Cl Compound Research Articles

X-ray crystal structure, ESR and potentiometric studies of copper(II) complexes with (2-pyridylmethyl, 3-pyridylmethyl) amine ligand

In this paper, we describe the coordinating behaviour of the (2-pyridylmethyl, 3-pyridylmethyl) amine ligand with the copper(II) ion. This ligand is bidentate and forms, in accordance with the pH values, 1:1 and 1:2 species (ratio metal:ligand). These species were characterized in aqueous solution by ESR spectroscopy and their overall stability constants were determined by potentiometric measurements. In solid state, we obtained the compounds [CuLHCl2](BF4) and [CuL2](BF4)2. In ESR spectroscopy, the first compound is characterized by an axial g tensor (g∥=2.268 and g⊥=2.091), whereas the second one is characterized by a rhombic g tensor (g1=2.185, g2=2.146 and g3=2.026). We crystallized the [CuLHCl2]Cl compound, in hydrochloric medium, from the [CuLHCl2](BF4) powder. The compound obtained is a pseudo octahedral dimeric system, in which each copper(II) is surrounded by two nitrogen atoms and four chloride ions. The intramolecular Cu–Cu distance is 3.859 Å.

Development of a flow injection chemiluminescent assay for the quantification of lipid hydroperoxides

AbstractAn automated flow injection chemiluminescence (FICL) system for measuring lipid hydroperoxide (LOOH) concentrations in oils was developed. Initially, a crude oil‐in‐water emulsion (formed by mixing solvent‐diluted oil with the aqueous‐based CL compound, luminol, and the catalyst for the reaction, cytochrome c) was tested. The assay was rapid (60 samples per hour), reproducible (CV no greater than 10%, n=3) and had a low sample requirement (1 mg of oil) because of its high sensitivity (0.5 nmol LOOH). CL intensity was influenced by the amount and type of oil under analysis. Owing to these factors, quantitative data were attainable only with a uniform oil concentration and with a calibrant derived from an oil equivalent to that under analysis. This method yielded quantitative data in good agreement with an iodometric titration assay for LOOH (r=0.9204). A refinement of the first method consisted of replacing the luminol and cytochrome c CL compounds with lucigenin, resulting in an assay insensitive to α‐tocopherol. A monophasic reaction solution was devised to remove the effect of turbidity; however, the CL signal was still influenced by oil type. Therefore, quantitative data were still attainable only when the same type of oil was used for calibration.

Octachloroazulene.

The title compound, the first perhaloazulene, has been synthesized from hexachlorobutadiene and cyclopentadiene. Further chlorination of 1,3,4,5,6,7-hexachloroazulene results in addition, not substitution, under electrophilic as well as free radical conditions. Radical chlorination of the hexachloroazulene affords in good yield a single decachlorotetrahydroazulene. Treatment of this Cl(10) compound with one equiv of a phosphazene base gives a nonachlorodihydroazulene, but the addition of a second equiv results in dechlorination to 1,2,3,4,5,6,7-heptachloroazulene as well as dehydrochlorination to octachloroazulene. The former azulene is obtained cleanly from the Cl(9) compound with acid catalysis or by reduction with mercury. In the presence of calcium carbonate, however, the Cl(9) intermediate yields the dark green octachloroazulene. Although octachloronaphthalene is readily converted into its octafluoro counterpart, the isomeric octachloroazulene is far too sensitive to undergo the analogous transformation.

