Showing papers in "Journal of The Chemical Society A: Inorganic, Physical, Theoretical in 1966"
TL;DR: In this paper, the tris(triphenylphosphine) complexes are exceedingly active catalysts for the rapid and homogeneous hydrogenation, at ca. 1 atmosphere of hydrogen pressure and room temperature, of unsaturated compounds containing isolated olefinic and acetylenic linkages.
Abstract: Tris(triphenylphosphine)chlororhodium(I), RhCl(PPh3)3, has been prepared by the interaction of an excess of triphenylphosphine with rhodium(III) chloride hydrate in ethanol; the corresponding bromide and iodide are also described. The dissociation of the complex in various solvents has been investigated, and its reactions with hydrogen, ethylene, and carbon monoxide and aldehydes studied. Dihydrido- and ethylene complexes have been isolated and studied by nuclear magnetic resonance (n.m.r.) spectroscopy. Approximate values for the formation constants of ethylene and propylene complexes have been obtained; the latter is lower by a factor of over 103. By electron spin resonance spectroscopy, the complex RhCl(PPh3)3 has been shown to contain trace amounts of a paramagnetic species, probably a rhodium(II) complex.In homogeneous solution the tris(triphenylphosphine) complexes are exceedingly active catalysts for the rapid and homogeneous hydrogenation, at ca. 1 atmosphere of hydrogen pressure and room temperature, of unsaturated compounds containing isolated olefinic and acetylenic linkages.The rates of hydrogenation of hept-1-ene, cyclohexene and hex-1-yne have been studied quantitatively and the dependence on factors such as substrate and catalyst concentration, temperature, and pressure determined. The data can be accommodated by a rate expression of the form: Rate =Kp[S][A]//1 +K1p+K2[S] where [S] and [A] are the olefin and catalyst concentrations, respectively, and p is the concentration of hydrogen in solution.From the data for cyclohexene the activation energy for the rate determining step is Ea= 22·9 kcal. mole–1(ΔH‡= 22·3 kcal. mole–1) and the value of ΔS‡= 12·9 e.u.It is shown that the rate of hydrogen–deuterium exchange under selected conditions is quite slow compared with the rates of hydrogenation of olefins and, furthermore, that when H2–D2 mixtures are used in the reactions, alkanes and dideuteroalkanes are the major products. Reductions of maleic and fumaric acids with deuterium shows that cis-addition occurs preferentially. Similarly, in the reduction of hex-2-yne to n-hexane, cis-hex-2-ene is found to be the major olefin intermediate.A mechanism for the hydrogenation is proposed in which the metal complex serves as a template to which a hydrogen molecule and an olefin molecule are briefly co-ordinated before transfer of one to the other takes place. The low kinetic isotope effect (rate H2/rate D2= 0·9) suggests that synchronous breaking of Rh–H bonds and making of C–H bonds takes place in the transition state involving two simultaneous three-centre interactions.
955 citations
TL;DR: In this paper, the s-component of the platinum-phosphorus bonds is analyzed in terms of the trans-effect of the ligand to weaken the bond trans to itself and its relation to the trans effect is considered.
Abstract: The 195Pt–31P nuclear spin coupling constants, ranging between 1462 and 5698 c./sec., of twenty-five platinum complexes are reported and discussed in terms of the s-component of the platinum–phosphorus bonds. The trans-influence is defined as the tendency of a ligand to weaken the bond trans to itself, and its relation to the trans-effect is considered. It is shown that the high trans-influence of phosphorus is probably due to a σ-bonding mechanism and makes a significant contribution to the high trans-effect of phosphorus ligands. Some 31P chemical shifts are reported.
187 citations
TL;DR: The structure of the trans-isomer is essentially the same as that at room temperature reported by Porai-Koshits as mentioned in this paper, and the only angle significantly different from 90° is Cl−Pt−Cl = 91·9°± 0·4° in the cis-compound.
