Showing papers in "Bulletin of the Chemical Society of Japan in 1973"
TL;DR: In this paper, the effect of the composition of binary oxides on acidity was examined for TiO2-Al2O3, ZnO-Al 2O3 and Al2O-ZrO2.
Abstract: Eighteen binary metal oxides consisting of TiO2–MmOn, ZnO–MmOn and Al2O3–MmOn (MmOn: metal oxide) were prepared by the usual co-precipitation method, their acid amounts and strengths being determined by n-butylamine titration using various acid-base indicators. The acid strengths of fourteen of the tested binary oxides of molar ratio 1 : 1 were found to be remarkably higher than those of the component single oxides. High acid strengths were as follows: H0≤−8.2 for TiO2–SiO2, H0≤−5.6 for TiO2–Al2O3 and Al2O3–ZrO2 and H0≤−3 for TiO2–CdO, TiO2–SnO2 and ZnO–SiO2. The acid amounts of sixteen binary oxides were larger than those of the component oxides. The effect of the composition of binary oxides on acidity was examined for TiO2–Al2O3, ZnO–Al2O3 and Al2O3–ZrO2. The acidity maxima appearing for TiO2–Al2O3 and ZnO–Al2O3 were found to be of molar ratio\simeq9:1 and for Al2O3–ZrO2\simeq3:2. A fairly good correlation has been demonstrated between the observed highest acid strengths and the average electronegativi...
213 citations
TL;DR: In this article, the infrared and Raman spectra of several dialkyl disulfides were measured and their conformations were discussed in relation with the characteristic S-S and C-S stretching vibrations.
Abstract: The infrared and Raman spectra of several dialkyl disulfides were measured and their conformations were discussed in relation with the characteristic S–S and C–S stretching vibrations. The infrared spectra in the solid state and the temperature dependence of Raman spectra were measured for ethyl methyl disulfide and diethyl disulfide. For ethyl methyl disulfide, the gauche-gauche isomer was more stable than the trans-gauche isomer by about 0.9 kcal/mol while for diethyl disulfide the gauche-gauche-gauche isomer was more stable than the trans-gauche-gauche isomer by about 0.6 kcal/mol in the liquid state. Only the gauche-gauche form for ethyl methyl disulfide and only the gauche-gauche-gauche form for diethyl disulfide were observed in the solid state.
184 citations
TL;DR: In this article, the authors determined the bond distances (rg) and angles (rα) in N-methylacetamide by gas electron diffraction, and the two methyl groups are in the trans conformation about the N-C (carbonyl) bond, no other conformer being observed.
Abstract: The bond distances (rg) and angles (rα) in N-methylacetamide have been determined by gas electron diffraction as follows: C–C=1.520±0.005 A, N–C (methyl)=1.469±0.006 A, N–C (carbonyl)=1.386±0.004 A C=O=1.225±0.003 A, C–H (average)=1.107±0.005 A, ∠N–C=O=121.8±0.4°, ∠C–N–C=119.7±O.8°, ∠C–C–N=114.1±1.5°, ∠H–C–H(average)=110.4±2° and ∠H–N–C(carbonyl)=110±5°. In comparison with the molecular structure in the crystal, the N–C(carbonyl) bond is about 0.10 A longer, whereas the C–C and C=O bonds are about 0.02 and 0.01 A shorter, respectively. The two methyl groups are in the trans conformation about the N–C (carbonyl) bond, no other conformer being observed.
129 citations
TL;DR: In this paper, the infrared absorption spectra of CO2 adsorbed on MgO and GaO were measured in the wide region 700-4000 cm−1 at various amounts of adorbed CO2 and temperatures of adsorption and desorption.
Abstract: The infrared absorption spectra of CO2 adsorbed on MgO and GaO were measured in the wide region 700–4000 cm−1 at various amounts of adsorbed CO2 and temperatures of adsorption and desorption. It has been found that both uni- and bidentate carbonates are formed on MgO when a small amount of CO2 is adsorbed and that unidentate carbonates predominate as the amount of adsorbed CO2 is increased. On the other hand, only unidentate species were formed on CaO at room temperature independently of the amount of adsorbed CO2, but bidentate species were also formed on CaO when the temperature of adsorption was high. The unidentate carbonates formed on both MgO and CaO at room temperature partially changed to bidentate carbonates upon evacuation at higher temperatures. The correlation between Δv=|v1–v5| and the partial charge on oxygen atoms of various oxides, which corresponds to basic strength on the surface, was examined.
