Kiyoyasu Kawai

The vibrational spectra of phthalic anhydride

Abstract The IR and Raman spectra of phthalic anhydride have been reported for the polycrystalline sample and the polarized Raman spectrum for the molten sample. The observed frequencies have been assigned tentatively to the C2v molecular symmetry and a normal coordinate analysis has been carried out for a modified valence force field.

Vibrational spectrum and force constants of the monochlorochromate ion

Abstract The vibrational spectrum of the ion (CrO3Cl)− is reported. The Raman spectra were obtained in the red region of the spectrum by excitation with the helium radiations 5875.6 and 6678.2 A, the infra-red absorption spectrum was investigated over the range 10–32 μ. The spectrum is in full agreement with the expected C3v -symmetry of the ion and the observed frequencies have been assigned under this point group. A normal co-ordinate treatment based upon Wilsons -FG-matrix method and a simplified valence force field has been carried out and force constants have been calculated. The stretching frequencies of the ion and the related valence force constants are compared with those of other hexavalent chromium compounds, previously reported by the authors.

The infrared and Raman spectra of pyromellitic dianhydride

Abstract The infrared and Raman spectra of solid state samples of pyromellitic dianhydride have been measured. The infrared—Raman mutual exclusion rule has been observed and the frequencies have been tentatively assigned on the basis of D 2h symmetry. The values of the CO and skeletal ring stretching frequencies have been interpreted in terms of a conjugated π-system.

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 .

The energy levels of the CH3 asymmetric bending vibrations of toluene

The energy levels of the CH3 asymmetric bending vibrations of toluene were calculated by the use of a finite element method for the two dimensional vibrational Schrodinger equation on the basis of a C 2v symmetry of the molecule. The totally symmetric CH3 torsion was only considered and some boundary conditions were used for the CH3 asymmetric bending vibrations. The splittings of the energy levels were examined in relation to the interaction potential V 2 or V 6′ with the CH3 asymmetric bending and the CH3 torsional coordinates. The ir spectrum was observed in the region of those vibrations at room temperature and the Raman experiments at about −140 °C. The observed bands were assigned by comparing them with the calculated levels.

Structure and properties of iron(III) 1,3-propanediaminetetraacetate complex in aqueous solutions

Abstract The structure of iron(III) 1,3-propanediaminetetraacetate (1,3-pdta) in aqueous solutions was studied on the basis of Raman spectroscopy, nuclear magnetic relaxation, and pH titration. It has been found that, in aqueous solution, Fe(1,3-pdta)− exists in a normal sexidentate hexacoordinate geometry. The six-membered chelate ring formed by the diamine moiety of the 1,3-pdta ligand does not adopt a skew-boat conformation having C2 symmetry (as found in sodium salt crystals) hut a twist-boat one having no C2 symmetry (as in the lithium salt crystals). Although edta complexes of iron(III) form a dimeric complex in slightly alkaline solutions, the 1,3-pdta complex of Fe(III) does not show such a tendency. The 1,3-pdta complex is stable only in the pH region of 2–7.5; the corresponding edta complex is stable even in a strongly acidic solution.

The vibrational spectrum of NaI · 2X2O (X = H OR D)

Abstract The Raman spectrum of NaI · 2X2O at room temperature and 77 K is reported. The assignment was carried out carefully so as to clarify differences in the spectra between two types of water molecules, whose bonding character is similar, on the basis of a normal coordinate anaysis. It is found that OX2 librations relate closely to NaO coordination bond rather than a hydrogen bond.

The infra-red spectrum of [Co(en)3]Cl3·3T2O (en: ethylenediamine)

Abstract The infra-red spectrum of [Co(en) 3 ]Cl 3 ·3T 2 O has been observed over a period of 5 months. The spectrum changes considerably even in 2 days after preparation of the hydrate, revealing quite different features from the parent. Initially some bands due to the NH 2 group disappear, while new bands appear. These are explained in terms of a change in bonding character or as an interaction between the complex ion and the chloride anion in the crystal. Subsequently, the bands due to ethylenediamine decrease in intensity and almost vanish, while additional new bands appear. The new bands are explained in terms of ammine complexes. It is proposed that a decomposition reaction of en → 2NH 3 + HCCH takes place through intermediates such as vinylamine and so on. After one month the spectrum still changes slowly with further new bands due to a HT exchange reaction.