Koyo Aida

Infra-red absorption spectra of charge-transfer complexes of trimethylamine: (CH3)3N·I2, (CH3)3N·IBr and (CH3)3N·ICl

Abstract The infra-red spectra of (CH 3 ) 3 N·IX, where X is I, Br or Cl, have been studied in the 4000-60 cm −1 region. Assigmnents of the fundamentals have been made.

Vibrational spectra of (CD3)3MX and normal coordinate calculations for (CH3)3MX and (CD3)3MX (M = Ge, Sn; X = Cl, Br)

Abstract IR (4000-30 cm−1) and Raman (4000-0 cm−1) spectra of (CH3)3MX (M = Ge, Sn; X = Cl, Br) have been recorded, together with those of (CD3)3MX. By assuming the C3v, molecular symmetry, all the active fundamentals except an internal torsion have been assigned and normal coordinate calculations have been carried out to confirm the proposed assignments by a symmetry force field for (CH3)3MX and (CD3)3MX.

Far-infrared spectra of charge-transfer complexes between IX (X = I, Br, Cl) and some organic sulfides

Abstract Far-i.r. spectra of charge-transfer complexes of IX (X = I, Br, Cl) with some organic sulfides, including chloromethyl- and dichloromethyl-methyl sulfide, have been measured in the region 400-30 cm−1 in polyethylene matrices. Assignments for the modified I—X stretching vibrations have been proposed. The intermolecular S—I stretching vibration has also been tentatively assigned for a few sulfide-I2 and -ICI complexes, for which the force constants have been calculated under the assumption of a linear triatornic model.

IR spectra of charge-transfer complexes between IX(X = Cl, Br) and aminopyridines

Abstract IR and far-IR spectra of charge-transfer (CT) complexes between IX(X = Cl, Br) and 2-, 3- and 4-aminopyridines (2AP, 3AP and 4AP) have been measured. It is concluded that the ring nitrogen, not the amino nitrogen, is involved in complex formation. Assignments for the modified interhalogen IX stretching and the intermolecular NI stretching vibrations have been proposed. The force constants for these vibrations were calculated under the assumption of a linear triatomic model.

Infra-red absorption spectra and structure of biuret-hydrogen peroxide complexes

Abstract Two complexes of biuret and hydrogen peroxide, (C 2 H 5 N 3 O 2 ) 5 ·H 2 O 2 and (C 2 H 5 N 3 O 2 ) 5 · (H 2 O 2 ) 2 , have been prepared. The infrared absorption spectra and the X-ray diffraction patterns of these complexes are quite similar to those of biuret hydrate. Consequently, it has been concluded that the biuret molecules in these complexes have the trans configuration and make up inclusion compounds as is the case in biuret hydrate. The differences between complexes of urea-hydrogen peroxide and biuret-hydrogen peroxide are discussed.

Far-i.r. spectra of charge-transfer complexes between IX (X = Cl, Br) and some pyridine and quinoline bases

Abstract Far-i.r. spectra of charge-transfer (CT) complexes of IX (X = Cl, Br) with pyridine, quinoline and their derivatives have been measured in solids. Assignments for the intermolecular NI stretching and the modified IX stretching vibrations are proposed. The force constants for these vibrations have been calculated assuming a linear triatomic model, putting a donor molecule as a point mass. The relationship between the relative decrease in the IX stretching force constants and the p K a values of donor molecules is discussed.

Vibrational spectra of ICl2− and IBr2− ions in aminopyridinium trihalides

IR and Raman spectra for iodine dichlorides and iodine dibromides of 2-, 3- and 4-aminopyridines (2AP, 3AP and 4AP) in solids have been measured, together with those for pyridine (Py). Raman spectra in methanol solutions have also been obtained. Although each AP molecule has two nitrogen atoms each having a lone pair of electrons, it is found that protonation occurs at the ring nitrogen atom. It is concluded that two configurations for ICl2− ion, symmetric and asymmetric, coexist in solids as well as in solution. For IBr2−, two configurations coexist in solids, while only asymmetric configuration exists in solution.

Normal coordinate analyses of trimethylphosphine oxide, trimethylphosphine sulfide and trimethylphosphine selenide

Abstract The infrared and Raman spectra of trimethylphosphine oxide, trimethylphosphine sulfide, trimethylphosphine selenide and their perdeuterated analogues have been recorded. The fundamentals (except for the internal torsion) have been assigned for each molecule. Normal coordinate calculations were carried out by a symmetry force field to confirm the proposed assignments, and to derive the PO, PS and PSe stretching force constants.

Hydrogen bonding between phenol and alkyl thiocyanates

Abstract Hydrogen bonding between phenol and alkyl thiocyanates, dissolved in carbon tetrachloride, has been studied by means of infrared spectroscopy. The appearance of a new OH stretching vibration band, about 150 cm −1 lower than that of free phenol, clearly indicates the formation of the hydrogen bond in this system. Using an empirical relation between the concentration of phenol and the intensity of the free OH stretching vibration band, the equilibrium constants have been determined over the temperature range 20–50°C. From these, the heats of bonding (2.9–4.1 kcal mol ) and the entropy changes (7–11 e.u.) have been obtained.

Vibrational spectra and normal coordinate calculations for trimethylselenonium-d0 and -d9 ions and dimethyl selenide-d0, -d6

Abstract The i.r. (4000-30 cm −1 ) and Raman (4000-0 cm −1 ) spectra of trimethylselenonium iodide and dimethyl selenide have been obtained, together with those of their deuterated analogues. All the active fundamentals of the trimethylselenonium ion have been assigned, assuming C 3ν molecular symmetry. Normal coordinate calculations have been carried out for the trimethyl-selenonium ion and dimethyl selenide and the SeC force constants of both the compounds are compared, including those of other corresponding chalcogenides.