123 citations
TL;DR: In this paper, the authors determined the bond distances (rg) and angles (rα) in acetamide CH3CONH2 by gas electron diffraction as follows: C−C=1.519±0.006 A, C−N=1 1.220± 0.003 A, N−H (average)=1.022±0.011 A, ∠C−C−H(average)=109.8±2°.
Abstract: The bond distances (rg) and angles (rα) in acetamide CH3CONH2 have been determined by gas electron diffraction as follows: C–C=1.519±0.006 A, C–N=1.380±0.004 A, C=O=1.220±0.003 A, C–H (average)=1.124±0.010 A, N–H (average)=1.022±0.011 A, ∠N–C=O=122.0±0.6°, ∠C–C–H (average)=109.8±2°, and ∠C–C–N=115.1±1.6° (or 112.2±1.6°). In comparison with the molecular structure in the crystal, the C–N bond is about 0.05 A longer, whereas the C=O bond is about 0.04 A shorter. The C–N and C=O bonds appear to be slightly shorter than the corresponding bonds in N-methylacetamide.
120 citations
TL;DR: In this paper, a new method for the preparation of t-butyloxycarbonyl amino acids and p-methoxybenzyloxy carbonyls amino acids has been devised.
Abstract: A new method for the preparation of t-butyloxycarbonyl amino acids and p-methoxybenzyloxycarbonyl amino acids has been devised. The former was obtained in satisfactory yields from amino acids and t-butyl S-4,6-dimethylpyrimid-2-ylthiocarbonate prepared from t-butyl alcohol and (4,6-dimethylpyrimid-2-ylthio)corbonyl chloride in dry pyridine, and the latter was also obtained from amino acids and p-methoxybenzyl S-4,6-dimethylpyrimid-2-ylthiocarbonate from p-methoxybenzyl alcohol and (S-4,6-dimethylpyrimid-2-ylthio)carbonyl chloride. These t-butyloxycarbonylation and p-methoxybenzyloxycarbonylation of amino acids are more convenient than the usual methods.
116 citations
TL;DR: In this paper, the transformation of vaterite to calcite was investigated systematically and the transition temperature and the energetics of the transformation were determined from differential thermal curves, and the variations of lattice constants and crystallite size, accompanying the transformation, were studied by X-ray diffractometry.
Abstract: The transformation of vaterite to calcite was investigated systematically. The transition temperature and the energetics of the transformation were determined from differential thermal curves. The variations of lattice constants and crystallite size, accompanying the transformation were studied by X-ray diffractometry. The kinetics of transformation were investigated in the temperature range 460–490°C. The kinetic data were analysed with the help of three separate solid-state models.
115 citations
TL;DR: Arylation of propylene, ethylene, styrene, and methyl acrylate with iodobenzene was found to be catalyzed by metallic palladium in methanol to give methylstyrene and methyl cinnamate, respectively as discussed by the authors.
Abstract: Arylation of propylene, ethylene, styrene, and methyl acrylate with iodobenzene was found to be catalyzed by metallic palladium in methanol to give methylstyrene, styrene, t-stilbene, and methyl cinnamate, respectively. Their yields and selectivities increased significantly by the addition of excess potassium acetate as an acceptor of hydriodic acid formed. The course of catalytic reaction is discussed in terms of the oxidative addition of iodobenzene to a palladium complex of low oxidation state.
113 citations
105 citations
TL;DR: In this paper, the binding energies of Fe2p3µ2 and Ols electrons were measured during the course of reactions and their variation was discussed in terms of the positive and negative charges of the iron and oxygen of the surface oxide formed, respectively, assuming a simple charge-chemical shift relation.
Abstract: Reactions of evaporated iron with O2 and H2O have been investigated by X-ray photoelectron spectroscopy. Binding energies of Fe2p3⁄2 and Ols electrons were measured during the course of reactions and their variation was discussed in terms of the positive and negative charges of the iron and oxygen of the surface oxide formed, respectively, assuming a simple charge-chemical shift relation. They are compared with the binding energies of the Ols in SiO2 Al2O3, Fe2O3, Cd(OH)2, KOH, and Ni(OH)2 and those of Fe2p3⁄2 in various iron compounds High reactivity of the surface oxide with H2O and the resulting hydroxyl group formation were observed. A rough estimation of the Fe to O atomic ratio of the surface oxide was also carried out from the ratio of the Fe and O peak areas.
96 citations
TL;DR: The crystal structures of methyl bromide and methyl iodide have been determined by the X-ray diffraction method at about −120°C and about −80°C respectively as discussed by the authors.
