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 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.

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.

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

1989 ◽  
Vol 43 (6) ◽  
pp. 1004-1008 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Infrared Spectra ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Argon Matrix ◽  
Fourier Transform Infrared Spectra ◽  
The Matrix ◽  
Ft Ir ◽  
Oil Components ◽  
Search Routine

Matrix isolation Fourier transform infrared spectra (MI/FT-IR) of a series of essential oil components have been described. Clear, well-defined differences were detected in the MI/FT-IR spectra of compounds having minor differences in their structure. A library search routine was found to correctly identify components of interest when visual differences were not clearly evident. The presence of discrete conformers in the argon matrix resulted in the presence of split absorptions in the carbonyl band for selected compounds.

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.

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 XII

1989 ◽  
Vol 43 (2) ◽  
pp. 298-304 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon ◽  
Brian M. Lawrence
Keyword(s):  
Fourier Transform ◽  
Ir Spectra ◽  
Infrared Spectra ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Fourier Transform Infrared Spectra ◽  
The Matrix ◽  
Ft Ir ◽  
Nanogram Level ◽  
C Nmr

Matrix isolation Fourier transform infrared spectra (MI/FT-IR), mass spectra (MS), carbon-13 Nuclear Magnetic Resonance (13C-NMR) spectra, condensed-phase infrared spectra, and vapor-phase infrared (IR) spectra are presented for a series of terpene compounds. Subtle differences in positional and configurational isomers commonly found with terpenes could be easily detected by the MI/FT-IR spectra. The results are comparable in some aspects to those obtainable from 13C-NMR and thin-film IR; however, most importantly, they are acquired at the low nanogram level for MI/FT-IR, as compared to the milligram level for the other techniques. These results represent an advance in the technology available for the analysis of complex mixtures such as essential oils containing terpene-like molecules.

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.

Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds. Part XIV: Evaluation of Library Search Routines for Identification of Essential Oil Components

1989 ◽  
Vol 43 (6) ◽  
pp. 998-1003 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Infrared Spectra ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Absolute Difference ◽  
Citronella Oil ◽  
Fourier Transform Infrared Spectra ◽  
The Matrix ◽  
Ft Ir ◽  
Lemon Oil

A set of five search routines—absolute difference, absolute derivative, square difference, square derivative, and Euclidean difference—have been applied to the analysis of the matrix isolation/Fourier transform-infrared spectra (MI/FT-IR) of the components of four essential oils: coriander oil, lemon oil, geranium oil, and citronella oil. The routines were tested under a variety of parameters on a diverse set of compounds and IR spectra. Areas of acceptable performance by the routines as well as areas of marginal performance are discussed. Under the conditions of this study, the absolute derivative routine is judged to be the most acceptable of the five.

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.

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