Charles J. Wurrey

Anaerobic degradation of trichloroethylene in soil.

face morphology, there was no evidence that the surface nodules were composed of any special, unique element. These particles from these particular collections seem to be quite similar to the micrometer size particles emitted in the ash (2). It is not clear, therefore, why the collected ash shows a bimodal distribution of micrometer size particles centered around 5 pm and submicrometer size particles centered around 0.5 pm. X-ray photoelectron spectroscopy (XPS) and depth profile XPS have been applied to these samples to determine surface composition. Results of these analyses will be presented in the near future.

Raman spectra of gases. XIII. Two‐quantum torsional transitions in some dihalo‐ and trihaloethanes

Methyl torsional overtones (Δν=2) have been observed for CH3CHCl2, CD3CDCl2, CH3CHBr2, CH3CCl3, CD3CCl3, CH3CBr3, CH3CCl2F, CH3CF2Br, and CH3CBr2Cl in the Raman effect. From the observed frequency shifts, barriers to internal rotation have been calculated to be 4.13, 4.13, 4.33, 5.43, 5.40, 5.78, 4.42, 5.06, and 5.70 kcal/mole, respectively. Some of these barriers have never been determined for the gas phase. Trends of barrier height as a function of halogen substitution are discussed for chlorine and bromine substitution.

Performance of a gas chromatographic-matrix isolation-Fourier transform infrared spectrometer

The unique matrix-isolated (MI) Fourier transform infrared spectra of diethyl ether, propanal, and trifluoromethane are compared with their vapor-phase spectra. The marked increase in resolution seen in the MI spectra is accompanied by substantial frequency shifts from the peaks in the vapor-phase spectra. The spectra were generated with a gas chromatographic/matrix isolation/Fourier transform infrared spectrometer, with the use of frozen Ar at 13 K as the isolating matrix. The spectra of the 22 isomers of tetrachlorodibenzo-p-dioxin show that each isomer can be distinguished and quantitated at the nanogram level. In addition, preliminary quantitative data were obtained for the pesticides Terbufos® and Fonofos®. Finally, a problem with a previously published spectrum of C-13 2,3,7,8-tetrachlorodibenzo-p-dioxin was uncovered, and it was shown that the spectrum was actually that of C-13 2,3,7-trichlorodibenzo-p-dioxin.

Conformational stability of ethylcyclopropane from Raman spectra, temperature dependent FT-IR spectra of xenon solutions and ab initio calculations

Abstract Infrared spectra (3500 to 400 cm −1 ) of xenon solutions of ethylcyclopropane, c -C 3 H 5 C 2 H 5 , at temperatures from −60 to −100°C have been recorded. In addition, Raman spectra of the liquid and polycrystalline phases have been obtained as well as infrared spectra of the gaseous phase. Spectroscopic evidence for the coexistence of the gauche and cis conformers of the title compound is found in the fluid phases. From the spectroscopic data, the enthalpy difference between the gauche and cis conformers has been estimated to be 385 cm −1 (1.10 kcal mol −1 ), with the gauche rotamer the more stable form. In the annealed solid phase, only the gauche conformer is found. Ab initio calculations have been carried with different basis sets up to MP 2 6-31 G , from which structural parameters, conformational stabilities, force constants, and vibrational frequencies have been determined. These calculations support the experimental conclusions and aid in the vibrational assignment of the normal modes. These results are compared to the corresponding quantities for some similar molecules.

Microwave spectra and barrier to internal rotation in cyclopropylmethylsilane.

Rotational spectra for 3 silicon isotopologues (28Si, 29Si, 30Si) of cyclopropylmethylsilane (c-C3H5SiH2CH3) have been observed in natural abundance using Fourier-transform microwave spectroscopy, and the dipole moment of the most abundant (28Si) isotopologue has been determined using the Stark effect. The observed rotational constants (A = 8800.5997(9) MHz; B = 2238.6011(3) MHz; C = 2001.0579(3) MHz) and dipole moment components (mu(a) = 0.195(2) D, mu(b) = 0.674(11) D, mu(c) = 0.362(19) D, mu(total) = 0.790(13) D) for the 28Si species are consistent with ab initio predictions (MP2/6-311+G(d)) for a gauche conformation about the Si-cyclopropyl bond. All of the observed transitions were split into doublets due to internal rotation of the methyl group, allowing a determination of the V3 barrier to internal rotation of 6.671(9) kJ mol(-1) for the most abundant isotopologue. This barrier will be compared to those for other Si-CH(3) containing compounds and will be related to a partial structure determination from the available microwave and ab initio data.

Microwave spectrum of (cyanomethyl) cyclopropane

Abstract The microwave spectrum of (cyanomethyl) cyclopropane has been studied. Only the gauche form of the molecule has been observed. This is consistent with the infrared results where the gauche form is found to be the dominant form (>85%). The rotational constants for the ground vibrational state are (in MHz) A = 10 800.703, B = 2014.942, C = 1835.685. From Stark effect measurements, the dipole moment is found to be 3.89 ± 0.08 D. Rotational transitions in several excited vibrational states also have been measured and assigned.

