Examinations of the Matrix Isolation Infrared Spectra of Organic Compounds: PART XIII

1989 ◽  
Vol 43 (2) ◽  
pp. 305-310 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Ir Spectra ◽  
Organic Compounds ◽  
Matrix Isolation ◽  
Intramolecular Hydrogen Bonding ◽  
Double Bond Position ◽  
Absorption Bands ◽  
The Matrix ◽  
Carbon Substitution ◽  
Ft Ir ◽  
Intramolecular Hydrogen

Matrix isolation Fourier transform infrared (MI/FT-IR) spectra have been collected on a series of internal alkenes, a series of hydroxy-substituted ketones, and a series of hydroxy-substituted esters. Assignments of double bond position and geometry are possible in the alkenes, due to the resolution of absorption bands of very similar energies. The location of the absorption bands for the alkenes was found to be very similar to the values found for the vapor-phase and condensed-phase spectra. Multiple carbonyl absorptions have been found in the MI/FT-IR spectra of the hydroxy ketones and hydroxy esters. Trends in the multiplicity of the carbonyl absorption patterns for these compounds as a function of ring size and hydroxyl carbon substitution have been used to document the presence of extensive intramolecular hydrogen bonding. The argon matrix as a phase for the study of stable organic compounds has, again, with this information, been shown to be unique.

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

1988 ◽  
Vol 42 (6) ◽  
pp. 1049-1056 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Hydrogen Bonding ◽  
Fourier Transform ◽  
Organic Compounds ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Intramolecular Hydrogen Bonding ◽  
Carbonyl Groups ◽  
Band Broadening ◽  
The Matrix ◽  
Intramolecular Hydrogen

Matrix isolation Fourier transform infrared information has been presented on a series of aliphatic amines, anilines, and amides. The absorptions associated with NH stretches are found at essentially the same energies in both the vapor phase (VP) and matrix isolation (MI) phase. Both the VP and MI values are found at higher energy than the solid state (SS) phase. The similarity of the values for the MI and VP phases is a departure from results found previously for other types of organic compounds. The carbonyl absorptions for the amides (MI) were found to be intermediate between the VP (high) and SS (low) values. This is consistent with established trends for other carbonyl containing compounds. The absorptions for carbonyl groups for the majority of the compounds appear as split absorptions on the order of 20 cm−1 peak to peak. These split absorptions were ascribed to intramolecular hydrogen bonding and rotational conformer isolations. Minor aggregation effects were found to occur as band broadening effects when the ratio of matrix gas (argon) to analyte dropped below 1000:1.

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 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.

Matrix-Isolation Infrared Spectroscopy of Organic Phosphates

1994 ◽  
Vol 48 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Lisa George ◽  
K. Sankaran ◽  
K. S. Viswanathan ◽  
C. K. Mathews
Keyword(s):  
Alkyl Chain ◽  
Matrix Isolation ◽  
Intramolecular Hydrogen Bonding ◽  
Alkyl Chain Length ◽  
Triethyl Phosphate ◽  
Trimethyl Phosphate ◽  
The Matrix ◽  
Intramolecular Hydrogen ◽  
First Time ◽  
Peak Widths

Matrix-isolation infrared spectra of trimethyl phosphate (TMP), triethyl phosphate (TEP), and tri- n-butyl phosphate (TBP), in argon and nitrogen matrices, are reported for the first time. The peak widths of the sharpest features in our matrix-isolated spectra are typically 2 cm−1, compared with peak widths of 40 cm−1 seen in liquids for these compounds. Comparison with the vapor-phase spectrum of TMP reported earlier indicates that TMP is trapped in two different conformations in these matrices. Similar spectra were also obtained for TEP. Our matrix-isolated spectra indicate that the intramolecular hydrogen bonding (which is believed to be responsible for the lowering of the P=O frequency in the C3, conformer relative to the C3 conformer in these compounds) is stronger in TEP than in TMP. In the case of TBP, the peak widths were larger (8–10 cm−1) than those obtained for TMP and TEP. This observation is probably due to a distribution of conformers that may be trapped in the matrix, as a result of the increased alkyl chain length in TBP.

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.

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.

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