Synthesis,structure and thermochemical study of a cobalt energetic coordination compound incorporating 3,5-diamino-1,2,4-triazole and pyridine-2,6-dicarboxylic acid

An energetic coordination compound [Co₂(C₂H₅N₅)₂(C₇H₃NO₄)₂(H₂O)₂]·2H₂O (Hdatrz(C₂H₅N₅) = 3,5-diamino-1,2,4-triazole, H₂pda(C₇H₅NO₄) = pyridine-2,6-dicarboxylic acid) has been synthesized and characterized by elemental analysis, chemical analysis, IR spectroscopy, single-crystal X-ray diffraction and thermal analysis. X-ray diffraction analysis confirmed that the compound possessed a di-nuclear unit and featured a 3D super-molecular structure. Furthermore, a reasonable thermochemical cycle was designed based on the preparation reaction of the compound and the standard molar enthalpy of dissolution of reactants and products was measured by the RD496-2000 calorimeter. Finally, the standard molar enthalpy of formation of the compound was determined to be −(2475.0 ± 3.1) kJ · mol⁻¹ in accordance with Hess’s law. In addition, the specific heat capacity of the compound at T = 298.15 K was determined to be (1.13 ± 0.02) J · K⁻¹ · g⁻¹ by RD496-2000 calorimeter.     

Investigation of regioselectivity on the reaction of 5-bromo-2,4-dichloro-6-methylpyrimidine with ammonia

Regioselective displacement reaction of ammonia with 5-bromo-2,4-dichloro-6-methylpyrimidine was studied by X-ray crystallography analysis and showed the formation of 5-bromo-2-chloro-6-methylpyrimidin-4-amine as a main product. Reaction of the latter compound with secondary amines in boiling ethanol afforded 4-amino-5-bromo-2-substituted aminopyrimidines. The synthesized compound in this paper crystallized in the monoclinic crystal system space group P2₁/n. In the title cocrystal, 5-bromo-2-chloro-6-methylpyrimidin-4-amine·3H₂O, the asymmetric unit contains one crystallographically independent 5-bromo-2-chloro-6-methylpyrimidin-4-amine and three crystallization of water molecules. The typical intramolecular O−H⋯N as well as O−H⋯O hydrogen bond is observed in the crystalline network of the title compound. It is interesting to point out that the crystal structure is further stabilized by O−H⋯O hydrogen bonds created by (H₂O)_∞ clusters.     

Copper(II) complexes with pyridine-2,6-dicarboxylic acid from the oxidation of copper(I) iodide

Via an oxidation reaction of Cu(I) iodide with pyridine-2,6-dicarboxylic acid (H₂L) in DMF three copper(II) complexes, [(CH₃)₂NH₂]₂[CuL₂] (1), K₂[CuL₂]?H₂L?H₂O (2) and [Cu(L)(H₂O)]_n (3), were synthesized and characterized. The structures of 1–3 were determined by single crystal X-ray diffraction studies. In-situ DMF decomposition produces dimethylamine base under solvothermal conditions and a proton transfer reaction takes place for the complex formation of 1. 3-D networks are stabilized in 1 and 2 via hydrogen bonds. Complex 3 is a 1-D coordination polymer with Cu-O semi-coordination bonds. Thermal decomposition of the complexes results in the corresponding metal oxides. Also, the electrochemical behavior of 1 was determined to be a metal-centered and diffusion-controlled, one-electron reduction process.     

Syntheses of crystal structures and in vitro cytotoxic activities of new copper(II) complexes of pyridine-2,6-dicarboxylate

[Cu(pydc)(im)]_n (1), [Cu(pydc)(mim)₃]?2H₂O (2), [Cu(pydc)(ampy)(H₂O)]?H₂O (3), and [Cu(pydc)(phen)][Cu(Hpydc)₂] (4) (H₂pydc = 2,6-pyridinedicarboxylic acid or dipicolinic acid, im = imidazole, mim = 2-methylimidazole, ampy = 2-amino-4-methylpyridine, and phen = 1,10-phenanthroline) were synthesized and characterized by elemental analysis, spectroscopic measurements (UV–vis and IR spectra) and single crystal X-ray diffraction. Complexes 1, 2 and 3 were studied by thermogravimetric analysis from ambient temperature to 1100 K under nitrogen and thermal stabilities were investigated. The effects of complexes on proliferation of fibrosarcoma cells were investigated using the Quick Cell Proliferation Assay. The cell viability changes depend on the concentrations and type of complexes. According to cell proliferation/viability data, 4 was determined to be the most cytotoxic.     

