Lead(II) halides (PbX2 where X = Cl, Br, and I) formed five types of adducts with monodentate (L) and bidentate (LL) ligands: PbX2•L, PbX2•2L, 2PbX2•L, PbX2•LL, and PbX2•2LL, but not all halides and ligands produced each type. Monodentate ligands were dimethylsulphoxide, N,N-dimethylacetamide, N,N-dimethylthioacetamide, thioacetamide, 2,6-dimethyl-γ-pyrone, N-methyl-2-pyridone, N-methyl-2-pyrollidinone, thiourea, pyridine, piperidine, and aniline, while bidentate ligands were ethylenediamine, tetramethylethylenediamine, 1,10-phenanthroline, and 2,2′-bipyridine. Infrared and Raman spectra are reported together with ligand vibrational frequencies shifted by coordination. Under similar experimental conditions qualitative trends in acceptor and donor abilities appeared to be PbI2 > PbBr2 > PbCl2 and S-donors > O-donors, respectively.
A new series of octahedral cobalt(II) complexes are formed when CoX2(X = Cl, Br, I, SCN) reacts with Hg(SCN)2 in the presence of Lewis bases. These complexes of stoichiometry CoHg(SCN)4•2L (L = THF, dioxane, pyridine, aniline) are pink to violet solids which slowly decompose to the blue crystalline solid, CoHg(SCN)4, the stable magnetic susceptibility standard. On further reaction of CoHg(SCN)4•2THF with mono-, bi-, and polydentate ligands in dry ethanol, complexes of the following types are obtained: CoHg(SCN)4•2L (L = PΦ3), CoHg(SCN)4•2LL (LL = trien), CoHg(SCN)4•3LL (LL = en, bipy), and CoHg(SCN)4•4LL (LL = phen). The stoichiometry of these were determined by elemental analysis. Possible structures of these are discussed with the help of mid and far infrared, visible, and ultraviolet spectroscopy, magnetic susceptibility, and X-ray powder diffraction. Some new i.r. bands like Co—P, Co—N, and Hg—S are assigned in the low region.
The preparation, properties, and vibrational spectra are reported for the following complexes of lead(II) thiocyanate with mono- and bidentate ligands: Pb(NCS)2•2py, Pb(NCS)2•phen, Pb(NCS)2•2phen, Pb(NCS)2•tmen, Pb(NCS)2•en, Pb(NCS)2•2en, Pb(NCS)2•2dmso, and Pb(NCS)2•2dma. Assignments are made for the ν(CN), ν(CS), and δ(NCS) vibrational bands of the thiocyanate group and the results are discussed in terms of the type of coordination of NCS with lead(II). Values are consistent with bridge-bonded and/or N-bonded thiocyanate. Infrared and Raman spectra of the complexes Pb(NCS)2•bipy and Pb(NCS)2•4tu are reexamined and new assignments are made which support bridge-bonded and/or N-bonded NCS contrary to previous reports of S-bonded NCS.
Dilute carbon tetrachloride solutions of chromyl chloride and toluene react to form a product of empirical composition, C6H5CH3.2CrOZClZ (1). On refluxing 1 with carbon tetrachloride solutions of pyridine, a-picoline, acetonitrile, dioxan, tetrahydrofuran, and triethylamine, adducts of approximate compositions C6H5CH3.2CrOzC1,.2D (D = donor molecule) are obtained.Results of magnetic susceptibility, infrared, and preliminary X-ray observations are discussed. Possible structures for 1 and for the ternary adducts are described.
The crystal and molecular structure of the title compound has been determined from three-dimensional X-ray data.Crystals are monoclinic, space group P2,/c, a = 17.385(9), b = 10.581 (4). c = 19.304(5) 8, p = 91 -41 (6)". and Z = 4. The structure was solved from diffractometer data by the heavy-atom method and refined by least-squares procedures to R 0.048 for 2769 observed reflections. The cell contains monomeric molecules and the mercury atom is in a distorted tetrahedral environment, as previously suggested on the basis of the i.r. spectrum. Bond lengths are: Hg-S 2.565 and 2.577. and Hg-P 2.487 and 2.484 A.MERCURY (11) halide complexes with tertiary aliphatic phosphines and arsines are well kn0wn.l Similar triphenylphosphine complexes of empirical formulae HgX,(PPh,) and/or HgX,(PPh,), have been reported 2-4 for X = SCN, CN, Cl, Br, I, NO,, and C10,; structural information available has generally been obtained from their vibrationalWe have recently determined the crystal structure of Ng(SCN),(AsPh,),6 for which a dimeric structure with bridging thiocyanato-groups had been suggested on the basis of the i.r. ~p e c t r u m . ~ The crystal was found to contain discrete three-co-ordinate molecules. This prompted us to investigate the structure of a 1 : 2 addition complex and the triphenylphosphine compound was selected.