Abstract: Complete three-dimensional X-ray crystal structure analyses have been carried out on both compounds by identical experimental and computational methods. Observations were collected at 120°± 5°K and the intensities corrected for absorption. Hydrogen atoms were not located. After anisotropic refinement by least-squares, R is 0·091 for the cis-isomer and 0·077 for the trans-isomer. The bond lengths, corrected for rotational oscillation are Pt–Cl = 2·33 ± 0·01 A and Pt–N = 2·01 ± 0·04 A in the cis-compound, and Pt–Cl = 2·32 ± 0·01 A and Pt–N = 2·05 ± 0·04 A in the trans-compound. The only angle significantly different from 90° is Cl–Pt–Cl = 91·9°± 0·4° in the cis-compound.The crystals of cis-dichlorodiammineplatinum are triclinic with two molecules in a unit cell having a= 6·75, b= 6·55, c= 6·23 A, α= 92·2°, β= 84·6°, and γ= 110·7°, and space group P. The molecules lie approximately parallel to (100) at x/a∼¼ and ∼¾, with platinum–platinum separations alternately 3·372 and 3·409 A perpendicular to the molecular planes. At low temperature the structure of the trans-isomer is essentially the same as that at room temperature reported by Porai-Koshits.
154 citations
TL;DR: In this article, the magnetic susceptibilities of five compounds of tervalent chromium and seven compounds of tricarboxylate iron have been measured over the range of temperature 80-300°K.
Abstract: The magnetic susceptibilities of five compounds of tervalent chromium and seven compounds of tervalent iron have been measured over the range of temperature 80–300°K. The compounds are formulated with a trimeric cation in which two carboxylate groups bridge each of the sides of the equilateral triangle, whose vertices are the metal atoms and whose centre is an oxygen atom. The exchange integrals of magnetic interaction derived from the measurements are compared with values known in other M–O–M systems. Measurements of the susceptibilities of some of the compounds in water show that the trimeric cation is maintained in solution.
142 citations
TL;DR: Pyridine molecules form strong hydrogen bonds with pyridinium ions in the interlayer space of montmorillonite, causing a marked perturbation of vibrations involving the NH+ group as mentioned in this paper.
Abstract: Pyridine molecules form strong hydrogen bonds with pyridinium ions in the interlayer space of montmorillonite, causing a marked perturbation of vibrations involving the NH+ group. These vibrations are not perturbed by interlayer benzene. Water molecules directly co-ordinated to Ca2+ and Mg2+ form strong hydrogn bonds with pyridine which readily displaces water from outer spheres of co-ordination round these ions. Preparations with a 14·7 A layer spacing appear to contain the complex M2+(HOH,NC5H5)6. Wider spacings (about 23 A) are obtained when pyridine is hydrogen-bonded to both protons of co-ordinated water. Pyridine co-ordinates to Cu2+ both directly and also indirectly through water. Hydrogen-bonding in these complexes is stronger than in aqueous pyridine, as the acidity of co-ordinated water is increased by the polarising forces of the metal cations. The linking water molecules can be reversibly removed from Ca2+ and Cu2+ complexes but not from the Mg2+ complex, where residual water molecules ionise to give pyridinium ions on heating in a vacuum. This reaction is also reversible. Pyridinium ions are formed when co-ordinated pyridine is displaced by water, in amounts dependent on the basicity of the cation. Deeply coloured anhydrous complexes of Cu montmorillonite, formed in hot pyridine or on long treatment in the cold, may contain basic copper ions. Some differences between saponite and montmorillonite complexes can be related to differences in the surface density of exchange sites.The dependence of the intensity of absorption bands on the angle of incidence of radiation on montmorillonite films gives information on the orientation of pyridine molecules in the interlayer space, and assists in the assignment of symmetry species to vibrations. The use of pyridine as an indicator of Lewis and Bronsted acidity on surfaces is discussed.
120 citations
TL;DR: Raman and infrared spectra of aqueous solutions of vanadates have been studied from pH 8 to > 14, and assignments are proposed for the vibrational frequencies of (VO4)3, (HVO4)-2, (V2O7)-4, (VO3)nn-1, and VO3)3-1 as discussed by the authors.
Abstract: Raman and infrared spectra of aqueous solutions of vanadates have been studied from pH 8 to > 14, and assignments are proposed for the vibrational frequencies of (VO4)3–, (HVO4)2–, (V2O7)4–, (HV2O7)3–, and (VO3)nn–. It appears that there is tetrahedral co-ordination of the vanadium in all these ions.
