Integral intensities of the IR bands of the stretching vibrations of the NH, C=O, and C=C groups in theVinca alkaloids

1966 ◽  
Vol 2 (3) ◽  
pp. 147-153
Author(s):  
M. R. Yagudaev
Keyword(s):  
Stretching Vibrations ◽  
Ir Bands

Vibrational study and spectra-structure correlations in magnesium disaccharinate heptahydrate, Mg(sac)2⋅7H2O

2008 ◽  
Vol 27 (1) ◽  
pp. 1
Author(s):  
Gligor Jovanovski ◽  
Petre Makreski ◽  
Bojan Šoptrajanov
Keyword(s):  
Experimental Data ◽  
Raman Spectrum ◽  
The Other ◽  
Water Molecules ◽  
Carbonyl Groups ◽  
Structural Units ◽  
Vibrational Study ◽  
Structure Correlations ◽  
Stretching Vibrations ◽  
Ir Bands

Infrared and Raman vibrational spectra of magnesium disaccharinate heptahydrate, Mg(sac)2⋅7H2O, in the 4000–380 cm–1 region (for infrared) and 4000–100 cm–1 region (for Raman) were studied. The assignment of the spectra was based on the experimental data for the previously studied metal saccharinates as well as the literature data for the ab initio calculations on the free deprotonated saccharinato species. Special attention was paid to the analysis of the H2O, CO and SO2 stretching modes. The spectral picture in the regions of the water, carbonyl and sulfonyl stretches is correlated with the number of the crystallographically determined non-equivalent H2O, CO and SO2 structural units. It was found that the presence of seven crystallographically different water molecules in the structure (fourteen different Ow⋅⋅⋅O and Ow⋅⋅⋅N distances) is not reflected in the appearance of the expected fourteen IR bands in the region of the OD stretching vibrations of the isotopically isolated HDO molecules. This must be due to the existence in the structure of several Ow⋅⋅⋅O or Ow⋅⋅⋅N hydrogen bonds with very similar strengths causing an overlap of the corresponding bands in the spectrum. Despite the presence of two carbonyl groups with practically identical C–O distances [124.2(3) and 124.0(3) pm], two clearly separated bands are registered in the carbonyl stretching region of the IR (1660 and 1627 cm–1) and Raman spectrum (1648 and 1620 cm–1). On the other hand, although two nonequivalent SO2 groups are present in the structure of Mg(sac)2⋅7H2O, only one pair of bands due to SO2 stretchings [νas(SO2 and νs(SO2) modes] is registered in the IR spectrum.

Intensities of IR bands of CH stretching vibrations and atomic charges in saturated three-membered rings

1989 ◽  
Vol 25 (12) ◽  
pp. 1342-1348
Author(s):  
I. F. Tupitsyn ◽  
Yu. V. Puzanov ◽  
A. Yu. Shibaev ◽  
A. A. Kane ◽  
S. A. Egorov
Keyword(s):  
Atomic Charges ◽  
Stretching Vibrations ◽  
Ir Bands

Raman and infrared spectroscopic study of the vivianite-group phosphates vivianite, baricite and bobierrite

2002 ◽  
Vol 66 (6) ◽  
pp. 1063-1073 ◽  
Author(s):  
R. L. Frost ◽  
W. Martens ◽  
P. A. Williams ◽  
J. T. Kloprogge
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bonding ◽  
Water Molecules ◽  
Infrared Spectroscopic Study ◽  
Tetrahedral Symmetry ◽  
Phosphate Anions ◽  
Stretching Vibrations ◽  
Bending Modes ◽  
Ir Bands ◽  
Hydrogen Bonded

Abstract The molecular structure of the three vivianite-structure, compositionally related phosphate minerals vivianite, baricite and bobierrite of formula M32+(PO4)2.8H2O where M is Fe or Mg, has been assessed using a combination of Raman and infrared (IR) spectroscopy. The Raman spectra of the hydroxyl-stretching region are complex with overlapping broad bands. Hydroxyl stretching vibrations are identified at 3460, 3281, 3104 and 3012 cm−1 for vivianite. The high wavenumber band is attributed to the presence of FeOH groups. This complexity is reflected in the water HOH-bending modes where a strong IR band centred around 1660 cm−1 is found. Such a band reflects the strong hydrogen bonding of the water molecules to the phosphate anions in adjacent layers. Spectra show three distinct OH-bending bands fromstrongly hydrogen-bonded, weakly hydrogen bonded water and non-hydrogen bonded water. The Raman phosphate PO-stretching region shows strong similarity between the three minerals. In the IR spectra, complexity exists with multiple antisymmetric stretching vibrations observed, due to the reduced tetrahedral symmetry. This loss of degeneracy is also reflected in the bending modes. Strong IR bands around 800 cm−1 are attributed to water librational modes. The spectra of the three minerals display similarities due to their compositions and crystal structures, but sufficient subtle differences exist for the spectra to be useful in distinguishing the species.