Gas Chromatographic/Matrix Isolation/Fourier Transform Infrared Spectra of the Laterally Chlorinated Dibenzo- p -Dioxins and Dibenzofurans

Reference-quality gas chromatographic/matrix isolation/Fourier transform infrared spectra have been recorded for the following fifteen compounds, which collectively are referred to as the “laterally” chlorinated dibenzo-p-dioxins and dibenzofurans: 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD); 1,2,3,7,8-pentachlorodibenzo-p-dioxin (1,2,3,7,8-PeCDD);l,2,3,4,7,8-hexachlorodibenzo-p-dioxin(1,2,3,4,7,8-HxCDD)>; 1,2,3,6,7,8,-hexachlorodibenzo-p-dioxin(1,2,3,6,7,8-HxCDD); 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin (1,2,3,7,8,9-HxCDD); 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (1,2,3,4,6,7,8-HpCDD); 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF); 1,2,3,7,8-pentachlorodibenzofuran (1,2,3,7,8-PeCDF); 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF); 1,2,3,4,7,8-hexachlorodibenzofuran(1,2,3,4,7,8-HxCDF); 1,2,3,6,7,8-hexachlorodibenzofuran (1,2,3,6,7,8-HxCDF); 1,2,3,7,8,9-hexachlorodibenzofuran (1,2,3,7,8,9-HxCDF); 2,3,4,6,7,8-hexachlorodibenzofuran (2,3,4,6,7,8-HxCDF); 1,2,3,4,6,7,8-heptachlorodibenzofnran (1,2,3,4,6,7,8-HpCDF); and 1,2,3,4,7,8,9-heptachlorodibenzofuran (1,2,3,4,7,8,9-HpCDF). These spectra are discussed qualitatively and, for the laterally chlorinated dioxins, are compared to previously recorded gas-phase GC/FT-IR spectra. Estimates of the instrumental detection limits for these compounds, using matrix isolation GC/FT-IR spectroscopy, were found to fall in the mid-to-high picogram and low nanogram ranges.

Vibrational spectra of cyclopropane derivatives. II. 1,1,2,2-Tetrabromocyclopropane and 1,1-dibromo-2,2-dichlorocyclopropane☆

Abstract The i.r. spectra of liquid 1,1,2,2-tetrabromocyclopropane and 1,1-dibromo-2,2-dichlorocyclopropane, both new compounds, have been measured from 4000-300 cm−1. Additionally, Raman spectra of the liquid and polycrystalline solid phases of both compounds have also been recorded. Based on the spectroscopic information, all 21 fundamental vibrations of the tetrabromo molecule have been confidently assigned while all but one of the normal modes of the dibromodichloro compound have been ascribed. For C3H2Br4, the spectra are consistent with the expected C2υ symmetry and excellent correlations between similar vibrational modes in 1,1,2,2-tetrabromo- and 1,1,2,2-tetrachlorocyclopropane are observed. For C3H2Br2Cl2, the Cs structure is confirmed from the spectroscopic data, and its vibrational frequencies are shown in many cases to be “averages” of the corresponding frequencies of the 1,1,2,2-tetrabromo-and 1,1,2,2-tetrachlorocyclopropane molecules. The effect of the atypical Cs symmetry of 1,1-dibromo-2,2-dichlorocyclopropane on the spectral data is discussed, cyclopropyl ring and CH2 group frequencies are discerned for both compounds, and frequency correlations for bromine vibrations in substituted cyclopropanes are deduced.

Spectra and structure of small ring compounds. XXXVI. 1-methylcyclopentene and 1,2-dimethylcyclopentene☆

Abstract The i.r. spectra of solid and gaseous 1-methylcyclopentene and 1,2-dimethylcyclopentene were recorded from 4000 to 33 cm −1 . The corresponding Raman spectra of the gases and liquids were measured. The fundamental vibrations of each compound have been assigned on the basis of group frequency correlations, band intensities, band contours and Raman depolarization values. The barrier hindering internal rotation of the methyl group has been calculated to be 1.93 kcal/mol for 1-methylcyclopentene. In 1,2-dimethylcyclopentene the methyl barrier is 1.77 kcal/mol for the B 2 vibrational mode.

Microwave spectrum, conformation, and low frequency vibrational spectrum of cyclopropylisothiocyanate

The microwave spectrum of cyclopropylisothiocyanate, c‐C3H5NCS, has been investigated in the region from 12.5 to 40.0 GHz. Two sets of a‐type R‐branch transitions were observed and assigned, on the basis of the rigid rotor model, to the trans and cis conformers. One excited vibrational state for each conformer was also identified and tentatively assigned as the asymmetric NCS torsion. The B and C rotational constants in the ground vibrational state for the trans and cis conformers of c‐C3H5NCS were found to be: B=1122.689±0.002, C=1095.619±0.002 MHz, and B=1346.859±0.003, C=1309.166±0.002 MHz, respectively. The values of the A rotational constants for both conformers were not well determined because the measured transitions are not very sensitive to these constants. The dipole moment components were determined for the trans conformer from the Stark effect to be ‖μa‖=3.11±0.02, ‖μc‖=0.62±0.01, and ‖μt‖=3.17±0.01 D and for the cis conformer to be ‖μa‖=3.34±0.01, ‖μb‖=0.27±0.07, and ‖μt‖=3.35±0.01 D. With re...