81 citations
TL;DR: By variation of the proton levels of donors (mono-, di-, tri-chloroacetic acid) and acceptors (sulphoxides, phosphine oxides, a selenoxide, pyridine N-oxide) a series of adducts was obtained which made possible the investigation of the effects of increasing strength of the hydrogen bond on the spectra as discussed by the authors.
Abstract: By variation of the proton levels of donors (mono-, di-, tri-chloroacetic acid) and acceptors (sulphoxides, phosphine oxides, a selenoxide, pyridine N-oxide) a series of adducts was obtained which made possible the investigation of the effects of increasing strength of the hydrogen bond on the spectra. The latter may be grouped into two distinct types: (i) the region 1800–3000 cm.–1 contains three main bands connected with OH vibrations, and (ii) no such band is in this region, but a strong and broad feature appears at much lower frequencies. Possible origins of these and other spectral characteristics are discussed.
69 citations
TL;DR: In this article, the interconversion of these compounds with uranium(VI) compounds is described, and the paramagnetic susceptibility of the uranyl ion in these complexes (86−147 × 10−6 e.m.u/g.
Abstract: Twenty complexes of uranium(VI), of the type [UO2A2B2]z(A, B = Cl, Br, I, Ph3PO, or Et3PO; the charge z=+ 2, 0, or –2), have been prepared and characterised. The interconversion of these compounds with uranium(VI) compounds is described. Infrared measurements show that (i) the phosphine oxide and chloro-complexes have trans configurations, (ii) the asymmetric stretching frequency of the uranyl group varies irregularly with A and B, and (iii) the symmetric stretch of the uranyl group is active in some cases, probably owing to hydrogen-bonding with (R3PH)+ cations. The paramagnetic susceptibility of the uranyl ion in these complexes (86–147 × 10–6 e.m.u./g.mol.) is independent of temperature. Finally, it is suggested that the previously reported tertiary phosphine complexes of uranium(IV) and uranium(VI), [UX4(R3P)2] and [UO2X2(R3P)2](R = Et, Prn, or Ph; X = Cl, Br, or I), are [R3PH]2[UO2X4] and [UO2X2(R3PO)2], respectively.
66 citations
TL;DR: In this paper, new complexes of platinum(II) and palladium (II) with dimethylphenylphosphine are described, and 1H nuclear magnetic resonance data for these complexes, and for simple derivatives of DPHP, e.g., oxide and sulphide, are given.
Abstract: New complexes of platinum(II) and palladium(II) with dimethylphenylphosphine are described. 1H Nuclear magnetic resonance data for these complexes, and for simple derivatives of dimethylphenylphosphine, e.g., the oxide and sulphide, are given. The phenomenon of “virtual” coupling is discussed briefly and used to study cis/trans isomerism in these complexes. trans-Di-iodobis(dimethylphenylphosphine)palladium(II) is unusual in having a red polymorph in which the palladium is co-ordinated to three iodine atoms and possibly weakly co-ordinated to β-hydrogen atoms on the phenyl rings.
62 citations
TL;DR: In this article, the effect of replacing the air over the reactant by argon has been examined and it is concluded that atmospheric oxygen does not participate in the reaction and that, under isothermal conditions, the decomposition divides into two consecutive but overlapping parts, namely: (a) the initial decomposition of sodium nitrate to sodium nitrite, and (b) the subsequent breakdown of sodium oxide to form sodium oxide.
Abstract: The kinetics of the thermal decomposition of molten sodium nitrate have been studied as a function of temperature in the range 570–760°. The effect of replacing the air over the reactant by argon has been examined. From these measurements, it is concluded that atmospheric oxygen does not participate in the reaction and that, under isothermal conditions, the decomposition divides into two consecutive but overlapping parts, namely: (a) the initial decomposition of sodium nitrate to sodium nitrite, and (b) the subsequent break-down of sodium nitrite to form sodium oxide. A mechanism is postulated.