NMR studies on a palladium(II) complex containing an incompletely coordinated facultative pentadentate Schiff base ligand

AbstractPalladium(II) dichloride reacts with 1,10‐bis(2‐pyrrolyl)‐2,5,9‐triaza‐1,9‐decadiene to give a [Pd(C15H20N5)]Cl complex in which the ligand is four‐coordinated, leaving one pyrrole group dangling. By using COSY, gHSQC, gHMBC connectivities and NOE experiments it has been concluded that one linkage isomer exists in DMSO solution, in spite of the fact that different sets of N atoms of potentially pentadentate ligand might be involved in coordination, and that the three chelate rings in the complex cation are arranged in a sequence: five‐membered, six‐membered, five‐membered which is different from that (5–5–6) found by x‐ray studies on the related [Ni(C15H20N5)]Cl compound. NMR studies allowed an unambiguous assignment of all 1H and 13C NMR resonances for the complex. Results of x‐ray structural analysis of [Pd(C15H20N5)](CH3COO)H2O supported the five‐membered, six‐membered, five‐membered ring sequence in the [Pd(C15H20N5)]+ complex cation and show an E (trans) orientation of the dangling pyrrole group with respect to the metal center. Copyright © 2002 John Wiley & Sons, Ltd.

Synthesis and characterization of a novel cyclic aluminophosphinate: structure and solid-state NMR study.

We present the structure and a multinuclear solid-state NMR study of a new cyclic aluminophosphinate. The crystallographic structure of [Al(2)(HC(6)H(5)PO(2))(2)(C(4)H(9)OH)(8)]Cl(4) (compound 1) was obtained at low temperature (a = 11.830(7) A, b = 14.216(6) A, c = 17.790(6) A, beta = 91.25(4) degrees, monoclinic, P21/c, Z = 2). (13)C IRCP (inversion recovery cross polarization) and NQS (non quaternary suppression) NMR experiments allowed the complete assignment of the quaternary carbon atom of the phenyl ring and the precise determination of the isotropic /(1)J(P-C)/ coupling constant. (31)P CP MAS dynamics was carefully studied by varying the contact time. Dipolar oscillations even at slow MAS were observed. Up to 11 kHz, these oscillations were more pronounced, and the P-H distance was easily extracted. (27)Al NMR quadrupolar parameters for 1 were obtained with very good accuracy, and unusual satellite transition splitting was observed. Furthermore, the isotropic lines of the inner and outer transitions were clearly observable, leading to the unambiguous determination of the quadrupolar parameters.

Electron Paramagnetic Resonance in the Singlet Dimer System (CH3)2CHNH3CuBr3

Electron paramagnetic resonance measurements were performed at 24 GHz on the magnetic compound (CH 3 ) 2 CHNH 3 CuBr 3 , which consists of antiferromagnetic-antiferromagnetic alternating Heisenberg chains. The results are compared with those obtained for ferromagnetic-antiferromagnetic chains (CH 3 ) 2 CHNH 3 CuCl 3 reported in Phys. Rev. B 62 (2000) 14279. The absorption intensity, after showing a broad maximum around 70 K, decreases to zero when the temperature approaches 0 K. Contrary to the case in the Cl compound in which the absorption line splits into two lines around 10 K, a single absorption line persists down to 1.4 K, the lowest temperature of these experiments. These results are interpreted to result from formation of singlet dimers at low temperatures. The Dzyaloshinsky-Moriya exchange interaction is strongly suggested to be the main perturbation term from the analysis of the dependence of linewidth and resonance field on temperature.

The Effect of Coal Combustion Flue Gas Components on Low-Level Chlorine Speciation Using EPA Method 26A

ABSTRACT U.S. Environmental Protection Agency (EPA) Method 26A is the recommended procedure for capturing and speci-ating halogen (X2) and hydrogen halide (HX) stack emissions from combustion sources. Previous evaluation studies of Method 26A have focused primarily on hydrogen chloride (HCl) speciation. Capture efficiency, bias, and the potential interference of Cl2 at high levels (>20 ppm [u,g/m3]) and NH4Cl in the flue gas stream have been investigated. It has been suggested that precise Cl2 measurement and accuracy in quantifying HX or X2 using Method 26A are difficult to achieve at Cl2 concentrations <5 ppm; however, no performance data exist to support this. Coal contains low levels of Cl, in the range of 5-2000 ppmw, which results in the presence of HCl and Cl2 in the products of combustion. HCl is the predominant Cl compound formed in the high-temperature combustion process, and it persists in the gas as the products of combustion cool. Concentrations of Cl2 in coal combustion flue gas at stack temperatures typically do not exceed 5 ppm. For this research, bench-scale experiments using simulated combustion flue gas were designed to validate the ability of Method 26A to speci-ate low levels of Cl2 accurately. This paper presents the results of the bench-scale tests. The effect of various flue gas components is discussed. The results indicate that SO2 is the only component in coal combustion flue gas that has an appreciable effect on Cl2 distribution in Method 26A impingers, and that Method 26A cannot accurately speciate HCl and Cl2 in coal combustion flue gas without modification.