Synthesis and characterization of two temperature-dependent copper(II) complexes based on 2,6-dimethylpyridine-3,5-dicarboxylate

Two temperature-dependent Cu(II) compounds, [Cu(mpdaH)₂(H₂O)₄] · 4H₂O (1) and [Cu(mpdaH)₂] _n (2) (H₂mpda = 2,6-dimethylpyridine-3,5-dicarboxylic acid), have been synthesized under hydrothermal conditions and characterized by X-ray single crystal diffraction, elemental analysis, thermogravimetric analyses, and IR spectra. The structure at room temperature confirms that 1 is mononuclear with the octahedral coordination geometry. However, on warming to 120°C the same reaction gives 2, in which copper(II) has square planar coordination and is further bridged by mpdaH^? ligands to form extended 2-D layers with parallelogram-like (4,4) topology. Furthermore, in both complexes, through π–π stacking and hydrogen bonding interactions, 3-D supramolecular networks are assembled.     

The Crystal and Molecular Structure of a New Calcium(II) Complex with Pyridine-2,6-DiCarboxylate,Water and Nitrate Ligands

Crystals of {catena-[μ-aqua-O]bis[μ-pyridine-2,6-dicarboxylato-O,N-O']} {[monoaqua-nitrato, O-calcium(II)] [diaqua-calcium(II)]} contain dimeric units composed of two calcium(II) ions and two ligand molecules, in which the calcium ions are bridged by two bidentate oxygen atoms, each donated by one carboxylic group of the ligand. The Ca(II) ion is also coordinated by one oxygen atom of the second carboxylate group and the hetero-ring nitrogen atom belonging to the same ligand molecule. The dimers form molecular chains through protons situated at the symmetry centers halfway between the non-bridging carboxylate oxygen atoms. In addition, both calcium ions in the dimer are bridged to calcium ions in adjacent dimers - each by a pair water oxygen molecules giving rise to two-dimensional molecular sheets. Coordination of the Ca ion in the dimer is completed either by two water oxygen atoms or by one water oxygen atom and an oxygen atom donated by a nitrate group. The molecular sheets are held together by an extended system of hydrogen bonds.     

Heteronuclear M(II)-Ln(III) (M = Co, Mn; Ln = La, Pr, Sm, Gd, Dy and Er) coordination polymers: Synthesis, structures and magnetic properties

Thirteen novel 3d-4f heteronuclear coordination polymers based on the pyridine-2,6-dicarboxylic acid (H₂pda) and imidazole ligands, HIm[(pda)₃MLn(Im)₂(H₂O)₂]·3H₂O (Im = imidazole; M = Co, Ln = Pr (1), Gd (2), Dy (3), Er (4); M = Mn, Ln = Pr (5), Sm (6), Gd (7), Dy (8), Er (9)), HIm[(pda)₃CoSm(Im)₂(H₂O)₂]·2H₂O (10), [(Im)₄M(H₂O)₂][(pda)₄La₂(H₂O)₂]·2H₂O (M = Co (11), Mn (12)), and [(pda)₆Co₃Pr₂(H₂O)₆]·6H₂O (13), have been prepared and structurally characterized. X-ray crystallographic analyses revealed that these complexes display four different types of structures. Complexes 1-9 are isostructural, and possess 1-D chain structures constructed by alternately arrayed nine-coordinated Ln(III) (Ln = Pr, Sm, Gd, Dy, Er) and six-coordinated M(II) (M = Mn, Co) ions. Complex 10 exhibits a unique one-dimensional structure, in which two independent chains are parallel viewed down the a-axis and anti-parallel viewed down the c-axis. Complexes 11 and 12 are isostructural and display 1-D homometallic chain structures. Complex 13 is a 3D framework fabricated through PrN₃O₆ and CoO₆ polyhedrons as building blocks. The variable-temperature solid-state dc magnetic susceptibilities of complexes 2, 3, 4, 9 and 13 have been investigated. Antiferromagnetic exchange interactions were determined for these five complexes.     

