Examination of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part VII

1988 ◽  
Vol 42 (1) ◽  
pp. 108-113 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Solid State ◽  
Vapor Phase ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Infrared Spectrometry ◽  
Absorption Bands ◽  
The Matrix ◽  
Multiple Absorption ◽  
Carbonyl Absorption

A series of lactones and lactams have been examined by matrix isolation Fourier transform infrared spectrometry. The values for the carbonyl absorption bands fall between those reported for the same compounds in the vapor phase and solid state. Multiple absorption bands are found in the region of carbonyl absorption for compounds examined under the matrix isolation phase. Ring strain has a dramatic effect on simplifying the complexity of the spectra. Little or no aggregation effects are observed for either the lactones or lactams under accepted operating parameters. The effects of substituents on these systems are comparable to those found in the vapor-phase and solid-state data.

Examination of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part X

1988 ◽  
Vol 42 (4) ◽  
pp. 671-674 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Solid State ◽  
Vapor Phase ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
High Energy ◽  
Intramolecular Interactions ◽  
Absorption Bands ◽  
The Matrix ◽  
Energy Side

The characteristics of the OH stretching absorptions in a series of catechols, resorcinols, hydroquinones, and diols have been documented with the use of matrix isolation Fourier transform infrared spectroscopy. Steric and electronic effects were described and found to agree with published results on the vapor-phase studies on the same compounds. The positions of the OH absorptions were shown to fall within a window set on the high energy side by the vapor-phase results and on the lower energy side by solid-state/solution results. The very low full width at half-height values unique to the matrix experiment allowed for the observance of absorption bands not yet seen before in the vapor-phase or solid-state studies. These new bands confirm the presence of intramolecular interactions not previously documented. The data as a whole do indicate that extensive intermolecular interactions do occur at very low loadings on the cryogenic disk (10 ng) for compounds containing polar substituents.

Examination of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part VI

1988 ◽  
Vol 42 (1) ◽  
pp. 101-108 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Vapor Phase ◽  
Matrix Isolation ◽  
Spectral Structure ◽  
Absorption Bands ◽  
Rotational Isomers ◽  
Spectral Evidence ◽  
The Matrix ◽  
Ft Ir ◽  
Carbonyl Absorption

Matrix isolation Fourier transform spectral evidence is presented that documents the isolation of rotational isomers in an argon matrix. The spectral evidence is based on the presence of split carbonyl absorption bands in the spectra of selected derivatives of methyl acetate which do not vary in intensity with changes in the matrix-to-eluate ratios. The results compare very favorably with FT-IR data on the identical compounds obtained in the vapor phase. The low temperature of the matrix isolation experiment (10 K) allows for the observance of rotational isomers not seen at the high temperatures of the vapor-phase experiment (500 K). The presence of multiple carbonyl absorption bands dictates that careful attention must be paid to spectral/structure correlations employing MI/FT-IR data.

Examination of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part III

1987 ◽  
Vol 41 (7) ◽  
pp. 1163-1169 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Solid State ◽  
Vapor Phase ◽  
Infrared Spectra ◽  
Steric Hindrance ◽  
Fourier Transform Infrared ◽  
Fourier Transform Infrared Spectra ◽  
The Matrix ◽  
Ft Ir ◽  
Carbonyl Absorption

Matrix-isolated (MI) Fourier transform infrared spectra (FT-IR) have been collected on a series of esters and ketones. The values for the carbonyl absorption are intermediate between the values for vapor-phase (VP) and solid-state (SS) phases. The spectra reveal a splitting or broadening of the carbonyl absorption in the majority of cases for both compound types. The splitting, on the order of 5 to 10 cm−1, does not appear to be a function of concentration at ≤20 ng on the cryogenic disk. The splitting is also not unequivocally due to steric hindrance about the carbonyl group. Compounds with liner as well as branched substituents display spectra having split carbonyl absorptions. Isolation of molecules within multiple types of matrix sites is advanced as the predominant cause of the splitting phenomenon. Implications and consequences of the observed splitting are discussed.

Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part XVII

1989 ◽  
Vol 43 (8) ◽  
pp. 1424-1427 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Quantitative Analysis ◽  
Matrix Isolation ◽  
Complex Mixture ◽  
Fourier Transform Infrared ◽  
Mass Range ◽  
Infrared Spectrometry ◽  
Flame Ionization ◽  
The Matrix ◽  
Ft Ir

Qualitative and quantitative analysis of compounds in a complex mixture by gas chromatography/matrix isolation/Fourier transform infrared spectrometry (GC/MI/FT-IR) is described. The carbon-deuterium stretching mode was characterized and used for analysis since it has a unique position in the infrared spectrum. Compounds of varying functionalities were examined over a concentration range from 6 to 50 ng. Linear responses over this mass range were obtained. Flame ionization detection was used for collaborative detection in establishing the linearity of the responses. These results represent the first use of GC/MI/FT-IR for quantitative analysis of compounds in a complex mixture using deuterium-labeled analogues.

Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part XVI

1989 ◽  
Vol 43 (6) ◽  
pp. 1008-1016 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Ir Spectra ◽  
Vapor Phase ◽  
Infrared Spectra ◽  
Condensed Phase ◽  
Matrix Isolation ◽  
Absorption Bands ◽  
Argon Matrix ◽  
The Matrix ◽  
The Impact

Information concerning the matrix isolation Fourier transform infrared spectra of a series of alkanes, esters, lactones, lactams, phenols, alcohols, amides, alkenes, and ketones is presented. A comparison between the characteristics of the spectra in two matrices (argon and xenon) as well as in the absence of any matrix (bare gold disk) is drawn. The impact of these matrices on the characteristics of the IR spectra is compared with the impact observed when spectra are gathered in the vapor phase as well as the condensed phase/solid state. For the majority of compounds studied, the major absorption bands of each class of compound fall between higher values for the vapor phase and lower values for the condensed phase when either argon or xenon is used as the matrix gas. The few exceptions are discussed. The absorption bands found in the xenon matrix are usually at a lower energy than are comparable bands in the argon matrix. In most all cases, the values of absorptions for compounds on the bare disk were lower than the comparable values found in the argon matrix. These results represent the first extensive study at 10 K of the effect of different matrix gas hosts and document the proposal that preconceptions of noble gases as inert hosts for the examination of FT-IR spectra at low temperature are not valid.

Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part IX

1988 ◽  
Vol 42 (4) ◽  
pp. 666-670 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Organic Compounds ◽  
Infrared Spectra ◽  
Nearest Neighbor ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Absorption Bands ◽  
The Matrix ◽  
Chain Lengths

A series of β-diketones and alkenes have been examined by matrix isolation Fourier transform infrared spectroscopy. The matrix experiment readily detects the presence of extensive keto-enol tautomerization in selected β-diketones. Certain absorption bands in the IR could be used to estimate the extent of the tautomerization. The data gathered on the alkenes found their absorption bands to occur in the same regions (±5 cm−1) as those found for VP and SS phases. Minimal nearest-neighbor (aggregation) interactions were found. These results are in contrast to those found for aldehydes, ketones, and acids of similar chain lengths.

Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part VIII

1988 ◽  
Vol 42 (2) ◽  
pp. 304-309 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Organic Compounds ◽  
Vapor Phase ◽  
Infrared Spectra ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Argon Matrix ◽  
Fourier Transform Infrared Spectra ◽  
The Matrix ◽  
Ft Ir

Matrix isolation Fourier transform infrared (MI/FT-IR) data has been presented that documents the presence of discrete conformers in an argon matrix for a series of ketones. The distribution of conformers in the matrix was related to the structure of the molecule, in that rigid structures (i.e., small rings, bicyclic systems, and unsaturated systems) displayed simple carbonyl absorption patterns relative to those of their less rigid counterparts. Also, conformer isolation was seen for halosubstituted ketones. These results are in agreement with previous findings concerning the vapor-phase (VP) spectra of these molecules.

scholarly journals Analysis of IHchothecene Mycotoxins in Contaminated Grains by Gas Chromatography/Matrix Isolation/Fourier Transform Infrared Spectroscopy and Gas Chromatography/Mass Spectrometry

1996 ◽  
Vol 79 (5) ◽  
pp. 1116-1123 ◽  
Author(s):  
Magdi M Mossoba ◽  
Sarah Adams ◽  
John A G Roach ◽  
Mary W Trucksess
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Fourier Transform ◽  
Sweet Corn ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Epoxide Ring ◽  
Absorption Bands ◽  
Spectral Bands ◽  
Infrared Spectral

Abstract Gas chromatography/matrix isolation/Fourier transform infrared (GC/MI/FTIR) spectroscopy and GC/mass spectrometry (MS) were used to confirm the identities of trimethylsilyl (TMS) derivatives of trichothecene mycotoxins in naturally contaminated grains. Infrared spectral bands observed in the fingerprint region were unique for 10 trichothecene standards. Characteristic absorption bands were observed for the ester (near 1750 cm-1) and ketone (near 1700 cm-1) carbonyl stretching vibrations, the acetate CH3 symmetric bend (1370 cm-1), the epoxide ring (1262 cm-1), the trimethylsilyl CH3 in-plane deformation (1253 cm-1), the ester (O)C-O asymmetric stretching vibration (near 1244 cm-1), and several other bands including intense features due to the TMS function. Infrared bands observed under cryogenic matrix isolation conditions were compared with those found at room temperature in a potassium bromide matrix for 5 of these standards. Identities of deoxynivalenol (DON) from barley and mixed feed, nivalenol from wheat and barley, and DON and fusarenon-x from sweet corn were confirmed by comparison of their infrared spectral bands with those of standards. The identity of DON in the same test samples of sweet corn was confirmed further by GC/MS. GC/MS was also used to quantitate the levels of DON (67-455 ppm) in sweet corn test samples.

Matrix Isolation/Fourier Transform Infrared Spectrometry of Laser-Desorbed Species

1995 ◽  
Vol 49 (7) ◽  
pp. 955-963 ◽  
Author(s):  
B. L. Carr ◽  
R. S. Brown
Keyword(s):  
Fourier Transform ◽  
Carbon Dioxide Laser ◽  
Matrix Isolation ◽  
Sinapinic Acid ◽  
Laser Desorption ◽  
Fourier Transform Infrared ◽  
Maldi Mass Spectrometry ◽  
Infrared Spectrometry ◽  
Coumaric Acid ◽  
Experimental Conditions

Initial results are presented for a novel experimental arrangement which allows the successful study of laser-desorbed neutral species under matrix isolation conditions. In the current work, a pulsed carbon dioxide laser (10.6 μm) is employed for laser desorption. With the combination of a previously described cryogenic trapping technique with coaxial matrix isolation gas (xenon or argon) introduction, laser-desorbed neutrals have been matrix isolated and their Fourier transform infrared spectra recorded. Two different cinnamic acid derivatives ( p-coumaric acid and sinapinic acid) typically employed for matrix-assisted laser ionization (MALDI) mass spectrometry were utilized to demonstrate this new technique. Experimental conditions were determined for optimal matrix isolation of the laser-desorbed species. Two different desorption geometries were examined with respect to their effectiveness for matrix isolation of desorbed neutrals. A covalent dimer of p-coumaric acid produced in an external UV photoreactor and thought to be a possible photoreaction product in UV MALDI was studied by this technique. Thermal degradation of this dimer is shown to occur above threshold irradiance for laser desorption.

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