Formation of Alternating Antiferromagnetic Heisenberg Chains in (CH3)2CHNH3CuBr3

We report that antiferromagnetic and antiferromagnetic (AF-AF) alternating Heisenberg chains with S =1/2 are formed in (CH 3 ) 2 CHNH 3 CuBr 3 , which is in contrast to the almost isomorphous compound (CH 3 ) 2 CHNH 3 CuCl 3 , because the Cl compound forms ferromagnetic-dominant ferromagnetic and antiferromagnetic (F-AF) alternating Heisenberg chains [H. Manaka et al. : J. Phys. Soc. Jpn. 66 (1997) 564]. From the analysis of the dependence of magnetic susceptibility on temperature, χ( T ), the two different antiferromagnetic exchange interactions defined in the Hamiltonian H = -2 J 1 ∑ S 2 i · S 2 i +1 -2 J 2 ∑ S 2 i · S 2 i -1 are determined to be J 1 / k =-61 K and J 2 / k =-33 K. Applying the low temperature experimental data to the formula χ( T )∝ T -1/2 exp (-Δ/ k T ), we estimate the energy gap Δ to be 98 K. We discuss why AF-AF and F-AF alternating chains are formed in the Br and the Cl compounds, respectively, in spite of their almost isomorphous crystal structures.

Hall effect and magnetic viscosity phenomena in κ-(BEDT-TTF)2Cu[N(CN)2]X (X=Cl, Br)

Hall effect studies have been performed in the compounds \ensuremath{\kappa}-(BEDT-TTF${)}_{2}$Cu[N(CN${)}_{2}$]X, where X=Cl and Br and BEDT-TTF is bis(ethylenedithio)tetrathiafulvalene, in the temperature range 100 to 10 K. Hall constant has been found to be temperature independent in the Br salt down to 55 K and equal to +2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$ ${\mathrm{m}}^{3}$/C. In the Cl salt the Hall constant is equal to +1.4\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}7}$ ${\mathrm{m}}^{3}$/C at 100 K and increases on cooling down to 70 K almost parallel to the resistance increase. Below \ensuremath{\sim}70 and \ensuremath{\sim}55 K in the Cl and Br, respectively, the magnetic field change has been found to produce long-term sample resistance relaxation. The relaxation phenomena change dramatically with temperature, reaching the maximum above magnetic ordering temperature in the Cl salt at 30 K, and then sharply dropping in magnitude in the magnetically ordered state. A similar relaxation is observed in the Br salt. These effects are considered to be due to the magnetic domain structure formation in the antiferromagnetically ordered state. Essential changes of the domain wall dynamics, appearing in the Br salt at 25 K, evidence the presence of the second magnetic transition in the Br salt, quite similar to the Cl salt. By studying the anisotropy of the relaxation phenomena within highly conducting plane in the Cl compound it is shown that domain walls are lying parallel to the a direction. A possible origin of the magnetic order in the salts is discussed.

