Deuterated Form Research Articles

Hydrogen bond studies. 71. Ab initio calculation of the vibrational structure and equilibrium geometry in HF −2 and DF −2

MO LCAO SCF calculations have been performed to investigate the molecular astructure and vibrational spectrum of the bifluoride ion in its normal and deuterated form. The potential energy for nuclear motions has been evaluated as a function of the molecular degrees of freedom, taking only linear geometries into account. The vibrational Schrödinger equation has been solved by expanding the vibrational part of the total wavefunction as a sum of products of linear harmonic-oscillator eigenfunctions. The calculated properties are in good agreement with experiments, and even the minute effects of deuteration are well reproduced.

A new method for the determination of biological quarternary structure by neutron scattering.

Determination of quaternary structure by neutron scattering is proposed. The method gives the identity and relative spatial position of each component of a complex, provided that the complex can be obtained in deuterated form and can be reconstituted from its separated parts. If two components are rich in hydrogen and if the rest of the complex is deuterated, the contrast in scattering power permits the measurement of the separation of the pair from an interference cross term. The structure is obtained by triangulation from a set of measured pair separations.

Electron Spin Resonance Study of X-Irradiated Single Crystals of Semicarbazide

Free radicals of the structure ${\rm H}_{2}{\rm N}\text{-}{\rm CONH}\dot{{\rm N}}{\rm H}$ have been identified from their esr spectra in x-irradiated single crystals of semicarbazide and the deuterated form, ${\rm ND}_{2}{\rm CONDND}_{2}$. Principal values for the hyperfine coupling constants and their direction cosines with respect to the reference axes are given. The results indicate that the unpaired electron is mainly localized in a π-type orbital centered on the α-nitrogen.

Frequency assignment and normal coordinate analysis for s-tetrazines

Abstract The low temperature infrared and Raman spectra of sym -tetrazine- d 0 , (C 2 H 2 N 4 ) and two of its deuterated forms, s-tetrazine- d 1 and s-tetrazine- d 2 , have been investigated to clarify the vibrational frequency assignment. Three possible assignments were developed and a normal coordinate analysis of the in-plane vibrations was used to select the best assignment.

Microwave Spectrum, Structure and Rotation-Vibration Interaction of Deutero-Fulminic Acid, DCNO

The microwave spectrum of the deuterated form of fulminic acid (DCNO) has been investigated in the frequency region from 9 to 42 GHz. For the ground vibrational state of DCNO the following rotational constants were obtained: B0(D12C14N16O) =10 292.50 MHz, B0(D13C14N18O) =10 011.66 MHz, B0(D12C14N18O) = 9 758.87 MHz. The corresponding moments of inertia yield a combined rs and r0 structure: rDC = 1.027 ±0.001 Å, rCN = 1·168 ±0.001 Å, rNO = 1.199 ± 0.001 Å. For the two degenerate bending modes ν4 and ν5 the l-type doublets of the transition J = 1 - 2 and the two corresponding series of l-type doubling transitions have been observed. The analysis of the two l-type doubling series revealed that P4 and P6 centrifugal distortion contributions are sufficient to account for the spectrum. The doubling constants given in MHz are q4 = 17.9103-(0.6467 · 10-4)J(J + 1) +(0.188 · 10-8) [J(J + 1)]2, q5 = 38.0907-(0.3061 · 10-3)J(J + 1) + (0.314 · 10-8)[J(J + 1) ]2. A third series of l-type doubling transitions arising from the II-level of the ν5=3 vibrational state has been found and analysed, yielding: q(0) 3×5 =29.2748 ± 1.8 · 10-4 MHz; EΦ-EII=Δ ≅ 41 cm-1.

Loroxanthin, a unique xanthophyll from scenedesmus obliquus and chlorella vulgaris

A unique xanthophyll, which had been detected before in certain green algae, has now been isolated from Scenedesmus obliquus and Chlorella vulgaris. This pigment, here called loroxanthin, has also been isolated in its deuterated form from fully deuterated Chlorella. It forms a triacetate, and with methanol plus HCl, it yields monomethyl and dimethyl ethers. It can be oxidized to an aldehyde, loroxanthal. It has been characterized as a hydroxy lutein with the additional hydroxy group on a chain methyl group, probably that on C 9. The previously reported absence of this pigment in C. pyrenoidosa has been confirmed. It was present in two marine Cladophora species and in Ulva rigida but absent in Spirogyra sp. and in two marine siphonalean green algae. It is probably not identical with certain similar pigments reported in other vegetable sources and variously described as trollein and trollein-like.