60 citations
TL;DR: In this article, the reaction of tris(triphenylphosphine)chlororhodium(I) with iodomethane is shown to give an octahedral complex of rhodium (III), [RhlCl(CH3)(PPh3)2(ICH3)], which contains not only a Rh-CH3 group, but also unusually, a firmly co-ordinated I-I molecule.
Abstract: The reaction of tris(triphenylphosphine)chlororhodium(I) with iodomethane is shown to give an octahedral complex of rhodium(III), [RhlCl(CH3)(PPh3)2(ICH3)], which contains not only a Rh–CH3 group, but also unusually, a firmly co-ordinated iodomethane molecule.From the interaction of RhCl(PPh3)3 with allyl and 2-methylallyl chloride, the first simple allylic derivatives of rhodium are obtained. These compounds fall into three classes. The allylic group is σ-bonded in one class, π-bonded in the second, and σ+π-bonded in the third.The complexes are characterised, inter alia, by nuclear magnetic resonance spectroscopy.
TL;DR: By heating trans-ReOX3(PPh3)2 with a variety of carboxylic acids or their anhydrides, this article isolated not only the known compounds ReX4 (PPh 3)2 and Re2Cl2(R·CO2)4 but also the new series of Carboxylato-complexes.
Abstract: By heating trans-ReOX3(PPh3)2 with a variety of carboxylic acids or their anhydrides we have isolated not only the known compounds ReX4(PPh3)2 and Re2Cl2(R·CO2)4 but also the new series of carboxylato-complexes, Re2Cl3(R·CO2)2(PPh3)2, Re2OX5(R′·CO2)(PPh3)2, and Re2Br2(R·CO2)4(X = Cl or Br, R = alkyl, R′= alkyl or aryl). The relative proportions of these compounds depend, inter alia, on the duration of heating, the amount of oxygen present, and the strength of the acid used. Convenient preparative routes to the compounds ReCl4(PPh3)2 and Re2Cl2(R·Co2)4 are described.
TL;DR: In this paper, the spectral properties of a number of normal and isotopically substituted binuclear complexes with single bridge groups have been studied, and assignments of the skeletal modes and structures of the complexes discussed; assignments are also suggested for metal-nitrogen stretches in cobalt and chromium ammines.
Abstract: Infrared spectra of a number of normal and isotopically substituted binuclear complexes with single bridge groups have been studied. Assignments of the skeletal modes are suggested and the structures of the complexes discussed; assignments are also suggested for metal–nitrogen stretches in cobalt and chromium ammines.
TL;DR: Improved methods of preparing salts of the oxopentachlororhenate(V) ion, [ReOCl5]2, are given and the magnetic properties of Cs2ReOCL5 are discussed in this article.
Abstract: Improved methods of preparing salts of the oxopentachlororhenate(V) ion, [ReOCl5]2–, are given and the magnetic properties of Cs2ReOCl5 are discussed. The hydrolysis of rhenium pentachloride in the presence of triphenylphosphine leads to the formation of rhenium(III) complexes. The reaction products of trans-dioxobis(ethylenediamine)rhenium(V) chloride with hydrochloric acid are reformulated. The visible spectra of some trans-dioxo-, oxohydroxo- and bis(hydroxo)rhenium(V) compounds are discussed.
TL;DR: In this paper, the magnetic properties for the 3T1g term under simultaneous perturbation by spin-orbit coupling and an asymmetric (trigonal or tetragonal) ligand field is presented.
Abstract: The behaviour of the magnetic properties for the 3T1g term under simultaneous perturbation by spin–orbit coupling and an asymmetric (trigonal or tetragonal) ligand field is presented. The theory is applied to the variation in the magnetic properties of nineteen nickel(II) tetrahedral complexes over the temperature range 80–300°K. The magnetic moments of the complexes are related mainly to the orbital reduction factor k, and the reduction from the free-ion value of the spin–orbit coupling constant for the metal ion in the complex. The value of Δ, the axial ligand field splitting, appears to be constant and not directly related to the symmetry of the complexes.
TL;DR: In this article, the densities of lithium, sodium, potassium, and caesium chloride solutions up to 200° were determined by a mercury displacement method, and values of the apparent molal volume of the salts and of the limiting partialmolal volume, ϕ°, were reported.