Abstract: The crystal structures of methyl bromide and methyl iodide have been determined by the X-ray diffraction method at about −120°C and about −80°C respectively. Both the crystals are isomorphous, with orthorhombic space group D2h16–Pnma. Unit cells containing four molecules have the dimensions: a=4.474(1), b=6.420(2), and c=9.150(1) A for methyl bromide, and: a=4.597(2), b=6.987(1), and c=10.117(1) A for methyl iodide. These structures are quite different from that of methyl chloride, which has a symmetry of C2v12–Cmc21. In the three crystals, all the molecules are found on the mirror planes; the difference lies in the mutual orientations of the molecules.
TL;DR: In this paper, the authors measured the heat capacities of isopropylbenzene with an adiabatic calorimeter for the crystal from 14 to 177.13 K (Tm), for the glassy state from 14-126 K (glass transition temperature: Tg) and for the liquid from Tg to 313 K, with a sample of 99.93% purity.
Abstract: The heat capacities of isopropylbenzene were measured with an adiabatic calorimeter for the crystal from 14 to 177.13 K (Tm), for the glassy state from 14 to around 126 K (glass transition temperature: Tg) and for the liquid from Tg to 313 K, with a sample of 99.93% purity. The heat and entropy of fusion were found to be 7326 J mol−1 and 41.36 J K−1 mol−1, respectively. Based on these data, a set of thermodynamic functions are tabulated at rounded temperatures. In addition to the primary glass transition phenomenon, a secondary enthalpy relaxation as well as a step-like heat capacity anomaly was observed at around 70 K. These facts were discussed in correlation with the β-relaxation already observed by dielectric measurement. Gonfigurational entropies of the supercooled liquid and of the glassy state were calculated to investigate a relation with relaxational properties. The agreement is found between the temperatures where catastrophe occurs in viscosity (T0), and where the configurational entropy vanish...
TL;DR: In this paper, the solubility of sulfur in Na2O-SiO2 melts was investigated by varying the oxygen partial pressure at 1100, 1250, and 1300 °C, and the results at 1100 °C are complicated, for the equilibrium state within the gas phase is not established.
Abstract: The solubility of sulfur in Na2O–SiO2 melts with the Na2O/SiO2 molar ratios of 1/3, 1/2, and 1/1 was investigated by varying the oxygen partial pressure at 1100, 1250, and 1300 °C The results at 1100 °C are complicated, for the equilibrium state within the gas phase is not established From the experiments at 1250 and 1300 °C, the following conclusions are reached: (1) When the temperature and the Na2O/SiO2 ratio in the melt are constant, the solubility of sulfur increases with an increase of the total amount of sulfur in the gas phase (2) When the temperature, the Na2O/SiO2 ratio, and the total amount of sulfur in the gas phase are constant, the solubility of sulfur shows its minimum at a specific oxygen partial pressure; at higher oxygen partial pressures, the sulfur dissolves in the melts mostly as sulfate, while at lower oxygen partial pressures, the sulfur dissolves mostly as sulfide (3) When the temperature and the total amount of sulfur in the gas phase are constant, the solubility rises greatly
TL;DR: In this paper, a series of multilayered cyclophanes up to sixfold were synthesized by 1,6-Hofmann elimination method by cross-breeding pyrolysis of mixed quaternary ammonium hydroxides.
Abstract: A series of multilayered cyclophanes up to sixfold were synthesized by 1,6-Hofmann elimination method. Odd layered and some dissymmetric ones were derived by means of cross-breeding pyrolysis of mixed quaternary ammonium hydroxides. The electronic spectra, absorption, emission, and CT absorption of charge-transfer complexes, of these cyclophanes exhibited remarkable transannular π-electronic interaction among chromophores closely stacked by methylene bridges. The interaction is increased eminently when the layer is varied from single to quadruple, but becomes less effective from quadruple to fivefold and no longer appreciable for more than fivefold one.
