Isao Kanesaka

Vibrational spectra and structures of zinc carboxylates I. Zinc acetate dihydrate

Abstract The crystal structure of zinc acetate dihydrate was re-refined by X-ray diffraction analysis of the single crystal. The monoclinic cell dimensions were revised as a=14.394 (3), b=5.330 (2), c=10.962 (3) A and β=99.8 (2)° with Z=4. The bond distances and bond angles were also refined. Based on the structure, a normal mode analysis was made and the valence force constants were determined. Precise spectral assignments were made. Based on the assignments and the structure, the relation between the coordination forms and the vibrational frequencies of the carboxylate antisymmetric stretch and the symmetric stretch were discussed. In order to identify the coordination form of the carboxylate group from the vibrational frequencies, we propose the importance of other carboxylate modes other than the stretches.

Vibrational spectra and structures of zinc carboxylates II. Anhydrous zinc acetate and zinc stearate

Abstract A normal mode analysis was carried out for a monoclinic anhydrous zinc acetate crystal in which the acetate groups had bridging bidentate coordination forms, and spectral assignments were made. Based on the assignments, a relation between the coordination structure of the carboxylate groups around the zinc atom and the vibrational frequencies of the carboxylate rocking mode was found. This relation was applied to zinc stearate to determine its coordination form, and we found that zinc stearate had a bridging bidentate form.

Infrared spectra of addition compounds of hydrogen and deuterium cyanides with some inorganic chlorides

Abstract The infrared spectra of addition compounds, (XCN) m · YCl n in which X is H or D, Y is B, Ti or Sb, m is 1 or 2 and n is 3, 4 or 6, have been measured in the region from 4000 to 250 cm −1 . The observed spectra of XCN · BCl 3 and XCN · SbCl 5 have been assigned on the basis of C 3 v , and G 4 v symmetry, respectively. A normal co-ordinate analysis has been performed for XCN · BCl 3 , and the isotopic effect upon the normal frequencies and the co-ordination effect upon the shift of vibrational frequencies of the parent molecules have been discussed.

The methyl torsion in toluene (h8, d8) and nitromethane (h3, d3) in the polycrystalline state

The Raman spectra of toluene and nitromethane at about −150 °C were observed in the region of 10–250 cm−1. In toluene‐h8 two weak and sharp bands observed at 77 and 115 cm−1 were assigned to the CH3 torsion. In toluene‐d8 the CD3 torsion was not observed distinctly. The assignment was confirmed by the calculation of the torsional energy levels on the basis of the C2v symmetry by the finite element method. The potential function was assumed to be Σ1/2Vn(1−cosnβ) (n=2, 6, and 12). The best fit was obtained when V2, V6, and V12 were 28, 99, and −42 cm−1, respectively, and further confirmed that the other structures observed at 106 and 94 cm−1 could be also assigned to the CH3 torsion. In nitromethane‐h3 or ‐d3 a very weak and broad band observed at 148 or 132 cm−1, respectively, was assigned to the methyl torsion. In the process of the adjustment of the potential constants it was found that V3 was important. The best fit was obtained when V3, V6, and V12 were 210, 150, and 30 cm−1, respectively. This shows t...

Infrared spectra of addition compounds of cyanogen halides with some inorganic halides

Abstract The infrared spectra of addition compounds of cyanogen halides (ClCN, BrCN) with inorganic halides (SbCl 5 , TiCl 4 , AlCl 3 , AlBr 3 ) have been measured in the region from 4000 to 250 cm −1 . The displacement of bands by the formation of a co-ordination bond and the appearance of metal-to-nitrogen stretching vibrations indicate the acceptance of a lone pair of electrons from the nitrogen atom of cyanogen halides in virtue of Lewis acid. The bands observed in the addition compounds of cyanogen halides (ClCN, BrCN) with SbCl 5 have been assigned on the basis of C 4 v symmetry, and those with TiCl 4 of D 4h symmetry. The bands observed in the addition compounds of ClCN with AlCl 3 and of BrCN with AlBr 3 have been assigned on the basis of C 3 v symmetry. The displacement of CN stretching frequency has also been studied for the addition compounds of ClCN with inorganic halides (AlCl 3 , TiCl 4 ) in the solution of SOCl 2 or POCl 3 .