Abstract: The densities of lithium, sodium, potassium, and caesium chloride solutions up to 200° were determined by a mercury displacement method. Values of the apparent molal volume of the salts and of the limiting partial molal volume, ϕ°, are reported. ϕ° for the alkali chlorides passes through a maximum at about 60°(LiCl at 40°) and by 200° falls to a value ranging from –7·6 for LiCl to 23·6 for CsCl (16–24 units lower than at 25°). The values of ϕ° are related to the density of water, and are correlated by the equations for intrinsic volume of the ions and for the electrostriction effect as suggested by Glueckauf.
TL;DR: The nickel(II) complex of the quadridentate heterocycle hexamethyl-1,4,8,11-tetra-azacyclotetradecadiene as mentioned in this paper occurs in two non-interconvertible isomeric forms, considered due to cis and trans arrangements of the heterocycling ring components.
Abstract: The nickel(II) complex of the quadridentate heterocycle hexamethyl-1,4,8,11-tetra-azacyclotetradecadiene [formed by reaction of trisdiaminoethanenickel(II) with acetone] occurs in two non-interconvertible isomeric forms, considered due to cis and trans arrangements of the heterocycle ring components. One of these isomers occurs as two inter-convertible forms, considered to be conformational isomers stabilized by steric hindrance. The perchlorate and tetrachlorozincate salts of the three isomers are described.
TL;DR: In this paper, the relative viscosities of solutions of sodium and potassium chlorides and bromides in N-methylformamide have been determined at 25, 35, and 45°.
Abstract: The relative viscosities of solutions of sodium and potassium chlorides and bromides in N-methylformamide have been determined at 25, 35, and 45°. Values of the coefficients A, B, and D in the extended Jones–Dole equation ηr= 1 +Ac½+Bc+Dc2, have been obtained after applying a solvent correction. The A-values are in fair agreement with those predicted from the interionic-attraction theory. The B-values are all positive, are additive for single ions, and decrease with increase in temperature. A comparison of the B-values with those for electrolytes in other organic solvents and in water allows a tentative general interpretation of the trends in these values from solvent to solvent to be made.
TL;DR: In this article, the electrical conductivity and 19F and 1H nmr spectra of the hydrogen fluoride-antimony pentafluoride system are accounted for in terms of the reactions 2HF+SbF5 H2F++ SbF6−, and SbFs6−+nSbFs5→[Sbn+1 F5n+1]
Abstract: The electrical conductivity and 19F and 1H nmr spectra of the hydrogen fluoride–antimony pentafluoride system are accounted for in terms of the reactions 2HF + SbF5 H2F++ SbF6–, and SbF6–+nSbF5→[Sbn+1 F5n+1]– It is shown that the ion H2F+ has an abnormally high mobility and therefore probably conducts by a proton-transfer mechanism SbF4SO3F undergoes solvolysis according to the equation SbF4SO3F + 3HF → H2F++ SbF6–+ HSO3F
TL;DR: In this article, the conductance of methyl cyanide solutions of triphenyl-phosphine, arsine, stibine, and -bismuthine dihalides has been measured, and the molar conductance values are compared.
Abstract: The conductance of methyl cyanide solutions of triphenyl-phosphine, -arsine, -stibine, and -bismuthine dihalides has been measured, and the molar conductance values are compared. Conductometric titrations of some triphenylphosphine–halogen systems indicate the formation of triphenylphosphine tetrahalides which are strong electrolytes and ionise as halogenotriphenylphosphonium trihalides like their triphenylarsine analogues. Each compound in the series Ph3PlnBr4 –n has been prepared. Tetrahalides of triphenylstibine and -bismuthine could not be prepared, although Ph3Sbl4 and Ph3Sbl3Br were indicated by conductometric titration.
TL;DR: In this paper, the electronic absorption spectra of thirty-three complexes of general formula (Amine)2CoX2 where the amine is quinoline, isoquinoline, 2,6-dimethylpyrazine, pyridine, or a 2-, 3-, or 4-substituted Pyridine and X is Cl, Br, I, NCS, NCO, or NCSe, are reported.
