidazole-4,5-dicarboxylic acid） has been solvothermally synthesized and structurally characterized by elemental analyses, IR and single-crystal X-ray diffraction. 1 crystallizes in monoclinic, space group C2/c with a = 21.0183（19）, b = 9.5227（6）, c = 28.227（3） ?, β = 106.885（5）o, V = 5406.1（8） ?3, Dc = 2.038 g/cm3, μ = 3.358 mm-1, Mr = 1658.76, F（000） = 3247, Z = 4, the final R = 0.0488, wR = 0.1195 and S = 1.075. The deprotonated L ligand employs a μ4-bridge to coordinate with three Eu（Ⅲ） ion, forming a wave-like（3,4）-connected 2 D structure. The existence of π···π interaction between the pyridine rings of L ligands leads to an infinite 3 D network. Furthermore, the thermal analysis, powder diffraction and solid-state photoluminescent properties of compound 1 have also been investigated.