scholarly journals Carbonyl Absorption Bands in the Infrared Spectra of Some Cyclic Imides with a Five-membered Ring

1964 ◽  
Vol 37 (12) ◽  
pp. 1844-1848 ◽  
Author(s):  
Taku Matsuo
Keyword(s):  
Infrared Spectra ◽  
Membered Ring ◽  
Absorption Bands ◽  
Cyclic Imides ◽  
Carbonyl Absorption

ORGANOGERMANIUM COMPOUNDS: PART II. INFRARED SPECTRA OF SOME ACOXYGERMANES AND THE RELATIVE INDUCTIVE EFFECTS OF TRIMETHYLSILYL AND TRIMETHYLGERMYL GROUPS

1963 ◽  
Vol 41 (5) ◽  
pp. 1244-1249 ◽  
Author(s):  
T. N. Srivastava ◽  
M. Onyszchuk
Keyword(s):  
Gas Phase ◽  
Infrared Spectra ◽  
Absorption Bands ◽  
Organogermanium Compounds ◽  
Inductive Effects ◽  
Electron Release ◽  
Carbonyl Absorption ◽  
Lower Frequencies

The infrared spectra of GeH3OCOCH3 and (CH3)3GeOCOCH3 have been measured in the gas phase over the range 650–3900 cm−1. Assignments for the principal bands have been made and their values compared with those of analogous alkyl, methylsilyl, methyltin, and methyllead acetates. Carbonyl absorption bands shift to lower frequencies and carbon–oxygen (skeletal) absorptions to higher frequencies as M changes from C to Si to Ge in the series of acetates represented by (CH3)3MOCOCH3. These results suggest that the Ge—O bond is more polar than the Si—O bond and that the order of electron release in acetate derivatives is (CH3)3Ge > (CH3)3Si > (CH3)3C, which is consistent with the electronegativity order: C > Si > Ge.

Pyrrole Studies. I. The Infrared Spectra of 2-Monosubstituted Pyrroles

1963 ◽  
Vol 16 (1) ◽  
pp. 93 ◽  
Author(s):  
RA Jones
Keyword(s):  
Infrared Spectra ◽  
Infrared Absorption ◽  
Absorption Bands ◽  
Infrared Absorption Bands

The positions and intensities of the characteristic infrared absorption bands of the nucleus are recorded and discussed for thirty-five 2-monosubstituted pyrroles.

scholarly journals THE USE OF INFRARED SPECTROPHOTOMETRY FOR THE ESTIMATION OF SMALL QUANTITIES OF SOME HALOGENATED HYDROCARBONS

1953 ◽  
Vol 31 (4) ◽  
pp. 328-337 ◽  
Author(s):  
L. Breitman ◽  
E. W. R. Steacie
Keyword(s):  
Quantitative Analysis ◽  
Carbon Tetrachloride ◽  
Gas Phase ◽  
Infrared Spectra ◽  
Methyl Chloride ◽  
Ternary Mixtures ◽  
Halogenated Hydrocarbons ◽  
Infrared Spectrophotometry ◽  
Absorption Bands ◽  
Binary And Ternary Mixtures

The infrared spectra of chloral, carbon tetrachloride, and chloroform have been determined between 1500 and 650 cm.−1 over a range of pressures in the gas phase. Absorption bands suitable for the quantitative analysis of binary and ternary mixtures of the components have been selected and their peak intensities shown to obey Beer's Law over the range of pressures studied. Ternary mixtures have been analyzed from the spectra with an accuracy of about 20%.The spectra of dichloromethane and methyl chloride have also been measured under comparable conditions.

