Infrared spectra of compounds with the methoxymethyl protecting group

1986 ◽  
Vol 51 (1) ◽  
pp. 90-100 ◽  
Author(s):  
Soňa Vašíčková ◽  
Vladimír Pouzar ◽  
Ivan Černý ◽  
Pavel Drašar ◽  
Miroslav Havel
Keyword(s):  
Infrared Spectra ◽  
Strong Absorption ◽  
Protecting Group ◽  
Absorption Bands ◽  
Stretching Vibrations

Infrared spectra of a series of compounds containing the CH3OCH2O- (MOM-O-) group have been studied. All the spectra exhibit three characteristic strong absorption bands due to coupled stretching vibrations of C-O-C-O-C grouping in the region 1 200 - 1 000 cm-1.

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.

Angular Dependence of Diffuse Reflectance Infrared Spectra. Part III: Linearity of Kubelka-Munk Plots

1988 ◽  
Vol 42 (2) ◽  
pp. 242-247 ◽  
Author(s):  
Paul J. Brimmer ◽  
Peter R. Griffiths
Keyword(s):  
Angular Dependence ◽  
Infrared Spectra ◽  
Diffuse Reflectance ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Linear Region ◽  
Line Configuration ◽  
Munk Function ◽  
Before And After ◽  
Diffuse Reflectance Infrared

The linearity of plots of the Kubelka-Munk function against concentration is investigated for weak and strong absorption bands in the spectrum of a typical organic analyte, caffeine. The linear region is extended when measurements are made with an off-axis optical geometry, in comparison to an in-line configuration. For the latter configuration, the linearity is improved when crossed polarizers are placed before and after the sample.

scholarly journals Infrared, 1H and 13C NMR Spectra of N,N-Dichloroarylsulphonamides, 4-X-C6H4SO2NCl2 (X = H, CH3, C2H5, F, Cl or Br) and i-X, j-YC6H3SO2NCl2 (i-X, j-Y = 2,3-(CH3)2, 2,4-(CH3)2, 2,5-(CH3)2, 2-CH3, 4-Cl, 2-CH3, 5-Cl, 3-CH3, 4-Cl, 2,4-Cl2 or 3,4-Cl2)

2003 ◽  
Vol 58 (9-10) ◽  
pp. 563-568
Author(s):  
B. Thimme Gowda ◽  
K. Jyothi ◽  
N. Damodara
Keyword(s):  
Infrared Spectra ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Empirical Correlations ◽  
Absorption Bands ◽  
1H And 13C Nmr ◽  
Modes Of Vibration ◽  
Stretching Vibrations ◽  
Electron Donating Groups ◽  
Infrared Absorption Bands

Several mono- and di-substituted N,N-dichloroarylsulphonamides of the configuration, 4-XC6H4SO2NCl2 (where X = H, CH3, C2H5, F, Cl or Br) and i-X, j-YC6H3SO2NCl2 (where i- X, j-Y = 2,3-(CH3)2, 2,4-(CH3)2, 2,5-(CH3)2, 2-CH3,4-Cl, 2-CH3,5-Cl, 3-CH3,4-Cl, 2,4-Cl2 or 3,4-Cl2), respectively, were prepared, characterised and their infrared spectra in the solid state and NMR spectra in solution state were measured and correlated. Comparison of the infrared spectra of the N,N-dichloroarylsulphonamides with the corresponding arylsulphonamides and Nchloroarylsulphonamides revealed that the infrared absorption bands in the ranges, 790 - 735 cm−1 and 595 - 546 cm−1 are due to N-Cl asymmetric and symmetric stretching vibrations, respectively, and that the effect of ring substitution on the N-Cl frequencies is not consistent. The frequencies in the ranges 1384 - 1333 cm−1 and 1181 - 1143 cm−1 are, respectively, assigned to S=O asymmetric and symmetric modes of vibration. The effect of substitution in the phenyl ring in terms of electron withdrawing and electron donating groups is non-systematic. Since the chemical shift depends on the electron density around the nucleus, empirical correlations relating the chemical shifts to the structures have been considered. The chemical shifts of aromatic protons and carbons in all the N,Ndichloroarylsulphonamides have been calculated by adding substituent contributions to the shift of benzene. Considering the approximation made, the agreement between the calculated and experimental chemical shifts is good.

Preparation and infrared spectra of some ammine complexes of ruthenium(II) and ruthenium(III)

1967 ◽  
Vol 45 (12) ◽  
pp. 1337-1341 ◽  
Author(s):  
A. D. Allen ◽  
C. V. Senoff
Keyword(s):  
Solid State ◽  
Infrared Spectra ◽  
Absorption Bands ◽  
Ammine Complexes ◽  
Stretching Vibrations

The infrared spectra of the complexes [Ru(NH3)6]X2 and [Ru(NH3)6]X3, where X = Cl−, Br−, I−, BF4− and [Ru(NH3)5X]X2, where X = Cl−, Br− and I−, have been measured in the solid state between 4 000 – 250 cm−1. Assignments have been made for the observed absorption bands. The metal–nitrogen stretching vibrations were observed between 485–424 cm−1 for the ruthenium(III) complexes but were not observed for the ruthenium(II) complexes in this region.