Metal pyrazolate polymers. Part 3. Synthesis and study of Cu(I) and Cu(II) complexes of 4-Xdmpz (where X = H, Cl, Br, I, and CH3 for Cu(I) and X = H, Cl, Br, and CH3 for Cu(II); dmpz = 3,5-dimethylpyrazolate)

The copper(I) complexes [Cu(4-Xdmpz)]3 (where X = H, Cl, Br, I and CH3; dmpz = 3,5-dimethylpyrazolate) and the copper(II) complexes [Cu(4-Xdmpz)2]x have been synthesized and characterized. Qualitative solubility, infrared spectroscopic, and differential scanning calorimetric studies are reported for all complexes. Mass spectra support trimeric formulations for the copper(I) complexes. Scanning electron micrographs and powder X-ray diffractograms have been recorded for the copper(II) compounds. Electronic and EPR spectroscopic studies as well as magnetic susceptibility studies from 2 to 300 K are also reported for the copper(II) compounds, which are proposed to have polymeric chain structures. The magnetic data reveal strong antiferromagnetic interactions in all four of the copper(II) compounds. The data have been analysed employing an isotropic Heisenberg model for antiferromagnetic coupling in extended chain polymers. Values of the exchange coupling constant, J, are determined as −58, −61, −66, and −66 cm−1 for the X = H, CH3, Cl, and Br complexes respectively. The X = Cl compound exhibits an abrupt decrease in magnetic susceptibility below 40 K and possible causes of this anomalous behaviour are discussed.

Metal pyrazolate polymers. Part 2. Synthesis, structure, and magnetic properties of [Cu(4-Xpz)2]x polymers (where X = Cl, Br, Me, H; pz = pyrazolate)

Novel and reliable methods for the synthesis of the polymers [Cu(4-Xpz)2]x (where X = H, Cl, Br, and Me; pz = pyrazolate) are presented. The X = Cl compound was obtained as green and brown forms. Single crystals of the polymers with X = Me and X = Cl (green form) suitable for X-ray analysis have been obtained. [Cu(4-Mepz)2]x and [Cu(4-Clpz)2]x are isomorphous, crystallizing with four formula units per unit-cell in the orthorhombic space group Ibam, a = 9.7436(6), 9.155(4), b = 12.6106(8), 12.968(6), and c = 7.7482(6), 7.717(5) Å, respectively, for the 4-Me and 4-Cl derivatives. The structures were refined by full-matrix least-squares procedures to R = 0.027 and 0.041 for 430 and 246 reflections with I ≥ 3σ(I), respectively. Magnetic susceptibility studies over the temperature range 2 to 300 K have revealed that all the polymers exhibit very strong antiferromagnetic exchange between copper(II) centres in the extended linear chains. Discontinuities displayed in the susceptibility versus temperature plots suggest the presence of phase transitions at ~133 and ~108 K in the X = Cl (green form) and X = Br materials, respectively. The four compounds, X = H, Br, Me, and Cl (green form) also exhibit thermochromism over the 77 to 176 K region. The magnetic data have been analyzed employing an isotropic Heisenberg model for antiferromagnetic exchange in extended chain polymers. Values of the exchange coupling constant, J, for the room temperature forms of these materials are determined as −81, −105, −96, −104, and −88 cm−1 for 4-X = H, Br, Me, Cl (green form), and Cl (brown form), respectively. The magnitude of the exchange coupling is discussed in relation to structural parameters for the X = H, Me, and Cl (green form) compounds. Key words: copper(II) 4-substituted pyrazolate polymers, crystal structures, magnetic exchange.

発光化合物を用いるか粒球，マクロファージの酸化種生成能の測定法

Chemicals emitting light in visible region, when they are oxidized at physiological pH, have been used for testing the generation of active oxygen species and related oxidants. Of these chemicals, luminol has been widely used for testing the function of phagocytizing monocytes and granulocytes. Luminol is known to be oxidized to aminophthalic dianion which in turn emits a light with maximum at 425 nm in aqueous media. The various oxidants generated during phagoctizing, such as O-2, -O Cl and myeloperoxidase compound III, are involved in luminol dependent luminescences.Lucigenin, also a chemiluminescence compound, emits a light in visible region during phagocytizing, but produce much move weaker light compared with luminol in phagocytizing granulocytes. Lucigenin-dependent luminescence, however, participates in the generation of O-2 (probably also H2O2) but not in the myeloperoxidase-mediated reactions.Very sensitive and specific method for testing an ability of O- generation in phagocitizing granulocytes and macrophages is considered to be a chemilunescence probe with a crypridina luciferin analog. The compound is, in the main, oxidized to an excited carbonyl in singlet state by O-, but not by H2O2. Under specified conditions, O generating ability of macrophages and granulocytes can be calculated and expressed as xanthine oxidase units.

