摘要:

Crystals of tetrakis(4-methylpyridine)cobalt(II) hexafluorophosphate, C24H28CoF12N4P2, are tetragonal, space groupI41/acd,a = 18.434(7),c = 18.818(6) Å,Z = 8. The structure was solved by direct and Fourier methods. The positional and anisotropic thermal parameters were refined by full-matrix least-squares methods toR = 0.072 for 346 observed reflexions. The structure consists of discrete [Co(4-mepy)4]2+and PF6−ions. The structure of the cation is a distorted tetrahedron of 4-methylpyridine ligands around cobalt (crystal symmetryS4) and that of the anion is a distorted octahedron of fluorines around phosphorus (crystal symmetryC2).

ISSN:0008-4042    

DOI:10.1139/v79-022

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The synthesis and coordinating properties of the tridentate tris-chelating ligand, methyl tris(3,5-dimethylpyrazol-1-yl)gallate, MeGa(N2C5H7)3−, are described. Carbonyl and nitrosyl carbonyl compounds of manganese, molybdenum, and tungsten incorporating this ligand are detailed. The ready conversion of the above ligand to the less sterically demanding tris-chelating 'hydroxy' ligand [MeGa(N2C5H7)2(OH)]−occurs in attempted syntheses of the 'η3-allyl' complexes, [MeGa(N2C5H7)3]M(CO)2'η3-allyl', (where M = Mo or W, 'η3-allyl' = η3-C3H5, η3-C4H7). The tridentate chelating nature of this 'hydroxy' ligand is conclusively demonstrated in the crystal structure determination of the complex, [MeGa(N2C5H7)2(OH)]-Mo(CO)2(η3-C4H7). Crystals of this complex are monoclinic,a = 14.020(4),b = 10.110(1),c = 15.493(7) Å, β = 111.58(3)°,Z = 4, space groupP21/n. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures to a finalRof 0.40 andRwof 0.043 for 3374 reflections withI ≥ 3.5σ(I).

ISSN:0008-4042    

DOI:10.1139/v79-023

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Densities and kinematic viscosities of molten mixtures of nickel(II) chloride in tetra-n-butylammonium iodide have been measured as functions of temperature and composition. The data on the kinematic viscosity have been analyzed using both Arrhenius and non-Arrhenius type equations. The heat of activation, the entropy of activation, and the free energy of activation for viscous flow have been computed. At higher concentrations a slight tendency towards non-Arrhenius viscous behaviour is observed. The free energy of activation helps in describing the overall composition dependence of kinematic viscosity.

ISSN:0008-4042    

DOI:10.1139/v79-024

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Data are presented on the heats of phase transitions and electrical conductances of the even chain length manganese(II) carboxylates from octanoate to octadecanoate inclusive. The total entropy change for the transition crystal → isotropic liquid is small indicating a high degree of aggregation in the isotropic liquid. This behaviour is similar to that of the cadmium carboxylates.Plots of log specific conductivity against inverse temperature show curvature. Attempts to fit the data to the Vogel–Tammann–Fulcher equationshowed non-random deviations. Instead, the data were interpreted in terms of a simple dissociation equilibrium for which the enthalpy change is ∼240 kJ mol−1.

ISSN:0008-4042    

DOI:10.1139/v79-025

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

A synthetic intermediate expected to be aspirobenzylisoquinoline bromo-derivative proved, on X-ray crystal structure analysis, to be the title compound, a chloro-derivative with the isoquinoline nitrogen ring-closed. Crystals belong to the monoclinic system, space groupP21/c,a = 13.68(2),b = 10.81(2),c = 22.12(4) Å, β = 129.2(4)°,Z = 4 molecules per cell. Intensity data were collected by diffractometer and the structure refined to a conventionalRof 0.051.

ISSN:0008-4042    

DOI:10.1139/v79-026

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Reaction of hexamethylditin with haloacetic acids results in the production of 1,1,2,2-tetramethyl-1,2-diacyloxyditin(IV) compounds in good yield. Infrared, Raman,1H and13C nmr, and119Sn Mössbauer data have been interpreted in terms of a tetramethylditin species asymmetrically bridged by two acyloxy groups to give each tin a five-coordinate environment.

ISSN:0008-4042    

DOI:10.1139/v79-027

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The coordinating properties of the tridentate tris-chelating ligand, [Me2Ga(OCH2CH2NH2)(N2C3H3)]−, and its three methyl substituted derivatives (methyl substitution on the amino nitrogen and the 3,5 positions of the pyrazolyl ring) have been studied in a series of molybdenum, tungsten, and manganese carbonyl compounds. Mixed allyl carbonyl and nitrosyl carbonyl compounds of both molybdenum and tungsten have been characterized, and a series of tricarbonyl manganese compounds studied. All the complexes are monomeric octahedral species having the tris-chelating ligands infaccoordination. Steric factors influence the arrangement of the three remaining groups in the mixed octahedral complexes (i.e. allyl carbonyl and nitrosyl carbonyl derivatives) and particular site preferences are inferred from spectroscopic measurements.