Abstract: The electronic absorption spectra (5000–30,000 cm.–1)(in chloroform) of thirty-three complexes of general formula (Amine)2CoX2 where the amine is quinoline, isoquinoline, 2,6-dimethylpyrazine, pyridine, or a 2-, 3-, or 4-substituted pyridine, and X is Cl, Br, I, NCS, NCO, or NCSe, are reported. The near-infrared absorption band is split into three well defined components, whose overall width is some 1500–2000 cm.–1 greater than is observed in regular tetrahedral cobalt derivatives (such as CoX42–). These three components are assigned to the 4B2â†�4A2, 4A2â†�4A2, and 4B1â†�4A2 transitions in C2v symmetry. With the exception of one band the absorption spectra are virtually independent of the amine throughout the entire region studied. The supposed 4B2â†�4A2 component of the near-infrared absorption decreases in energy by as much as 1000 cm.–1 when the complex contains an α-substituted pyridine. A simple group-theoretical argument consistent with the occurrence of inter-ligand repulsions is suggested to explain this phenomenon. Mean values of 10Dq and B are computed and discussed.
TL;DR: In this paper, the complex tris(triphenylarsine)- and tris (triphenylonstibine)-chlororhodium(I) was obtained by interaction of MPh3 with bis(ethylene) chlororhodIUM(I).
Abstract: The complex compounds tris(triphenylarsine)- and tris(triphenylstibine)-chlororhodium(I)[RhCl(MPh3)3, M = As and Sb] have been prepared by interaction of MPh3 with bis(ethylene)chlororhodium(I). The complexes generally show behaviour similar to that previously described for tris(triphenylphosphine)chlororhodium(I). Although the present complexes are not as efficient as the phosphine complex as homogeneous hydrogenation catalysts for olefins, they undergo similar chemical reactions with hydrogen, ethylene, diphenylacetylene, tetrafluoroethylene, hydrogen chloride, and oxygen. The complexes obtained in these reactions have been studied by infrared and nuclear magnetic resonance spectroscopy.
TL;DR: In this paper, the tetrameric products, e.g., (MeZnON:CMe2)4 and (EtZnNPhCOEt)4, from zinc alkyls and acetoxime and phenyl isocyanate are formulated with parallel six-and eight-membered rings.
Abstract: Zinc alkyls and 2-dimethylaminoethanol eliminate hydrocarbon giving trimers (RZnO·C2H4·NMe2)3(R = Me, Et). The tetrameric products, e.g., (MeZnON:CMe2)4 and (EtZnNPhCOEt)4, from zinc alkyls and acetoxime and phenyl isocyanate are formulated with parallel six- and eight-membered rings, respectively, the interaction between the rings arising from the tendency of the metal to be four rather than three co-ordinate.The near-cubic structure of the crystalline methylzinc methoxide tetramer persists in cyclohexane solution and interaction with pyridine is slight. · The tetramer yields an adduct with 4-dimethylaminopyridine which dissociates extensively in solution to tetramer and free base.Diethylzinc eliminates ethylene quantitatively in reaction with benzophenone, giving the trimer (EtZnOCHPh2)3. Diphenylzinc adds to the carbonyl group forming a dimer, (PhZnOCPh3)2.
TL;DR: Acyl derivatives of the type trans-[MX(COR)(PEt3)2]-M = Pt or Pd; X = Cl, Br, or I; R = Me, Et, or Ph) have been prepared by the action of carbon monoxide on alkyl and aryl derivatives.
Abstract: Acyl derivatives of the type trans-[MX(COR)(PEt3)2](M = Pt or Pd; X = Cl, Br, or I; R = Me, Et, or Ph) have been prepared by the action of carbon monoxide on alkyl and aryl derivatives of the type [MXR(PEt3)2]. Carbon monoxide reacts with the complex cis-[PtMe2(PEt3)2] to give a novel carbonyl complex [Pt3(CO)n(PEt3)4](n= 3 or 4) and biacetyl. Other related disubstituted derivatives gave either unstable or intractable products. Some alkyl and aryl platinum and palladium derivatives were too unstable to be carbonylated, or gave carbonylated products too unstable to isolate.