scholarly journals IR-Spectroscopic Study of Complex Formation of Nitrogen Oxides (NO, N2O) with Cationic Forms of Zeolites and the Reactivity of Adsorbed Species in CO and CH4 Oxidation

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 55
Author(s):  
Alexander L. Kustov ◽  
Leonid M. Kustov
Keyword(s):  
Nitrogen Oxides ◽  
Molecular Form ◽  
Specific Geometry ◽  
Adsorption Of Co ◽  
Stretching Vibrations ◽  
Charge And Radius ◽  
Combination Bands ◽  
Ir Spectroscopic ◽  
Ir Bands ◽  
Formation Of Complexes

The formation of complexes and disproportionation of nitrogen oxides (NO, N2O) on cationic forms of LTA, FAU, and MOR zeolites was investigated by diffuse-reflectance IR spectroscopy. N2O is adsorbed on the samples under study in the molecular form and the frequencies of the first overtone of the stretching vibrations ν10–2 and the combination bands of the stretching vibrations with other vibrational modes for N2O complexes with cationic sites in zeolites (ν30–1 + ν10–1, ν10–1 + δ0–2) are more significantly influenced by the nature of the zeolite. The presence of several IR bands in the region of 2400–2600 cm−1 (the ν10–1 + δ0–2 transitions) for different zeolite types was explained by the availability of different localization sites for cations in these zeolites. The frequencies in this region also depend on the nature of the cation (its charge and radius). The data can be explained by the specific geometry of the N2O complex formed, presumably two-point adsorption of N2O on a cation and a neighboring oxygen atom of the framework. Adsorption of CO or CH4 on the samples with preliminarily adsorbed N2O at 20–180 °C does not result in any oxidation of these molecules. NO+ and N2O3 species formed by disproportionation of NO are capable of oxidizing CO and CH4 molecules to CO2, whereas NOx is reduced simultaneously to N2 or N2O. The peculiarities in the behavior of cationic forms of different zeolites with respect to adsorbed nitrogen oxides determined by different density and localization of cations have been established.

Schwingungsspektren und Normalkoordinatenanalyse der heteroleptischen Halogenohexaborate B6XnY6-n2-, n = 1-5; Χ ≠ Υ = Cl, Br, I / Vibrational Spectra and Normal Coordinate Analysis of the Heteroleptic Halogenohexaborates B6XnY6-n2-, n = 1— 5; Χ ≠ Y = Cl, Br, I

1991 ◽  
Vol 46 (5) ◽  
pp. 602-608 ◽  
Author(s):  
J. Thesing ◽  
M. Stallbaum ◽  
W. Preetz
Keyword(s):  
Potential Energy Distribution ◽  
Site Symmetry ◽  
Geometric Isomers ◽  
Normal Coordinate ◽  
Vibrational Coupling ◽  
Valence Force Field ◽  
Stretching Vibrations ◽  
Ir And Raman ◽  
Ir Bands ◽  
Good Agreement

Normal coordinate analyses for the 24 mixed halogenohexaborates B6XnY6-n2-, n = 1—5, Χ ≠ Y = Cl, Br, I, including the pairs of geometric isomers for n = 2, 3, 4 have been performed, based on a general valence force field. Using the bond lengths and force constants for the homoleptic species B6X62-, which with respect to the B6 cage are weighted standardized, the calculated frequencies are in good agreement with observed IR and Raman bands. The boronhalogen stretching vibrations for symmetric molecular axes correspond with the Ra(IR) bands of the homoleptic compounds: ClB6Cl 327 (515), BrB6Br 207 (430), IB6I 152 (394) cm-1. As a characteristic feature the mixed halogeno clusters exhibit bands with nearly averaged frequencies from asymmetrical axes: ClB6Br 261 (487), ClB6I 227 (473), BrB6I 178 (409) cm-1. This complete vibrational coupling is confirmed by properly balanced potential energy distribution on BX and BY bonds. There is a slight influence of the different substituents on the internal modes of the B6 cage (pseudo-Oh), observed in the sequence A1g>T1u> Eg>T2g in the region 1220-740 cm-1. The bands are shifted about 100 cm-1 with increasing mass of halogen, broadened by boron isotopomers (max. 60 cm-1), and degenerate vibrations are split by lowered point and site symmetry up to 100 cm-1.