Electron Spin Resonance Study of γ-Irradiated Single Crystals of Semicarbazide Hydrochloride

Electron spin resonance studies of γ-irradiated single crystals of semicarbazide hydrochloride and the deuterated form, ND2CONHND3+·Cl−, revealed the presence of the stably trapped ·N(α)H(α) − N(β)H(β)3+ radical obtained by C–N bond rupture of the parent molecule. The principal g values were gaa = 2.0041 ± 0.0003, gbb = 2.0023, and gcc = 2.0044. The principal elements of the hyperfine couplings were found to be N(α) = 4.8 ± 4.0, 34.2 ± 1.0, and 11.8 ± 4.0 G; H(α) = − 10.5 ± 4.0, −27.6 ± 1.0, and −36.7 ± 4.0 G; N(β) = − 4 G; H(β) = 15 ± 0.5 G. The N(β) coupling was estimated from the angular dependence of the linewidths. The direction cosines of the N(α)and H(α) couplings were evaluated with reference to the orthorhombic crystallographic axes (a, b, c). The direction cosines of the N–H bond calculated from the ESR spectra were found to agree with those obtained by x-ray diffraction. The spin densities calculated for this radical indicate that the unpaired electron is highly localized on the α nitrogen, there being a spin density of 0.51 in the 2pπ orbital of the α nitrogen.

ORGANIC AND BIOLOGICAL SPECTROCHEMICAL STUDIES: XXII. THE INFRARED, ULTRAVIOLET, AND NUCLEAR MAGNETIC RESONANCE SPECTRA OF SOME SUBSTITUTED 2-INDANONES AND REFERENCE COMPOUNDS

Infrared, ultraviolet, and nuclear magnetic resonance spectra of the following compounds are reported: 2-indanone (I), trans- and cis-hexahydro-2-indanone (V and XI), 1-chloro-2-indanone-1,3,3-d3 (III), 1-bromo-2-indanone-1,3,3-d3 (IV), 1-chloro-trans-hexahydro-2-indanone (VII), 1-bromo-trans-hexahydro-2-indanone (VIII), some deuterated forms of these compounds, 2-chlorocyclohexanone-2,6,6-d3, and 2-bromocyclohexanone-2,6,6-d3.2-Indanone and trans-hexahydro-2-indanone each display two peaks in the carbonyl infrared region with intensity ratios of approximately 40:1. The origin of these doublets is discussed.Nuclear magnetic resonance spectra were determined to indicate the presence or absence of ring mobility, and spin–spin coupling data were used to support some of the conclusions deduced from the infrared data for some of the compounds.

Infrared Spectra of Metal Chelate Compounds. IX. A Normal Coordinate Analysis of Dithiocarbamato Complexes

The infrared spectra of dithiocarbamato and N-alkyldithiocarbamato complexes with various metals have been obtained in the range between 4000 and 280 cm—1. The spectra of their deuterated forms have also been obtained to confirm the band assignments. A normal-coordinate analysis has been carried out for the 1:1 (metal/ligand) model of the dithiocarbamato PtII complex. The results indicate that the Pt–S stretching bands are at 375 and 288 cm—1 and the corresponding Pt–S stretching force constant is 2.1×105 dyn/cm. The effects of changing the metal and of alkyl substitution on the electronic structure of these compounds have been inferred from the infrared spectra.

The effect of deuteration on the geometry of the α-helix

Experiments were carried out to determine the effect of complete deuteration on the screw parameters of the α-helix. Poly-γ-benzyl-L-glutamate and poly-β-benzyl-L-aspartate were drawn into fibers in both normal and deuterated forms, and an X-ray diffraction study was carried out on the change in the meridional 1·5 Å reflexion, which is a measure of the rise per residue along the helix. Deuteration increased this spacing by 0·007 Å and 0·008 Å respectively. Accompanying this was an increase in the helical pitch spacing of the 5·4 Å layer line which indicated that the deuterated α-helix was being extended, without a change in the rotation per residue. The hydrogen bond lengths of 2·83 Å are increased by 0·025 Å and 0·029 Å upon deuteration. This increase is in agreement with changes which have been observed in hydrogen bond length in other substances upon deuteration. The internal contacts of the α-helix are discussed, together with the effect of deuteration upon the overall stability of the structure. Infrared data are presented which confirm the helical form of the polymers in both normal and deuterated forms.

Dielectric Properties of a Sample of Deuterium Chloride containing an Impurity

FOLLOWING a fairly extensive study of the dielectric properties of solid hydrogen chloride in this Laboratory1, it was proposed to investigate the deuterated form. While hydrogen chloride was prepared by action of strong sulphuric acid on sodium chloride, deuterium chloride was obtained by dropping heavy water on thionyl chloride, the other product of the reaction being sulphur dioxide.