Gaseous infrared spectra of the simplest geminal diol CH2(OH)2 and the isotopic analogues in the hydration of formaldehyde

2021 ◽  
Author(s):  
Hung-Yang Jain ◽  
Chih-Tsun Yang ◽  
Li-Kang Chu
Keyword(s):  
Infrared Spectrum ◽  
Infrared Spectra ◽  
Absorption Bands ◽  
Geminal Diol

The infrared spectrum of the simplest geminal diol, methanediol or methylene glycol (CH2(OH)2), was successfully probed in the gaseous hydration of formaldehyde. The observed absorption bands coincided with the anharmonic...

scholarly journals Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: sparse methods for statistical selection of relevant absorption bands

2016 ◽  
Vol 9 (7) ◽  
pp. 3429-3454 ◽  
Author(s):  
Satoshi Takahama ◽  
Giulia Ruggeri ◽  
Ann M. Dillner
Keyword(s):  
Infrared Spectra ◽  
Atmospheric Aerosols ◽  
Quantitative Prediction ◽  
Calibration Model ◽  
Vibrational Modes ◽  
Aerosol Composition ◽  
Absorption Bands ◽  
Calibration Models ◽  
Ft Ir ◽  
Selection Of

Abstract. Various vibrational modes present in molecular mixtures of laboratory and atmospheric aerosols give rise to complex Fourier transform infrared (FT-IR) absorption spectra. Such spectra can be chemically informative, but they often require sophisticated algorithms for quantitative characterization of aerosol composition. Naïve statistical calibration models developed for quantification employ the full suite of wavenumbers available from a set of spectra, leading to loss of mechanistic interpretation between chemical composition and the resulting changes in absorption patterns that underpin their predictive capability. Using sparse representations of the same set of spectra, alternative calibration models can be built in which only a select group of absorption bands are used to make quantitative prediction of various aerosol properties. Such models are desirable as they allow us to relate predicted properties to their underlying molecular structure. In this work, we present an evaluation of four algorithms for achieving sparsity in FT-IR spectroscopy calibration models. Sparse calibration models exclude unnecessary wavenumbers from infrared spectra during the model building process, permitting identification and evaluation of the most relevant vibrational modes of molecules in complex aerosol mixtures required to make quantitative predictions of various measures of aerosol composition. We study two types of models: one which predicts alcohol COH, carboxylic COH, alkane CH, and carbonyl CO functional group (FG) abundances in ambient samples based on laboratory calibration standards and another which predicts thermal optical reflectance (TOR) organic carbon (OC) and elemental carbon (EC) mass in new ambient samples by direct calibration of infrared spectra to a set of ambient samples reserved for calibration. We describe the development and selection of each calibration model and evaluate the effect of sparsity on prediction performance. Finally, we ascribe interpretation to absorption bands used in quantitative prediction of FGs and TOR OC and EC concentrations.

Investigation of Spectral Sensitization III. A Study of the Visible and Infrared Spectra of Some Very Pure Bis-Thiazolinyl and Bis-Thiazolyl Cyanine Iodides

1966 ◽  
Vol 20 (3) ◽  
pp. 150-158 ◽  
Author(s):  
A. Leifer ◽  
M. Boedner ◽  
P. Dougherty ◽  
A. Fusco ◽  
M. Koral ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Low Frequency ◽  
Red Shift ◽  
Absorption Bands ◽  
Spin Resonance ◽  
Visible Spectra ◽  
Bond System ◽  
Phenyl Rings ◽  
In Series ◽  
Systematic Group