Infrared spectra and substituent effects in 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones

1983 ◽  
Vol 48 (2) ◽  
pp. 586-595 ◽  
Author(s):  
Alexander Perjéssy ◽  
Pavol Hrnčiar ◽  
Ján Šraga
Keyword(s):  
Substituent Effects ◽  
Phenyl Group ◽  
Wave Number ◽  
Vibrational Coupling ◽  
Wave Numbers ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The Relationship ◽  
Derivatives Of ◽  
Effect Of Structure

The wave numbers of the fundamental C=O and C=C stretching vibrations, as well as that of the first overtone of C=O stretching vibration of 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones and 1,3-cycloheptanedione were measured in tetrachloromethane and chloroform. The spectral data were correlated with σ+ constants of substituents attached to phenyl group and with wave number shifts of the C=O stretching vibration of substituted acetophenones. The slope of the linear dependence ν vs ν+ of the C=C stretching vibration of the ethylenic group was found to be more than two times higher than that of the analogous correlation of the C=O stretching vibration. Positive values of anharmonicity for asymmetric C=O stretching vibration can be considered as an evidence of the vibrational coupling in a cyclic 1,3-dicarbonyl system similarly, as with derivatives of 1,3-indanedione. The relationship between the wave numbers of the symmetric and asymmetric C=O stretching vibrations indicates that the effect of structure upon both vibrations is symmetric. The vibrational coupling in 1,3-cycloheptanediones and the application of Seth-Paul-Van-Duyse equation is discussed in relation to analogous results obtained for other cyclic 1,3-dicarbonyl compounds.

Dipole Moments of para-Substituted N-Phenylsulfonyl-N'-Allylthioureas

1995 ◽  
Vol 60 (5) ◽  
pp. 856-862
Author(s):  
Gejza Suchár ◽  
Ivan Danihel
Keyword(s):  
Dipole Moments ◽  
Vector Addition ◽  
Stretching Vibrations

Dipole moments of a series of para-substituted N-phenylsulfonyl-N'-allylthioureas were determined. Comparison of the experimentally found dipole moments with those calculated by vector addition of bond and group moments has shown that (E) conformation at the N-C bonds is preferred. The same result was obtained from the N-H stretching vibrations. The results are compatible with a synperiplanar arrangement at the C-C bond of the allyl moiety.

Vibrational spectra of aquadioxotetra; peroxodivanadates(V) M2[V2O2(O2)4(H2O)]·xH2O (M = N(CH3)4, Cs)

1990 ◽  
Vol 55 (6) ◽  
pp. 1485-1490 ◽  
Author(s):  
Peter Schwendt ◽  
Milan Sýkora
Keyword(s):  
Raman Spectra ◽  
Vibrational Spectra ◽  
Normal Coordinate Analysis ◽  
Force Constants ◽  
Infrared And Raman Spectra ◽  
Empirical Correlations ◽  
Normal Coordinate ◽  
Bond Lengths ◽  
Stretching Vibrations

The infrared and Raman spectra of M2[V2O2(O2)4(H2O)]·xH2O and M2[V2O2(O2)4(D2O)]·xD2O (M = N(CH3)4, Cs) were measured. In the region of the vanadium-oxygen stretching vibrations, the spectra were interpreted based on normal coordinate analysis, employing empirical correlations between the bond lengths and force constants.

scholarly journals Copper(II) 2,2-Bis(Hydroxymethyl)Propionate Coordination Compounds with Hexamethylenetetramine: From Mononuclear Complex to One-Dimensional Coordination Polymer

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3358
Author(s):  
Sadaf Rauf ◽  
Agata Trzesowska-Kruszynska ◽  
Tomasz Sierański ◽  
Marcin Świątkowski
Keyword(s):  
Coordination Polymer ◽  
Coordination Compounds ◽  
Structural Diversity ◽  
Structural Features ◽  
Mononuclear Complex ◽  
Molar Ratio ◽  
One Dimensional ◽  
1D Coordination Polymer ◽  
Copper Coordination ◽  
Stretching Vibrations

Three new copper coordination compounds derived from 2,2-bis(hydroxymethyl)propionic acid (dmpa) and hexamethylenetetramine (hmta) were obtained and their crystal structures were determined. The stoichiometry of the reagents applied in the syntheses reflects the metal to ligand molar ratio in the formed solid products. Due to the multiple coordination modes of the used ligands, wide structural diversity was achieved among synthesized compounds, i.e., mononuclear [Cu(dmp)2(hmta)2(H2O)] (1), dinuclear [Cu2(dmp)4(hmta)2] (2), and 1D coordination polymer [Cu2(dmp)4(hmta)]n (3). Their supramolecular structures are governed by O—H•••O and O—H•••N hydrogen bonds. The compounds were characterized in terms of absorption (UV-Vis and IR) and thermal properties. The relationships between structural features and properties were discussed in detail. Owing to discrepancies in the coordination mode of a dmp ligand, bidentate chelating in 1, and bidentate bridging in 2 and 3, there is a noticeable change in the position of the bands corresponding to the stretching vibrations of the carboxylate group in the IR spectra. The differences in the structures of the compounds are also reflected in the nature and position of the UV-Vis absorption maxima, which are located at lower wavelengths for 1.

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