Copper(II) halide complexes of 2-aminobenzophenone. Crystal and molecular structure of bis(2-aminobenzophenone)dichlorocopper(II)

The complexes CuX 2L 2 (X = Cl, Br; L = 2-aminobenzophenone) were prepared and characterized by means of magnetic and spectroscopic measurements. For the Cl compound the crystal structure was also determined. Crystals are triclinic, space group P 1 , with a = 13.397(3), b = 10.752(2), c = 9.205(2) Å, α = 72.26(1)°, β = 91.58(1)°, γ = 106.86(1)°, and Z = 2. The structure was solved by the heavy-atom method and refined by least-squares calculations to R = 0.034 for 2581 counter data. It consists of discrete CuX 2L 2 monomers showing distorted trigonal bipyramidal coordination geometry about the copper ion. The amino nitrogens are axial ligands, with the equatorial positions occupied by two chlorine atoms and a carbonyl oxygen from one L molecule acting as a bidentate ligand. Infrared and ligand field spectroscopies and magnetic measurements, interpreted on the basis of the known crystal structure, also suggest a similar structure for the related Br compound.

Synthesis and reactivity of some p-mesityl-substituted phosphorus compounds

Abstract : The preparation and characterization of a series of P-mesityl substituted phosphorus compounds containing the Si-N-P and/or Si-C-P linkages are described. The reaction of RPC12 (R = 2,4,60Me3C6H2) with one equivalent of (Me3Si)2NLi affords the thermally unstable chlorophosphine (Me3Si)2NP(R)Cl (compound 1) in nearly quantitative yield. Substitution reactions of compound 1 are used to prepare the stable derivatives (Me3Si)2NP(R)X (compound 2, X = Me; compound 3, X = H; compound 4, X = CH2SiMe3), while treatment with Me3SiN3 yields the unstable axidophosphine (Me3Si)2NP(R)N3 (compound 5). The methylphosphine compound reacts smoothly with CC14 via elimination of CHCl3 with a (1,3)-silyl shift to form the chlorophosphinimine Me3SiN=P(R) (CH2SiMe3)Cl (compound 6), which is readily converted to the P-Me analogue compound 7 by reaction with MeLi. Depending on the reaction stoichiometry, treatment of RPCl2 with Me3SiCH2MgCl gives either the chlorophosphine Me3SiCH2P(R)Cl (compound 8) as an unstable product from which compound 4 is produced by reaction with (Me3Si)2NLi, or the stable disubstituted phosphine (Me3SiCH2)2PR (compound 9). Decomposition of the azidophosphine compound 5 proceeds with elimination of nitrogen and formation of the dimeric forms of the di(imino)phosphorane RP double bond(NSiMe3)2 (compound 5 a). Either the cis (compound 10) or trans (compound 11) four-membered ring dimer can be isolated under appropriate conditions. Proton, C(13), P(31) NMR data are reported for the new compounds. (Author)

Raman spectroscopy study of powdered [Ni(NH3)6] X2 compounds

AbstractTen out of eleven Raman active modes were detected in [Ni(NH3)6] X2 powders, apart from internal modes of the X− ions. The Raman active lattice mode happens to agree fairly well with the predictions of a model based on the electrostatic potential field of point charges. The X = Cl compound showed evidence of losing ammonia during irradiation with the laser beam. Two modes (the NNiN angle deformation and the lattice vibration) are especially sensitive to the NH3− vacancies thus created.