摘要:

The iron(II) complexes Fe(NC5H5)4(RSO3)2where R = CF3, CH3, andp-CH3C6H4have been prepared and their crystal structures determined by single crystal X-ray diffraction. Crystals oftrans-bis(methanesulfonato-O)tetrakis(pyridine)iron(II) are monoclinic,a = 16.524(2),b = 9.1127(6),c = 18.684(2) Å, β = 109.903(6)°,Z = 4, space groupPn. The structure was solved by conventional heavy-atom methods and was refined by full-matrix least-squares procedures toR = 0.034 andRw = 0.038 for 4243 reflections withI ≥ 3α(I). Crystals oftrans-bis(trifluoromethanesulfonato-O)tetrakis(pyridine)iron(II) are monoclinic,a = 10.456(1),b = 9.2981(8),c = 14.625(2) Å, β = 96.372(6)°,Z = 2, space groupPn. Structure solved and refined as above toR = 0.036, andRw = 0.037 for 1483 reflections withI ≥ 3σ(I). Crystals oftrans-bis(p-toluenesulfonato-O)tetrakis(pyridine)iron(II)are orthorhombic,a = 40.818(2),b = 9.8722(6),c = 17.3544(7) Å,Z = 8, space groupFdd2. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures toR = 0.030 andRw = 0.032 for 1851 reflections withI ≥ 3σ(I). All three structures show discrete octahedral molecules with monodentatetrans-coordinated sulfonate groups. Two crystallographically independent molecules are observed in the R = CH3structure, the difference between them involving the orientation of the CH3SO3groups with respect to the O—Fe—O vector. The FeN4O2chromophore in each compound is a tetragonally compressed octahedron (approximateD4h, symmetry) with average Fe—N distances of 2.21, 2.23, and 2.24 Å and Fe—O distances of 2.11, 2.06, and 2.08 Å for theCF3, CH3, andp-CH3C6H4derivatives, respectively. The compounds were studied using vibrational, electronic, and Mössbauer spectroscopic methods, magnetic susceptibility measurements, and differential scanning calorimetry. Quadrupole splitting values from Mössbauer spectra indicate a5B2gground state for all three compounds and magnetic susceptibility data (310–4.2 K) have been analyzed assuming this ground state, using both a crystal field and a zero-field splitting model.

ISSN:0008-4042    

DOI:10.1139/v86-068

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

A number of methylmercurated complexes of 6-mercaptopurine riboside and 2-amino-6-mercaptopurine riboside (6-MNucH2) containing S-bound CH3Hg(II) in neutral and cationic complexes (as in [CH3Hg(6-MNucH)] and [CH3Hg(6-MNucH2)]NO3), S- and N-bound CH3Hg(II) (as in [(CH3Hg)2(6-MNucH)]NO3), and S-, N-, C-bound CH3Hg(II) (as in [(CH3Hg)3(6-MNuc)]NO3) have been prepared in aqueous solution at appropriate pH and mole ratios of the constituents. The complexes were characterized by means of1H and13C nmr and ir spectroscopy and elemental analysis. Formation of C-bound methylmercurated species extends our previous results obtained with xanthosine, inosine, and imidazole derivatives, and substantiates our proposal that activation through electrophilic coordination at N(7) is a requirement for C(8)—H abstraction.2J(1H–199Hg) coupling constants, measured in (CD3)2SO for a number of CH3Hg(II) complexes of N-, S-, and C-donor heterocyclic ligands, including the 6-mercaptopurine riboside of the present study, correlate well with the1J(13C–199Hg) coupling constants, according to1J = 8.4602J − 155.6. The significance of this correlation in terms of the strength of the Hg–ligand bond is considered. The results could provide insight into the apparent selectivity of binding of CH3Hg(II) by bio-ligands, as well as in the design of chemotherapeutic agents for the treatment of methylmercury poisoning.

ISSN:0008-4042    

DOI:10.1139/v86-069

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Two synthetic approaches for the synthesis ofN,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) and derivatives are reported. The first involves conversion ofN,N′-di(2-hydroxybenzyl)ethylenediamine to the diamide HBEDDA via reaction with formaldehyde and HCN followed by hydrolysis. Analysis of the species distribution curves of the Cu(II) chelates ofN,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) and its diamide, HBEDDA, and of the nature of the coordination in each complex species formed, suggest the selection of the reaction conditions most favorable for the Cu(II)-catalyzed hydrolysis of HBEDDA to HBED. The rate of conversion was found to be low, and the reasons for these findings are described. Iron(III) catalysis of the conversion of HBEDDA to HBED was found to be rapid and complete with a pseudo-first-order rate constant of 3.1 × 10−3 s−1at 25.0 °C. The results provide the final step of a new method for the synthesis of HBED. The second synthetic approach involves reaction ofN,N′-ethylenediamine-diacetic acid (EDDA) with substituted phenols and formaldehyde. These approaches appear to be general for the synthesis of HBED and derivatives.

ISSN:0008-4042    

DOI:10.1139/v86-070

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Acetylenic acids are isomerized by alkali metal amides of 1,3-diaminopropane to 3,5-dienoic acids. An acid with a methyl branch at C-3 separating the carboxyl from the triple bond is rearranged to a mixture of the terminal alkynoic acid and two isomeric 3,5-dienoic acids. The corresponding 4-methyl compound affords the terminal alkynoic acid, one 3,5-dienoic acid, and two cyclized products,cis- andtrans-3-methyl-5-(octylidene)-1-cyclopentanecarboxylic acids. Propargylic acids branched at C-5 and C-6 are rearranged to the appropriately substituted 3,5-dienoic acids in moderate yield.