Viscosity data for ammonia, methylamine, and 1,2-diaminopropane have been obtained in the temperature ranges -65 to -35, -65 to -10, and -35 to + 50 "C, respectively, using an Ubbelohde viscometer. The results were compared with existing data, and all the data were fitted to the Fulcher (Tammann-Hesse) equation by the method of least squares. The significance of the values of To in this equation for these and other associated liquids was considered. Canadian Journal of Chemistry, 48, 1214 (1970) In the search for a simple equation to express the dependence of the viscosity, q, of liquids on absolute temperature, T, over an extended range, the equation apparently first proposed by Fulcher (1) and used by Tammann and Hesse (2), Prasad (3), Gut~uann and Simmons (4, 5), and recently by Miller (6), has been somewhat neglected. Part of this neglect may be due to the fact that it is not simply explicable in terms of an "activation energy for flow."Gutmann and Simmons showed that eq.[l ] is obtained if the activation energy, Eo, varies with temperature as Eo/(a + b/T), where a and b are constants. This, however, is an unsatisfying form, hard to relate to molecular or thermodynamic concepts. They also succeeded in deriving the equation from what they described as a quantum form of the Maxwell-Boltzmann distribution law, attributingthe deviation ofthe viscosity from the Andrade equation (7) Gutmann and Simmons have derived normal equations for least-squares fitting of eq.[ l ] to data, but we prefer eqs.[3] for this purpose, as they throw less undue weight on the highertemperature points.where y = log q, T = absolute temperature, D = B -AT,, and A, B, and To are the constants in eq. [ll.Using a computer, we have fitted the Fulcher equation to data for the viscosity of several oxygen-and nitrogen-containing associated liquids. The results are listed in Table 3. Data for the alcohols, glycol, and glycerol were obtained from various literature sources (8-10). Data for ammonia in the literature were included with our own, and our own data were used for methylamine and 1,2-diaminopropane.where A' is a constant and R is the gas constant, Experimental t o other causes than inconstancy of E. It must beThe -/iscosities of liqtiid ammonia, methylamine, and admitted that the theoretical justification for eq. 1,2-diaminopropane were measured by capillary flow,
The surface tensions of methanol, acetone, dimethylformamide, dimethylsulfoxide, and methylamine over limited temperature ranges, and of solutions of alkali halides in the first three of these liquids at 25 "C have been measured bv the method of maximum bubble pressure, with precautions against moisture. The data for the pure liquids are compared with literature data where these exist. The results for the solutions are discussed in the light of various existing theories.On a determine la tension superficielle du methanol, de I'acbtone, de la dim6thylformamide, du dimethylsulfoxyde et de la mtthylamine dans des intervalles IlmitCs de temperature, ainsi que des solutions dans les trois premiers liquides a 25 "C, par la mkthode de Sugden, a I'abri de I'humidite. Les valeurs obtenues pour les liquides purs ont CtC cornparees aux valeurs reconnues, la oh ces valeurs existent. Les resultats pour les solutions ont kt6 considCrCs dans le contexte des theories diverses dkja avanckes. Canadian Journal o f Chemistry, 48, 2755 (1970)A number of theories have been proposed for the surface tension of salt solutions. They agree in predicting that dissolved salts should raise the surface tension of molecular solvents, and they agree roughly with one another and with experiment in the magnitude of the effect. Only one of them (1) predicts substantial differences among salts of the same charge-type in a given solvent, though such differences are readily apparent in the data (2).The simplest of these theories, in the form of the dependence of the surface-tension increment,, on the concentration of salt in the bulk solution, c, is that of Oka (3). He makes a direct calculation of the work required, against the additional forces arising from the presence of dissolved ions, to divide a solution into two portions, thereby creating new surfaces. His result is of the form E the dielectric constant of the solvent, and a is the "apparent degree of dissociation" of the salt. For strong electrolytes at low concentration this reduces to a linear dependence on concentration.The theory of Wagner (4) is based on the calculation, first, of the degree to which ions are excluded from the surface by interaction of their fields with the change in dielectric constant at the surface. The change in the surface tension is then calculated using the Gibbs adsorption isotherm. It was not expressed in analytical form, but the approximation of Onsager and Samaras (5), while also not in analytical form at higher concentrations, yielded a limiting law at low concentrations of the form This expression is expected to be valid only at concentrations much smaller than the numerator of the argument of the logarithm. It is effectively of the form: -Kc log c, which approaches the origin with infinite slope, but with such a sharp curvature that it is doubtful if this will ever be experimentally testable. (The problem of obtaining a sufficiently pure solvent gives one pause.) Wagner's numerical calculation agrees closely with the limiting law below 0.01 mole/l in aqueo...
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