INFRARED SPECTRA AND THE STRUCTURES OF XANTHATES AND DIXANTHOGENS

1961 ◽  
Vol 39 (8) ◽  
pp. 1633-1637 ◽  
Author(s):  
M. L. Shankaranarayana ◽  
C. C. Patel
Keyword(s):  
Metal Complexes ◽  
Infrared Spectra ◽  
Strong Absorption ◽  
Canonical Structure ◽  
Absorption Bands ◽  
Ionic Compounds ◽  
Structure Formula ◽  
Xanthic Acid

The infrared spectra of representative dialkyl dixanthogens and a few xanthates have been examined. All these compounds have two strong absorption bands in the regions 1140–1265 and 1010–1080 cm−1. On the basis of the shift of the bands with the changes in the substituents in the xanthic acid, the former band is assigned to the C=S group, while the latter to the CO group. Except in the ionic compounds, the canonical structure [Formula: see text] contributes very little to the structures of dixanthogens and covalent metal complexes.

Infrared Spectra of 2,9-Dimethyl-1,10-phenanthroline, Its Hydrates and Acid Perchlorate

1962 ◽  
Vol 15 (3) ◽  
pp. 425 ◽  
Author(s):  
ECM Grigg ◽  
JR Hall ◽  
RA Plowman
Keyword(s):  
Infrared Spectra ◽  
Plane Motion ◽  
Ring System ◽  
Hydrogen Atoms ◽  
Absorption Bands ◽  
Out Of Plane ◽  
Intense Absorption ◽  
Infrared Absorption Spectra ◽  
Stretching Vibrations ◽  
Phase Out

Infrared absorption spectra of 2,9-dimethyl-1,10-phenanthroline (dmp), dmp 0.5H2O, dmp 2H2O, and dmp HClO4 have been obtained over the range 4000-650 cm-1. Bands between 1610 and 1545 cm-1 are attributed to stretching vibrations within the phenanthroline ring system. The in-phase out-of-plane motion of the ring hydrogen atoms is associated with intense absorption at 845 cm-1. A strong band is observed at 728 cm-1 which cannot be accounted for in terms of an out-of-plane CH deformation. The perchlorate is characterized by shifts of the strongest absorption bands observed in the spectra of dmp and the hydrates.

Studies on metal hydroxy compounds. IV. Infrared spectra of cadmium derivatives Cd(OH)2, CdOHCl, and CdOHF

1967 ◽  
Vol 45 (24) ◽  
pp. 3199-3201 ◽  
Author(s):  
O. K. Srivastava ◽  
E. A. Secco
Keyword(s):  
Infrared Spectra ◽  
Strong Absorption ◽  
Lattice Vibrations ◽  
Absorption Bands ◽  
Simple Molecule ◽  
Stretching Vibration ◽  
Hydroxy Compounds ◽  
First Time ◽  
Lower Frequencies

Infrared spectra of hexagonal Cd(OH)2, CdOHCl, and CdOHF, along with deuterated analogues CdODCl and CdODF, in the range 2.5–16 μ are reported for the first time. The effects of substituting a halogen for an OH group in Cd(OH)2 are (i) shift of OH stretching vibration to a lower frequency and (ii) appearance of strong absorption bands in the region 8–16 μ. All the observed bands in the deuterated analogues are displaced to lower frequencies with νH/νd ratios between 1.35–1.37. The spectra of CdOHCl and CdOHF show a high correlation with their zinc analogues and although both spectra appear consistent with a simple molecule of Cs or C1 symmetry, an alternate interpretation is given in terms of OH lattice vibrations.

The influence of pressure on the infrared spectra of hydrogen-bonded solids. V. The formation of Fermi resonance 'windows'

1977 ◽  
Vol 30 (1) ◽  
pp. 71 ◽  
Author(s):  
SD Hamann
Keyword(s):  
Infrared Spectra ◽  
Isonicotinic Acid ◽  
Wave Functions ◽  
Fermi Resonance ◽  
Absorption Bands ◽  
Bending Vibrations ◽  
Low Frequencies ◽  
Stretching Vibrations ◽  
Solid Compounds ◽  
Smooth Transformation

Measurements have been made of the influence of pressure to 40 kbar on the infrared spectra of the normal and X-deuterated forms of seven solid compounds which have strong X-H...Y hydrogen bonds and whose spectra show very broad and intense X-H stretching bands at low frequencies. For two of the compounds, isonicotinic acid and nicotinic acid, compression causes the smooth transformation of superimposed absorption bands into Fermi resonance 'windows', or 'Evans holes'. The effect probably arises from increased overlap of the wave functions for in-plane ring-bending vibrations and X-H stretching vibrations.

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