ISSN:0008-4042    

DOI:10.1139/v86-071

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The structure of [Ir2(CO)2(μ-H)(μ-CO)(DPM)2][BF4] (DPM = Ph2PCH2PPh2) has been determined crystallographically. It crystallizes in the monoclinic space groupP21/n(a = 13.7740(6) Å,b = 15.277(2) Å,c = 23.581(2) Å, β = 97.015(5)°,V = 4924.9 Å3,Z = 4) and on the basis of 6628 unique observations and variation of 272 parameters, the structure converged toR = 0.031 andRw = 0.043. This metal–metal bonded complex is similar to its rhodium analogue, having the two essentially identical Ir centres bridged by the carbonyl, hydride, and two diphosphine ligands. The major difference between this compound and the rhodium species (in the solid state) relates to the orientation of the phenyl groups of the diphosphine ligands; in the iridium complex four of these groups block the sites adjacent to the bridging hydride ligand, whereas these sites are relatively unobstructed in the rhodium analogue. This difference may result in different coordination sites for substrate molecules and therefore in different chemistry.

ISSN:0008-4042    

DOI:10.1139/v86-072

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Bonded phases were produced by reacting 2,4,7,9-tetramethyl-5-decyne-4,7-bis(polyethyleneoxide 30 mol) ether (Surfnol® 485) with silicic supports of high and low surface area. There is circumstantial evidence (a) that the nonextractable layer is held by multiple hydrogen bonding and (b) that the synthesis of these packings involves a reaction at the crosslinking site of the surfactant. The bonded phases, with layer thicknesses between 10 and 30 Å, were tested with three chromatographic techniques. In gas–solid chromatography, the phase proved well deactivated and yielded a reduced plate height of 2.5 (using a silica gel support). In gel permeation chromatography, polyethyleneglycols eluted within the mobile-phase volume. In liquid–solid (normal-phase adsorption) chromatography, the elution pattern differed significantly from that of unmodified silica gel. In each case, high-efficiency separations were obtained. The chromatographic experiments thus demonstrated the potential usefulness of the new phase for both gas and liquid chromatography. However, it was not tested in direct comparison with conventional phases nor was its utility established by subjecting it to routine analytical use.

ISSN:0008-4042    

DOI:10.1139/v86-073

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The synthesis and crystal structure of the title complex are reported. Crystals are triclinic, space groupwitha = 10.359(2),b = 10.742(2), andc = 13.604(2) A, α = 87.25(1), β = 88.89(1), γ = 83.63(2)°, andZ = 2. The structure was solved by the heavy atom method and refined by least squares to finalRandRwof 0.055 and 0.06 for 1707 unique reflections. The structure is comprised of planar [Se2(o-phenylenethiourea)6]4+ions and bromide counterions with the water molecules providing extensive lattice stabilization through hydrogen bonding. The dinuclear complex arises by the fusion of two SeS4trapezoids with each Se bonded strongly to two terminal sulfur atoms Se—S(1) = 2.306(4), Se—S(3) = 2.286(5) Å and weakly to two other bridging sulfur atoms Se—S(2) = 2.840(5) and Se—S(2)′ = 2.852(5) Å.

ISSN:0008-4042    

DOI:10.1139/v86-074

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The densities, refractive indices, and viscosities of liquidn-nonadecane andn-nonadecyl benzene were investigated at temperatures not too far above their respective melting points. Except for the viscosities, no significant differences were observed in the behavior of the two hydrocarbons. Then-nonadecane +n-nonadecyl benzene system exhibits small positive excess volumes and small negative excess viscosities. The excess refractive index is zero in the entire concentration range.

ISSN:0008-4042    

DOI:10.1139/v86-075

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The solubility products of phosphate and vanadate apatites of lead and seven of their solid solutions, spread over the entire compositional range, were determined in 0.165 Msodium chloride solution at 37 °C. These solubility products decreased with an increase in vanadium content. A theoretical interpretation was advanced based on changes in lattice and hydration energies resulting from isomorphous ionic substitutions. The aim of the studies was the understanding of the toxic effects of lead and vanadium on the human skeletal system.

ISSN:0008-4042    

DOI:10.1139/v86-076

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The application of fast atom bombardment (FAB) mass spectrometry to the determination of lead isotope ratios in nineteenth century pottery glazes from the Niagara Peninsula has been investigated with the aim of determining the source of the lead used in the glazes. Methods of sampling have been compared, including direct analysis of glass chips, analysis of powdered glaze scrapings, analysis of acid extracts of the former, and simple acid leaching of the surface of a piece of pottery. The latter method gave the best results. The FAB data, as obtained on an older mass spectrometer, can distinguish lead from igneous vs. sedimentary deposits, but is not adequate to determine specific mining locations. Although newer FAB instrumentation can narrow this range, the overlap of data from the Niagara Peninsula and England precludes a simple answer to the archeological question as to English vs. Canadian origin of the lead used in the Jordan pottery glazes. However, the data do suggest that the potter used a local source for the lead.

ISSN:0008-4042    

DOI:10.1139/v86-077

出版商:NRC Research Press    

年代:1986

数据来源: NRC