TL;DR: In this article, the factors which influence the crystallization of rare earth carbonates were studied, and the crystal parameters, compositions, and factors concerning the formations of various carbonates, such as lanthanite-type Ln2(CO3)3·8H2O(Ln=La, Ce), tengeritetype Ln 2(CO 3 )3·nH 2O (Ln = Nd, Sm, Gd, Dy, Ho, Er, and Y, n=2−3), monoxocarbonate-
Abstract: The factors which influence the crystallization of rare earth carbonates were studied. Crystalline rare earth carbonates were precipitated at various temperatures from aqueous solutions by using sodium carbonate, sodium bicarbonate, trichloroacetic acid, and urea as precipitants. The crystal parameters, compositions, and factors concerning the formations of various carbonates, such as lanthanite-type Ln2(CO3)3·8H2O(Ln=La, Ce), tengeritetype Ln2(CO3)3·nH2O(Ln=Nd, Sm, Gd, Dy, Ho, Er, and Y, n=2–3), monoxocarbonate-type Ln2O(CO3)2·nH2O(Ln=La, Ce, Nd, and Sm, n=1–2) and a hydrated double carbonate of rare earth and sodium (rare earth= La, Ce, Nd, Sm, Gd, Dy, and Y) were determined by chemical analysis and X-ray powder diffractometry.
TL;DR: The crystal structure of tin(II) chloride dihydrate, SnCl2·2H2O has been determined by a single crystal X-ray diffractometer technique as discussed by the authors.
Abstract: The crystal structure of tin(II) chloride dihydrate, SnCl2·2H2O has been redetermined by a single crystal X-ray diffractometer technique. The crystal is monoclinic, space group P21⁄c with a=9.313, b=7.250, c=8.970 A, β=114°55′ and Z=4. The structure was solved by three-dimensional Patterson and electron density syntheses. An anisotropic least-squares refinement, based on 1695 independent reflections gave an R value of 0.04. The tin(II) atom forms a pyramidal complex with two chlorine atoms and one oxygen atom; the bond lengths in the pyramid are Sn–O, 2.33 and Sn–Cl, 2.50 and 2.56 A and the bond angles are 86.9, 85.0, and 87.9°. These results support a view that the bonding in dichloroaquotin(II) complex is considerably ionic in character. This crystal consists of double layers of the aquocomplex, SnCl2·(OH2), parallel to (100) with intervening layers of the second water molecules. Both kinds of the water molecules are linked together by hydrogen bonds of 2.74, 2.79, and 2.80 A into two-dimensional networ...
TL;DR: In this article, the photoelectron spectra of higher alkyl amines and alcohols (Me, Et, n- and i-Pr, and n-Bu) have been measured with the 584 A line of helium.
Abstract: Photoelectron spectra of higher alkyl amines and alcohols (Me, Et, n- and i-Pr, and n-Bu) have been measured with the 584 A line of helium. Seven photoelectron bands corresponding to p-type MO’s we...
TL;DR: In this paper, high-resolution photoelectron spectra of alkyl halides RX (R=ethyl, n-propyl, and n-butyl; X=C1, Br, and I) were measured with the 584 A line of helium.
Abstract: High-resolution photoelectron spectra of alkyl halides RX (R=ethyl, n-propyl, and n-butyl; X=C1, Br, and I) were measured with the 584 A line of helium. In the region below about 17 eV, six bands were observed for each of the ethyl halides, eight bands for each of the n-propyl halides, and ten bands for each of the n-butyl halides. All the observed vertical ionization energies were plotted against Pauling’s electronegativity of the halogen atom, indicating that there are approximate linear relationships. Assuming Koopmans’ theorem, total and partial sums of experimental orbital energies were calculated using the observed ionization energies for the individual alkyl halides and found to be well reproduced by calculating the sums of empirical orbital-energy values for several localized orbitals such as n(X.), n′(X), σ(C–X), σ(C–C), π(CH3), π′(CH3), and π(CH2). From a comparison of the experimental and calculated partial orbital-energy sums, assignments of the photoelectron bands to the localized molecular o...
TL;DR: In this article, the theoretical scattering factors currently used have shown satisfactory conformity to the observed scattering intensity, with the following distance parameters: rg(Hg-C)=2.083±0.005 A, rg(hg-Hg…H)= 2.71± 0.02 A, and rg(C−H)=1.106 A (assumed).
Abstract: Electron scattering by dimethylmercury has been studied for 42 keV electrons. The theoretical scattering factors currently used have shown satisfactory conformity to the observed scattering intensity, with the following distance parameters: rg(Hg–C)=2.083±0.005 A, rg(Hg…H)=2.71±0.02 A, and rg(C–H)=1.106 A (assumed). A comparison of the background functions has revealed that the scattering factors based on the relativistic Hartree-Fock-Slater potential are better than those based on the Thomas-Fermi-Dirac and Thomas-Fermi potentials. The zero-point average distance determined from the spectroscopic data has shown significant inconsistency with the diffraction result. The diffraction value is shorter than the spectroscopic one by 0.015 A.