Stability of ZrCo and ZrNi to Heat Cycles in Hydrogen Atmosphere

ABSTRACTThe stability of ZrNi and ZrCo to heat cycles in hydrogen atmosphere was studied through changes in absorption-desorption characteristics and in crystallo-graphic structures. ZrCo easily lost its absorption-desorption capacity of hydrogen below 30 heat cycles between room temperature and a given temperature in a range of 400 ∼600 °C. X-ray diffraction analysis showed that ZrCoH3 initially formed decomposed to ZrH2+ ZrCo2. On the other hand, ZrNi was more durable than ZrCo to the similar heat cycles. But, it was found that the absorption-desorption characteristics was degraded by heat cycles over 500. The X-ray analysis showed that ZrNi also disproportionated to ZrH2 and ZrNi3. The difference in the stabilities between the two materials appears to be due to the difference in crystallographic nature upon formation of the respective hydrides.

VIBRATIONAL STUDY OF HYDROGEN BONDS AND STRUCTURE OF TRIS(HYDROXYMETHYL)AMINOMETHANE

The vibrational spectra of tris(hydroxymethyl)aminomethane (THAM) were observed at various temperatures and the polarized Raman spectra at room temperature. The three types of O–H stretch indicate that the structure of THAM consists of a chain rather than a layer structure. Some structures found in the strong hydrogen bond at 1920 cm-1 in deuterated THAM are attributed to the Fermi resonance. One of C–O(H) torsions was found at 1055 cm-1 and some new assignments are proposed for the C–O stretches, the C–C stretch and C–O(H) torsions. Structural change of the first order was found at 190 K in THAM, which is ascribed to ordering of C—O1(H) groups, which form weak hydrogen bonds.

Raman Intensity of Dioxane and Piperazine by the Modified Many‐Body Model

The vibrational Raman intensities of dioxane and piperazine were analysed on the basis of the modified many-body model, using atomic polarizabilities obtained from many-body interactions among induced dipoles on atoms. The polarized Raman spectrum of dioxane was analysed satisfactorily, but not the depolarized spectrum. It is concluded that the atomic polarizability used is suitable for explaining Raman intensities, especially for bending vibrations. Only bond stretch intensity parameters are needed in the bond polarizability description. The vibrational assignments of piperazine were also treated using the same force field and the intensity parameters as in dioxane, adding some force constants for the NH groups.

Infrared intensity and morphology of 1-monolaurin–water systems

The infrared spectra for some metastable states in 1-monolaurin water systems were observed at room temperature, where the relative intensity of bands due to paraffin chains changed considerably, especially in the CH2 rockings, which disappear in some cases. It is considered that the spectral changes result from the morphology change on going from the crystal to the liquid crystal, smectic B phase, so-called gel phase, which consists of the lipid bilayers with ordered paraffin chains alternating with water layers. The model for explaining the intensity change is proposed on the basis of the interaction among oscillating dipoles.

MOLECULAR DYNAMICS SIMULATION OF INFRARED SPECTRA FOR POTASSIUM PALMITATE B-FORM CRYSTAL

The intra‐ and intermolecular potentials of potassium palmitate B‐form crystal were estimated by a normal mode analysis and a molecular dynamics simulation. Based on these potentials, we calculated the time history of the dipolemoment in the nine unit cells (3a×3b) containing 18 molecules and obtained the polarized infrared spectra by a Fourier transformation. The frequencies and the intensities of the intense bands agreed well with the observed ones, and were consistent with the crystal structure.The intra‐ and intermolecular potentials of potassium palmitate B‐form crystal were estimated by a normal mode analysis and a molecular dynamics simulation. Based on these potentials, we calculated the time history of the dipolemoment in the nine unit cells (3a×3b) containing 18 molecules and obtained the polarized infrared spectra by a Fourier transformation. The frequencies and the intensities of the intense bands agreed well with the observed ones, and were consistent with the crystal structure.