ISSN:0008-4042    

DOI:10.1139/v79-028

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The crystal structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, (PhPSi2Me4)2, has been determined by single crystal X-ray diffraction. The crystals are monoclinic, space groupP21/c, witha = 9.866(1),b = 11.921(1), andc = 11.324(2) Å, β = 104.31(1)°,Z = 2, and ρcalcd = 1.15 g/cm3. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a finalRof 0.060 andRwof 0.078, for 1173 reflections with intensities greater than 3σ. The (PhPSi2Me4)2molecule lies on a crystallographic centre of symmetry, and the six-membered P2Si4ring has a chair conformation with equatorial phenyl groups. The endocyclic angles at P (104.4(1)°) and Si (104.9(2)°) are intermediate between those found in cyclic hexaphosphine and hexasilane molecules, and the Si—Si and P—Si distances of 2.345(3) and 2.252(4) Å, respectively, correspond to single bond lengths, with no appreciable evidence for secondarypπ → dπ bonding between phosphorus and silicon. The Si—C (1.867(8) Å) and P—C (1.828(7) Å) bond lengths are also normal. The variations in the Si—P—C (101.6(2)°, 108.6(2)°), P—Si—C (range 106.2(3)–120.0(3)°), and Si—Si—C (range 105.8(3)–113.7(3)°) angles indicate that the positions of the exocyclic methyl and phenyl groups are influenced by both intra- and intermolecular steric forces.

ISSN:0008-4042    

DOI:10.1139/v79-029

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Rhodium(I)–bis(ditertiaryphosphine) complexes of the general formulan = 1–4, and (+)-diop (diop = 2,3-O-isopropylidene 2,3-dihydroxy-1,4-bis(diphenylphosphino)butane) have been prepared by treating [Rh(cyclooctene)2Cl]2with the appropriate ditertiaryphosphine. Then = 1 andn = 4 and diop species are five-coordinate in the solid state and in non-polar solvents, while then = 2 and 3 species contain ionic chloride. The cationic complexeswere prepared from thespecies by adding AgX (X = SbF6, PF6, BF4). Reaction of the chloro complexes with borohydride has yielded the hydrides,for then = 2 and 3 diphosphines, and for (+)-diop.1H and31P nmr, as well as visible spectral data, are presented: a solvent-dependent deshielding oforthoprotons of the phenyl groups is observed in some of the complexes, and the ligand CH2protons are coupled to the rhodium in the Rh(Ph2PCH2PPh2)2+cation; the P atom in this bis(diphenylphosphino) ligand shows an usual high field shift on coordination to rhodium.Preliminary kinetic data for catalytic hydrogenation of methylenesuccinic acid show that the cationic and hydrido complexes are more active than the corresponding chloro complexes, and that activity generally increases with increasing chain length of the diphosphine.

ISSN:0008-4042    

DOI:10.1139/v79-030

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The dissolution of iron from carbon steel in aqueous H2S solutions has been studied as a function of time and temperature at 0.1 MPa H2S pressure using the rotating disc technique. The iron sulfide film formed on the disc surface has been identified by X-ray diffraction analysis. The solubility and dissolution rate of synthesized mackinawite, FeS(1−x), have also been determined to help establish the mechanism of release of iron from carbon steel corroding in aqueous H2S solutions.The rate data have been analysed by an equation for a joint chemical and transport controlled process. At 22 °C and 0.1 MPa H2S, the maximum rate of release of Fe2+, obtained by extrapolating the data to infinite rotation speed, is 7.4 ± 0.5 μmol/m2s. This is similar to the dissolution rate determined for synthesized mackinawite powders, but is 20 times faster than the rate of dissolution for troilite and more than 1000 times faster than the dissolution rates for pyrrhotite and pyrite. Thus, troilite and iron sulfide phases that form subsequently are not major contributors to Fe2+release during the corrosion of carbon steel.At 22 °C the diffusion coefficient for the FeSH+ion is (1.4 ± 0.2) × 10−9 m2/s and the activation energy of the diffusion process is 25 ± 7 kJ/mol. The chemical reaction occurring at the surface has an activation energy of 77 ± 14 kJ/mol.It is concluded that the release of iron from corroding carbon steel is governed by the dissolution rate of mackinawite, the initial corrosion product. This dissolution is controlled by the chemical reaction between mackinawite and H+and by the transport of the complexed FeSH+from the interface to the bulk solution.

ISSN:0008-4042    

DOI:10.1139/v79-031

出版商:NRC Research Press    

年代:1979

数据来源: NRC