TL;DR: In this article, an intramolecular two stage dehydrogenation process is proposed for coupling of diphenyl ether and diphenylene oxide with coupling dimers, and yields and isomer distributions are attributed to reaction variables such as temperature, additives, and the nature of the substituent on a benzene ring.
Abstract: The oxidative coupling reaction of aromatic compounds proceeds catalytically with palladium salt under oxygen pressure. Yields and isomer distributions are attributed to the reaction variables such as temperature, additives, and the nature of the substituent on a benzene ring. Naphthalene was converted mainly into 1-substituted products and o-xylene into 4-substituted products. The coupling of diphenyl ether afforded diphenylene oxide with coupling dimers. An intramolecular two stage dehydrogenation process is proposed.
TL;DR: In this paper, extra absorption spectra appeared when 7,7,8,8-tetracyanoquinodimethane (TCNQ) was solubilized into surfactant organic solvent solutions above the critical micelle concentration.
Abstract: Extra absorption spectra appeared when 7,7,8,8-tetracyanoquinodimethane (TCNQ) was solubilized into surfactant organic solvent solutions above the critical micelle concentration (CMC). It was found also that extra absorption spectra appeared when iodine was solubilized into surfactant organic solvent solutions above the CMC. In the former case, the extra absorption spectra are attributed to TCNQ anion radical salts formed between TCNQ and the surfactants. In the latter, the extra absorption spectra are due to charge-transfer interactions of iodine with the surfactants. The intensity of the absorption bands increased with the concentrations of the surfactant. The values of the CMC of the surfactants were determined from this spectral change. The CMC values obtained by the TCNQ solubilization method were larger than those obtained by the iodine solubilization technique. The difference in the CMC between the two methods was interpreted in terms of the difference in solubility and chargetransfer power to the ...
TL;DR: The static magnetic susceptibility and the ESR spectra from 1.6 to 300 K have been measured on a powder sample of the titled free radical and the broad maximum in the susceptibility which indicates an antiferromagnetic interaction has been observed at 6.9 K as discussed by the authors.
Abstract: The static magnetic susceptibility and the ESR spectra from 1.6 to 300 K have been measured on a powder sample of the titled free radical. The broad maximum in the susceptibility which indicates an antiferromagnetic interaction has been observed at 6.9 K. The broadening of the ESR absorption line and the shift of the g-value have been found in the temperature region below Tmax, in which the susceptibility reached its round maximum. There appeared anomalies in the slope of the susceptibility, the linewidth, and the g-value versus temperature curves in the vicinity of 1.7 K. These anomalies may imply a magnetic-phase transition from the short-range ordered state to the long-range ordered state at about 1.7 K. The existence of a ferromagnetic interaction between the magnetic chains in the triphenylverdazyl radical solid is discussed on the basis of the susceptibility, the spin distribution, and the crystal structure. It is understood qualitatively that the radical with a negative spin density has a latent fe...
TL;DR: In this article, the solubilization behavior of the complexes composed of a surfactant and polyethylene glycol (PEG) toward an oil-soluble dye, Yellow OB, has been studied in relation to the degree of polymerizatio...
Abstract: The solubilization behavior of the complexes composed of a surfactant and polyethylene glycol (PEG) toward an oil-soluble dye, Yellow OB, has been studied in relation to the degree of polymerizatio...
TL;DR: In this paper, a new series of binuclear copper(II) complexes, [Fsal(=NenNR2)2Cu2X]2+ (R=Me and Et, X=Cl, Br, and OH), were synthesized, where Fsal( = NenNR 2)2 indicates the Schiff base prepared from 2,6diformyl-4-methylphenol and N,N-dialkylethylenediamine (alkyl=methyl(Me) and ethyl(Et)).
Abstract: A new series of binuclear copper(II) complexes, [Fsal(=NenNR2)2Cu2X]2+ (R=Me and Et, X=Cl, Br, and OH), were synthesized, where Fsal(=NenNR2)2 indicates the Schiff base prepared from 2,6-diformyl-4-methylphenol and N,N-dialkylethylenediamine (alkyl=methyl(Me) and ethyl(Et)). Two copper(II) ions are connected with the phenolic oxygen and X. The complexes obtained were characterized by elemental analyses, infrared and visible spectra, molar conductivities in methanol, ESR spectra and magnetic susceptibilities. It was found that the stability of the complexes decreases in the order X=OH>>Br>Cl. It was concluded from cryomagnetic measurements that the effect of the bridging group X on spin-coupling decreases in the order OH>>Br>Cl.