A detailed study of the visible spectra in solution and the infrared spectra of the dyes in the solid state have been made for the following vinylogous series of cyanine dyes: [2-bis(3-ethylthiazolinyl)] cyanine iodides, I; [2-bis(3-ethyl-4-methylthiazolyl)] cyanine iodides, II; and [2-bis(3-ethyl-4,5-diphenylthiozolyl] cyanine iodides, III. Each dye, to be acceptable for study, had to be chromatographically pure, give a correct microchemical elemental analysis, and be free of electron-spin resonance (free radical) signals. These vinylogous series of dyes form a systematic group. That is, in series I there is only a resonant conjugated chain of alternate single and double bonds present between the two nitrogen atoms; in series II there are additional olefinic unsaturated bonds which are in conjugation with the resonant conjugated chain; and in series III there are additional phenyl rings in conjugation with the entire pi bond system present in II. The characteristic red shift of the principal absorption maxima was observed for these dyes in the visible as the number of methine linkages increased. Furthermore, a small relative red shift of the absorption maxima has been observed for this group of dyes and has been interpreted on the basis of the type of unsaturation present in conjugation with the resonant conjugated chain. Assignments of vibrational modes to separate absorption regions have been made for these vinylogous series of dyes. A correlation of the dye structure with the absorption bands has been made. Each vinylog gave rise to a characteristic pattern of resonant conjugated stretching modes in the region 1600 to 1400 cm−1. These modes exhibited a low frequency shift as the resonant conjugated chain-length increased. For a constant number of polymethine linkages these modes are a function of the type of unsaturation present which is in conjugation with the resonant conjugated chain.

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.

The infrared spectra of theobromine salts

1967 ◽  
Vol 45 (23) ◽  
pp. 2899-2902 ◽  
Author(s):  
Denys Cook ◽  
Zephyr R. Regnier
Keyword(s):  
Hydrogen Bond ◽  
Nitrogen Atom ◽  
Infrared Spectra ◽  
Imidazole Ring ◽  
Free Base ◽  
Absorption Bands ◽  
Out Of Plane ◽  
Stretching Vibrations ◽  
Deformation Modes ◽  
Infrared Absorption Bands

From the infrared spectra of theobromine salts it is concluded that the salts are probably arranged in hydrogen-bonded centrosymmetric pairs involving [Formula: see text] interactions. [Formula: see text] anion− hydrogen bonds are formed by protonation of the free nitrogen atom (N9) in the imidazole ring. Infrared absorption bands arising from the former hydrogen bond constantly appear near 3 000 cm−1, whereas those from the latter shift from 2 580 to 3 300 cm−1, depending on the anion. In-plane NH and N+H deformation modes give bands near 1 485 and 1 160 cm−1, respectively. Out-of-plane NH modes have been located, but precise assignments are not possible.The assignments for some other bands which show deuteration shifts are detailed, and the carbonyl stretching vibrations which increase in frequency on protonation of the free base are identified.

Studies on metal hydroxy compounds. II. Infrared spectra of zinc derivatives ϵ-Zn(OH)2, β-ZnOHCl, ZnOHF, Zn5(OH)8Cl2, and Zn5(OH)8Cl2·H2O

1967 ◽  
Vol 45 (6) ◽  
pp. 585-588 ◽  
Author(s):  
O. K. Srivastava ◽  
E. A. Secco
Keyword(s):  
Infrared Spectra ◽  
Group Factor ◽  
Absorption Bands ◽  
Site Group ◽  
Planar Molecule ◽  
Stretching Vibration ◽  
Hydroxy Compounds ◽  
A Site ◽  
First Time ◽  
Unambiguous Assignment

Infrared spectra of ϵ-Zn(OH)2, β-ZnOHCl, ZnOHF, Zn5(OH)8Cl2, and Zn5(OH)8Cl2·H2O and their deuterated analogues in the range 2.5–16 μ are reported for the first time. The effects of substituting a halogen for an OH group in Zn(OH)2 are (i) sharper OH stretching absorption bands, (ii) splitting of bands involving OH to give distinct doublets in ZnOHF and Zn5(OH)8Cl2, indicating strong intermolecular coupling, and (iii) shift of the OH stretching vibration to a higher frequency. Strong absorption bands are observed in the region of 695–780 cm−1 for all compounds and also near 1 020 ± 30 cm−1 in all cases except ZnOHCl. All the observed bands are displaced to lower frequencies by the deuterated analogues, with vH/vD ratios in the range 1.30–1.36. A cursory interpretation of the spectra of ZnOHCl and ZnOHF is given in terms of a planar molecule of Cs symmetry, but the unambiguous assignment of the bands must await a site group or group factor analysis.

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