Synthesis,characterization and crystal structure of a novel three-dimensional supramolecular architecture formed by manganese(II) and pyridine-2,5-dicarboxylic acid

A novel three-dimensional supramolecular compound formed by Mn(II) and pyridine-2,5-dicarboxylic acid of formula [Mn(Pydc)₂(H₂O)₂] (Pydc?=?pyridine-2,5-dicarboxylic acid) has been synthesized and characterized by elemental analyses, IR, electronic spectra, thermogravimetric analysis and X-ray diffraction techniques. The X-ray structure shows that the central Mn(II) ion is coordinated by two water molecules and two chelated Pydc ligands. Water molecules coordinate with Mn(II) ions in the cis mode. Intermolecular hydrogen bonds play an important role in stabilization of the lattice and construction of the supramolecular network.     

Chemoselectivity of 6-bromo-2-methyl-3,1-benzoxazin-4-one towards amines,Schiff bases,and azines

Summary 6-Bromo-2-methyl-3,1-benzoxazin-4-one (1) undergoes an unusual cleavage at position 4 when it is allowed to react witho-phenylenediamine or anthranilic acid in dry benzene to give the corresponding compounds2–5, respectively. The reaction of1 withSchiffbases and azines results in the formation of the compounds6a–d and8a,b, respectively. The reaction involves a cleavage of theSchiff base or the azine into its amine and arylidene moieties which are smoothly incorporated into1 via nucleophilic attack of the amine at position 4 and condensation of the aldehyde with a reactive methyl group, at position 2 respectively. No displacement of the arylidene segment was observed.

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Zur Chemoselektivität von 6-Brom-2-methyl-3,1-benzoxazin-4-on gegenüber Aminen,Schiffschen Basen und Azinen

Zusammenfassung 6-Brom-2-methyl-3,1-benzoxazin-4-on reagiert mito-Phenylendiamin oder Anthranilsäure in trockenem Benzol unter einer ungewöhnlichen Bindungstrennung zu den Verbindungen2–5. Die Reaktion von1 mitSchiffschen Basen und Azinen führt zu den Verbindungen6a–d und8a,b. Die Reaktion verläuft über eine Spaltung derSchiffschen Base oder des Azins in ihre Amin- und Arylidenreste, die über einen nucleophilen Angriff des Amins an Position 4 und Kondensation des Aldehyds mit der reaktiven Methylgruppe in Position 2 glatt in1 übergeführt werden. Es wurde kein Arylidenaustausch beobachtet.

     

Synthesis,crystal structure,sensitivity, and effect on thermal decomposition of ammonium perchlorate: an energetic compound Cu(HATZ)(PDA)(H2O)

An energetic coordination compound, Cu(HATZ)(PDA)(H₂O) (HATZ?=?5-aminotetrazole, H₂PDA?=?pyridine-2,6-dicarboxylic acid), has been synthesized and structurally characterized by single crystal X-ray diffraction. Copper(II) was coordinated by two oxygen atoms and nitrogen from PDA, one ring nitrogen of ATZ and one water to form a five-coordinate, distorted square-pyramidal structure. 3-D supramolecular architecture was formed by hydrogen bonding. Thermal decomposition of the compound was examined by DSC and TG-DTG analyses. The kinetic parameters of the first exothermic process of the compound were studied by Kissinger's and Ozawa–Doyle's methods. Sensitivity tests revealed that the compound was insensitive to mechanical stimuli. In addition, the compound was explored as additive to promote thermal decomposition of ammonium perchlorate by differential scanning calorimetry.     

New approach to the synthesis of substituted 5-arylcarbamoyl-3-cyano-6-methylpyridine-2(1h)-thiones. Molecular and crystal structure of 2-allylthio-3-cyano-5-(2-methoxyphenylcarbamoyl)-6-methyl-4-(5-methyl-2-furyl)-1,4-dihydropyridine

Morpholinium 5-arylcarbamoyl-3-cyano-6-methyl-4-(5-methyl-2-furyl)-1,4-dihydropyridine-2-thiolates have been obtained by the interaction of enamines of acetoacetanilides with 5-methyl-2-furfurylidenecyanothioacetamide. Alkylation of the salts gives thioethers and oxidation gives the corresponding substituted pyridine-2(1H)-thiones. The structure of 2-allylthio-3-cyano-5-(2-methoxyphenylcarbamoyl)-6-methyl-4-(5-methyl-2-furyl)-1,4-dihydropyridine was studied by X-ray crystallographic analysis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 51–58, January, 2006.     

