The effects of solvents on the stretching vibrations of the thiocyanate and isothiocyanate groups

1964 ◽  
Vol 17 (8) ◽  
pp. 838 ◽  
Author(s):  
RA Cummins
Keyword(s):  
Hydrogen Bond ◽  
Frequency Shift ◽  
Mixed Solvent ◽  
Intensity Change ◽  
Solute Interaction ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
Large Frequency ◽  
Phenyl Compounds

The frequency and intensity of the pseudo-antisymmetric -NCS stretching vibration and the -C≡N stretching vibration in -SCN have been measured for the methyl and phenyl compounds of both isomers in a range of solvents. It is shown that the intensity change in the thiocyanates follows a function of the Buckingham type, but that the change in the intensity of the isothiocyanates is complicated by a further effect which could be due to specific solvent/solute interaction. This interaction is reflected in the large frequency shift of the isothiocyanates whereas for the thiocyanates the shift is only very small. However, mixed-solvent studies indicate that the interaction is not strong enough to be classed as a hydrogen bond. Parallel solvent studies on the analogous vibration of the -NCO group indicate that this group, rather surprisingly, is barely solvent-sensitive at all.

Anharmonicity, solvent effects, and hydrogen bonding: NH stretching vibrations

1970 ◽  
Vol 48 (14) ◽  
pp. 2197-2203 ◽  
Author(s):  
A. Foldes ◽  
C. Sandorfy
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solvent Effects ◽  
Bond Formation ◽  
Hydrogen Bond Formation ◽  
Stretching Vibration ◽  
Solvent Shifts ◽  
Stretching Vibrations ◽  
Secondary Amides ◽  
Influence Of Solvent

The influence of solvent effects and hydrogen bond formation on the anharmonicity of the NH stretching vibration of simple secondary amides, lactams, anilides, indole, pyrrole, and imidazole have been studied; and the frequencies of the first and second overtones, their half widths and solvent shifts measured. The validity of Buckingham's theory is established in the case of inert solvents; whereas the second order perturbation treatments are shown to be inapplicable to the case of hydrogen bonding solvents. All NH stretching modes seem to exhibit the same anharmonic behavior which is very different from that of OH vibrations.

Infrared Spectroscopy and Hydrogen Bonding: Complexing of y-Butyrolactone with o-Cresol

1972 ◽  
Vol 27 (2) ◽  
pp. 221-228 ◽  
Author(s):  
G. Nagarajan
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Frequency Shift ◽  
Mixed Solvent ◽  
Formation Constants ◽  
Free Energies ◽  
Low Concentrations ◽  
Intensity Changes ◽  
Inert Solvent ◽  
Large Frequency

AbstractInvestigations to study the effect of different solvents on the frequency, intensity, and band width of the carbonyl band of y-butyrolactone were carried out on the basis of the mixed solvent techniques with carbon tetrachloride, being the inert solvent. The solvent used for such investigations is o-cresol. The results establish the existence of the 1 : 1 and 1 : 2 complexes at fairly low concentrations for the y-butyrolactone-o-cresol system. The formation constants for these complexes were determined and used to resolve the observed carbonyl bands into the spectra of individual complexes. The observed large frequency shift for the 1 : 2 complex favours a structure in which two molecules of o-cresol are directly bonded to the carbonyl group. The free energies of formation at 25 °C by using these formation constants show that the strength of the interaction increases in going from the 1 : 1 complex to the 1 :2 complex of the same y-butyrolactone-o-cresol system. These results have been discussed in relation to the frequency shift, intensity changes, and half width changes.

PROTONATED γ-PYRONES

1963 ◽  
Vol 41 (2) ◽  
pp. 505-514 ◽  
Author(s):  
Denys Cook
Keyword(s):  
Hydrogen Bond ◽  
Solid State ◽  
Hydrogen Atom ◽  
Oxygen Atom ◽  
Plane Deformation ◽  
Carbonyl Oxygen ◽  
Out Of Plane ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
Deformation Modes

The vibrational spectra of several salts of 4-pyrone and 2,6-dimethyl-4-pyrone have been measured in the solid state. Deuterium replacement has been used to identify motions of the hydrogen atom which is located on the carbonyl oxygen atom and forms a hydrogen bond with the anion.Bands due to OH stretching vibrations have been observed from 2086 cm−1 in the HCl salt to 3310 cm−1 in the hexachloroantimonate of 2,6-dimethyl-4-pyrone. In-plane hydrogen-deformation modes of the OH group have been found near 1300 cm−1 with a much smaller range in the different salts than the stretching vibration. For the 4-pyrone salts the OH stretching vibrations were at similar frequencies, and the in-plane hydrogen-deformation frequencies were close to 1340 cm−1. Bands due to the out-of-plane deformation were not observed.Aqueous solutions of 2,6-dimethyl-4-pyrone hydrochloride at various concentrations showed the presence of both protonated and neutral molecules.