TL;DR: The structure parameters of tetramethyltin have been determined by gas-phase electron diffraction to be as follows: rg(Sn−C)=2.1436±0.0030 A, rg(sn−H)=1.7642±0.0125 A, and l(C-H)=0.1179±0 as mentioned in this paper.
Abstract: The structure parameters of tetramethyltin have been determined by gas-phase electron diffraction to be as follows: rg(Sn–C)=2.1436±0.0030 A, rg(Sn···H)=2.7642±0.0125 A, rg(C–H)=1.1179±0.0090 A, l(Sn–C)=0.0496±0.0098 A, and l(Sn···H)=0.1532±0.0132 A. The experimental molecular intensity has been well reproduced by the molecular model in which the methyl groups are rotating freely, or nearly freely. The scattering factors, based upon the relativistic Hartree-Fock-Slater or the Hartree-Fock atomic potential, have given a theoretical background in better agreement with the experimental one and have led to a more reasonable Sn–C mean amplitude than did the scattering factors based upon the Thomas-Fermi-Dirac or the Thomas-Fermi atomic potential.
TL;DR: In this paper, the possibilities of ground state complex and excimer formation in various liquid solvents were examined thoroughly, and the results of the self-complexion of p-(N,N-dimethylamino)-benzonitrile and its hetero-complex formation with benzonitriles in cyclohexane matrix were studied in detail.
Abstract: Electrostatic self-complex formation of p-(N,N-dimethylamino)-benzonitrile and its hetero-complex formation with benzonitrile in cyclohexane matrix were studied in detail. The possibilities of ground state complex and excimer formation in various liquid solvents were examined thoroughly.
TL;DR: In this paper, the depolarization of the fluorescence emitted from a dye solubilized in the micelle was measured over a wide concentration range of sodium dodecyl sulfate (SDS).
Abstract: The depolarization of the fluorescence emitted from a dye solubilized in the micelle was measured over a wide concentration range of sodium dodecyl sulfate (SDS) The polarization of the fluorescence showed an abrupt increase at the 1st CMC and at about 70 mM of SDS; the latter agrees very closely with the 2nd CMC revealed by conductivity and viscosity measurements This phenomenon implies that there is a certain change in the micelle structure at the 2nd CMC The micellar size was calculated from the fluorescence depolarization data using Perrin’s equation The results showed that: (1) the micellar volume below the 2nd CMC is in good agreement with that determined by light-scattering, (2) the micellar volume gradually increases with an increase in the concentration of SDS, and (3) the micellar volume increases abruptly at the 2nd CMC
TL;DR: From the temperature dependency of the adiabatic compressibility in aqueous systems of nonelectrolytes, established by ultrasonic measurements, it is concluded that structural units to be termed "liquid clathrate hydrates" do exist for various systems, and the concentration of the zero temperature coefficient of adiabilistic compressibility representing the composition-mole-ratio, rcβ(water/solute), for these hydrates with rcβ=7.2
Abstract: From the temperature dependency of the adiabatic compressibility in aqueous systems of nonelectrolytes, established by ultrasonic measurements, it is concluded that structural units to be termed “liquid clathrate hydrates” do exist for various systems, the concentration of the zero temperature coefficient of adiabatic compressibility representing the composition-mole-ratio, rcβ(water/solute), for these hydrates. Hydrates with rcβ=7.2⁄3 (for methanol, formamide, and urea) and 17 (for acetone and ethanol) correspond to the solid clathrate hydrates of Structures I and II respectively, while those with rcβ=24, 28, 32, etc, can be explained on the basis of appropriate assumptions.
TL;DR: In this paper, the origin of near-ultraviolet absorption in binuclear copper(II) complexes was investigated and the absorption was attributed to charge transfer transitions from nonbonding orbitals of bridging oxygen atoms to the vacant metal d-orbital.
Abstract: Elucidation of the origin of near-ultraviolet absorption believed to be characteristic of binuclear copper(II) complexes was attempted. The absorption was attributed to charge transfer transitions from nonbonding orbitals of bridging oxygen atoms to the vacant metal d-orbital. Appearance of the band in the near-ultraviolet region was interpreted in terms of the red-shift due to the decreasing s-character of the nonbonding orbitals enforced by the steric requirement of the complex. On this basis, the spectra of dialkoxo- or dihydroxo- bridged complexes and of copper alkanoates can consistently be explained.