Synthesis and study of the structure of new 3d-metal coordination compounds with substituted 2-amino-4(5H)-ketothiophens

A series of new 3d-metal complexes based on 2-amino-3-(1-methylbenzimidazol-2-yl)-4(5H)-ketothiophen (HL¹) and 2-amino-3-(2-benzothiazolyl)-4(5H)-ketothiophen (HL²) were synthesized. Compounds of the general formulas [ML₂] and [M(HL¹)₂Cl₂] (where M = Co²⁺, Ni²⁺, Zn²⁺, Cu²⁺) were prepared by the reaction of the above mentioned ligands with the corresponding acetate (for [ML₂]) or chloride (for [M(HL¹)₂Cl₂]) salts in a methanol or a methanol–chloroform medium. The choice of the anion in the initial metal salt, as well as the selection of the ligand, is crucial for obtaining coordination compounds with a neutral or deprotonated form of the 2-amino-4(5H)-ketothiophens. Thus, in contrast to HL¹, complexes with the neutral form of HL² cannot be obtained under the same conditions. All the complexes were studied by spectroscopic methods and X-ray crystallography (for [CuL¹₂] · H₂O). The coordination polyhedron of the copper atom is formed by four nitrogen atoms from two ligand anions and the geometry of the coordination sphere is intermediate between tetrahedral and square-planar.     

Three new pyridine-2,6-dicarboxylate copper(II) compounds with coordinated pyridine-based ligands: Synthesis, characterisation and crystal structures

Three new Cu(II) compounds of pyridine-2,6-dicarboxylic acid (H₂pdc) with meta-substituted pyridines as additional ligands have been synthesized and structurally characterised using X-ray diffraction. Two of them are mononuclear compounds, i.e. [Cu(pdc)(3acpyr)(H₂O)] (1) (3acpyr = 3-acetylpyridine) and [Cu(pdc)(3HOp)(H₂O)](H₂O)₂ (2) (3HOp = 3-hydroxypyridine). The third compound is polynuclear, i.e. [Cu(pdc)(μ-3HOmp-κN,O)]_n (3) (3HOmp = 3-(hydroxymethyl)pyridine). The three compounds are also characterised by IR, EPR and ligand field spectroscopy. The geometry around the Cu(II) ions is distorted square pyramidal for compounds 1 and 2 and distorted octahedral for compound 3. The lattice of compound 1 is organised by an intra-sheet hydrogen-bond pattern generating double layers. Compound 2 has a lattice arranged by the two water molecules in the lattice with complicated 2D O-H?O intra-sheet hydrogen bonding motifs.The zig-zag chains in compound 3 are further organised in layers, due to the axial coordination at Cu(II), forming a so-called (4, 3) ladder-like one-dimensional coordination polymer. These ladders are interconnected by hydrogen bonding.     

4-(7-甲氧基-2,2-二甲基-2,3-二氢苯并呋喃-5-基)-2-芳氨基噻唑的合成、晶体结构与杀虫活性

以2-(2-甲基烯丙氧基)苯酚为原料, 经Claisen重排、呋喃环化、醚化、Friedel-Crafts乙酰化、α-溴代和噻唑环化等反应合成了22种4-(7-甲氧基-2,2-二甲基-2,3-二氢苯并呋喃-5-基)-2-芳氨基噻唑化合物. 化合物的结构经质谱、1H NMR和元素分析等确证. 采用单晶X射线衍射仪测定了化合物7j的晶体结构, 该晶体属于单斜晶系, 空间群为C2/c, 晶胞参数a=2.21140(12) nm, b=0.87602(5) nm, c=2.13911(12) nm, β=115.5380(10)°; V=3.7391(4) nm3, Z=8, Dc=1.375 g/cm3, F(000)=1616, S=1.046, μ=0.333 mm-1, 最终偏差因子R1=0.0390, wR2=0.1079. 杀虫活性实验结果表明, 化合物7a, 7b, 7h和7t在浓度为500 mg/L时对蚕豆蚜死亡率分别为95.12%, 62.60%, 57.53%和59.06%.     

Fe(III)与两种4-羟基吡啶二酸形成的配合物的合成与晶体结构

A iron(III) complex [Fe(2,6-HDA)(2,5-HDA)(H₂O)₂]·2.5H₂O (2,6-HDA=4-hydroxypyridine-2,6-dicarboxylic acid, 2,5-HAD=4-hydroxypyridine-2,5-dicarboxylic acid), has been hydrothermally synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. It belongs to monoclinic system, with space group C2/c, a=0.155 8(4) nm, b=0.215 8(5) nm, c=0.133 0(3) nm, β=125.468(3)°, V=3.641 1(15) nm³, Z=8. The geometry around iron(III) is a distorted pentagonal bipyramid. CCDC: 631130.     