TL;DR: Complexes have been prepared between iron(II), copper (II), zinc(II, and cadmium(II) halides and pyridine, α-, β-, and γ-picoline, 2,6-lutidine, and 2,4-6-collidine as mentioned in this paper.
Abstract: Complexes have been prepared between iron(II), copper(II), zinc(II), and cadmium(II) halides and pyridine, α-, β-, and γ-picoline, 2,6-lutidine, and 2,4,6-collidine. Where possible, structural types are identified. The present complexes are compared with similar compounds of chromium(II), manganese(II), cobalt(II), and nickel(II).
TL;DR: The chemical shifts of the CH and CH3 protons in the nuclear magnetic resonance spectra of many neutral β-diketone complexes are shown to be sensitive to the electrical symmetry of the molecule as mentioned in this paper.
Abstract: The chemical shifts of the CH and CH3 protons in the nuclear magnetic resonance spectra of many neutral β-diketone complexes are shown to be sensitive to the electrical symmetry of the molecule. The effects are ascribed largely to intramolecular linear electric-field shifts and can be calculated from the dipole moment of the molecule. The signs of the shifts can be used in discussing the structure of the complexes; they confirm the cis configuration for titanium(IV), germanium(IV), and tin(IV) complexes of the type M(acac)2Cl2, and the existence of two C-bonded (acac) ligands in [Pt(acac)3]–. The large low-field shift of CH recently observed in [Si(acac)3]+ is also ascribed to both first- and second-order electric-field shifts rather than to any marked benzenoid resonance in the β-diketone ring.
TL;DR: A series of pyridine, γ-picoline, and quinoline complexes have been prepared with manganese, cobalt, nickel, copper, and zinc perchlorates and tetrafluoroborates as mentioned in this paper.
Abstract: A series of pyridine, γ-picoline, and quinoline complexes have been prepared with manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) perchlorates and tetrafluoroborates. The pyridine and γ-picoline complexes have the general formula M(L)4(ClO4)2 or M(L)4(BF4)2. With quinoline, two series of complexes were prepared. The first had the formula MQ2(ClO4)2 and MQ2(BF4)2 and the second MQ2F(BF4). The ultraviolet and visible reflectance spectra, infrared spectra, and magnetic properties of these compounds have been measured and are discussed.
TL;DR: In this article, the magnetic susceptibilities of four iron(III) and five ruthenium (III) compounds, all with the low-spin configuration t52g, have been measured in the range 80-300°K.
Abstract: The magnetic susceptibilities of four iron(III) and five ruthenium(III) compounds, all with the low-spin configuration t52g, have been measured in the range 80–300°K. The data are compared with the theory for a 2T2g ground term in the presence of a low-symmetry ligand-field component, and including electron delocalisation. The splitting of the orbital degeneracy of the term is estimated to be about 500 cm.–1 in each of the iron compounds, but varies from 0 to 1000 cm.–1 in the ruthenium compounds. The amount of t2g electron delocalisation is small in the iron complexes, and in all but one of the ruthenium complexes.
TL;DR: In this article, the electronic spectra have been recorded for a series of octahedral compounds [M(bipy)2X2], where M = Fe, Ru, and Os, X,X′= Cl, Br, and I, and X2= 2,2′-bipyridyl.
Abstract: Electronic spectra have been recorded for a series of octahedral compounds [M(bipy)2X2] and [M(bipy)2X2]X′, where M = Fe, Ru, and Os, X,X′= Cl, Br, and I, and X2= 2,2′-bipyridyl. Certain of the electronic spectral bands have been assigned to metal-oxidation and metal-reduction spectra. Shifts in these bands have, in some cases, been correlated with the bonding between metal and ligand.
TL;DR: In this article, it was shown that the oxidation of the hydroxylammonium cation by ceric sulphate occurs more slowly at higher concentrations of sulphuric acid and appears to involve prior co-ordination of hydroxyl acid to cerium.
Abstract: The oxidation of the hydroxylammonium cation by ceric sulphate occurs more slowly at higher concentrations of sulphuric acid and appears to involve prior co-ordination of hydroxylamine to cerium. The radical first formed is oxidised further except at low cerium concentrations.