5-苄基-4-叔丁基-2-芳氨基噻唑氢溴酸盐的合成、表征及抗肿瘤活性

以芳香胺和4,4-二甲基-1-芳基-2-溴戊-3-酮为原料, 设计合成了29种新的5-苄基-4-叔丁基-2-芳氨基噻唑氢溴酸盐化合物; 其结构经¹H NMR和元素分析等确证. 体外抗肿瘤活性测试结果表明, 化合物A4, A5, A12和A29对人非小细胞肺癌细胞A549的IC₅₀值分别为0.016, 0.019, 0.019和0.026 μmol/mL, 与阳性对照物紫杉醇(IC₅₀值为0.022 μmol/mL)相当; 化合物A5, A7, A13, A14和A19对肝癌细胞Bel7402的IC₅₀值分别为0.021, 0.021, 0.026, 0.014和0.029 μmol/mL, 与阳性对照物紫杉醇的IC₅₀值(0.030 μmol/mL)相近. 利用倒置显微镜和Hoechst33342-PI双染色法观察了细胞经化合物处理后的形态变化.     

4-甲基-3-硝基苯甲腈和2-甲基-5-硝基苯甲腈的合成与表征

4-甲基-3-硝基苯甲腈和2-甲基-5-硝基苯甲腈是重要的有机合成中间体[1,2],因其芳环上具有硝基和氰基两个第二类取代基,同时又有一个可参与反应的甲基而使得这两个化合物在有机合成领域有着广泛的应用前景.芳环上的甲基可以氧化为酸,也可进一步反应形成酰氯、酯等功能基;芳环上的氰基可水解成羧基,也可以与叠氮钠在Lewis酸催化下形成具有生物活性的四唑衍生物;芳环上的硝基经还原可形成氨基,如4-甲基-3-硝基苯甲腈通过化学反应可环合形成药物中间体6-氰基吲哚[2～4].     

Synthesis of 5-[2-(Phenoxy)ethyl] Derivatives of 6-Methyluracil, 6-Methyl-2-thioxo-2,3-dihydro-1H-pyrimidin-4-one,and 2-Imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one

A synthesis of novel derivatives of 6-methyluracil, 6-methyl-2-thioxo-, and 2-imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one containing a 2-(phenoxy)ethyl substituent at position 5 of the pyrimidine ring has been carried out. It was found that 5-[2-(phenoxy)ethyl] derivatives of 6-methyl-2-thioxo- and 2-imino-6-methyl-2,3-dihydro-1H-pyrimidin-4-one are obtained by the condensation of the corresponding ethyl 3-oxo-2-(2-phenoxyethyl)butanoates with thiourea or guanidine. 6-Methyl-5-[2-(phenoxy)ethyl]uracils can be prepared by treating 6-methyl-5-[2-(phenoxy)ethyl]-2-thioxo-2,3-dihydro-1H-pyrimidin-4-ones with an excess of aqueous monochloroacetic acid solution. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1213–1217, August, 2005.     

Copper(II) complexes of N(4)-substituted thiosemicarbazones derived from pyridine-2-carbaldehyde: Crystal structure of a binuclear complex

Ten copper(II) complexes {[CuL¹Cl] (1), [CuL¹NO₃]₂ (2), [CuL¹N₃]₂ · 2/3H₂O (3), [CuL¹]₂(ClO₄)₂ · 2H₂O (4), [CuL²Cl]₂ (5), [CuL²N₃] (6), [Cu(HL²)SO₄]₂ · 4H₂O (7), [Cu(HL²)₂] (ClO₄)₂ · 1/2EtOH (8), [CuL³Cl]₂ (9), [CuL³NCS] · 1/2H₂O (10)} of three NNS donor thiosemicarbazone ligands {pyridine-2-carbaldehyde-N(4)-p-methoxyphenyl thiosemicarbazone [HL¹], pyridine-2-carbaldehyde-N(4)-2-phenethyl thiosemicarbazone [HL²] and pyridine-2-carbaldehyde N(4)-(methyl), N(4)-(phenyl) thiosemicarbazone [HL³]} were synthesized and physico-chemically characterized. The crystal structure of compound 9 has been determined by X-ray diffraction studies and is found that the dimer consists of two square pyramidal Cu(II) centers linked by two chlorine atoms.