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.

scholarly journals Distinguishing Features and Identification Criteria for K-Dioctahedral 1M Micas (Illite-Aluminoceladonite and Illite-Glauconite-Celadonite Series) from Middle-Infrared Spectroscopy Data

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 153 ◽  
Author(s):  
Bella B. Zviagina ◽  
Victor A. Drits ◽  
Olga V. Dorzhieva
Keyword(s):  
Infrared Region ◽  
Spectroscopy Data ◽  
Unit Cell Parameters ◽  
Cation Composition ◽  
Cell Parameters ◽  
Sharp Maximum ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
Middle Infrared ◽  
Distinguishing Features

A representative collection of K-dioctahedral 1M micas ranging in composition from (Mg, Fe)-poor illites to aluminoceladonites through Mg-rich illites (Fe-poor varieties) and from Fe-bearing, Mg-rich illites to celadonites through Fe-illites, Al-glauconites and glauconites (Fe-bearing varieties) was studied by Fourier-transform infrared (FTIR) spectroscopy in the middle-infrared region. Analysis and comparison of the relationships between the band positions and cation compositions of Fe-poor and Fe-bearing K-dioctahedral micas provided a generalized set of FTIR identification criteria that include the band positions and profiles in the regions of Si–O bending, Si–O stretching, and OH-stretching vibrations. FTIR data allow unambiguous identification of illites, aluminoceladonites, and celadonites, as well as distinction between Fe-illites and illites proper, as well as between Al-glauconites and glauconites. Specifically, a sharp maximum from the AlOHMg stretching vibration at ~3600 cm−1, the presence of a MgOHMg stretching vibration at 3583–3585 cm−1, as well as characteristic band positions in the Si–O bending (435–439, 468–472 and 509–520 cm−1) and stretching regions (985–1012 and 1090–1112 cm−1) are clearly indicative of aluminoceladonite. The distinction between Fe-illites and Al-glauconites, which have similar FTIR features, requires data on cation composition and unit-cell parameters.

Die Schwingungsfeinstruktur der Elektronenspektren des 13C- und 18O-markierten trans-Dioxotetracyanoosmats (VI),[OsO2(CN)4]2 -

1988 ◽  
Vol 43 (3) ◽  
pp. 239-247 ◽  
Author(s):  
C. Sartori ◽  
W. Preetz
Keyword(s):  
Ground State ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Isotopic Shifts ◽  
Charge Transfer Transitions ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The One ◽  
Franck Condon ◽  
Electronic Ground

The electronic absorption spectrum of the solid tetramethyl-ammonium salt of [OsO2(CN)4]2 - is measured at 10 K. The five distinct band systems exhibit vibrational progressions in the range 660-750 cm - 1, corresponding to the Os = O stretching vibrations sometimes coupled with ν(OsC). From this vibrational fine structure the electronic origin is deduced and verified by characteristic isotopic shifts by 18O and 13C. The two bands at lowest energy are assigned to the d-d-transitions 1A1g [b22g] → 3Eg [b12g e1g] (620 - 460 nm) and 1A1g [b22g] → 1Eg [b12g e1g] (490 - 400 nm). The 3Eg state is split by spin-orbit coupling into 5 components, from the one at lowest energy a luminescence emission (830 - 670 nm) takes place with a progression of 860 cm-1, corresponding to the symmetric Os = O stretching vibration in the electronic ground state. The more intense bands are assigned to charge transfer transitions from oxo π-orbitals into unoccupied niveaus of Os (VI): 1A1g [e4u] → 3A2u [e3u e1g] (390 - 340); → 1A1u [e3u e1g] (340 - 290) and → 1Eu [e3u b11g (290 - 230 nm). The singlet-triplet distances are 3200-3600 cm - 1. From a Franck-Condon analysis an excited state elongation of 10-13 pm for the osmyl groups is calculated.

Darstellung und Schwingungsspektren von Alkyl-und Rhodanohydrohexaboraten / Preparation and Vibrational Spectra of Alkyl and Rhodano Hydrohexaborates

1988 ◽  
Vol 43 (10) ◽  
pp. 1327-1331 ◽  
Author(s):  
A Heinrich ◽  
W Preetz
Keyword(s):  
Frequency Shift ◽  
Raman Spectra ◽  
Organic Solvents ◽  
Vibrational Spectra ◽  
High Frequency ◽  
Acidity Constants ◽  
High Frequency Shift ◽  
Basic Solutions ◽  
Stretching Vibrations ◽  
Ir And Raman

Treatment of B6H62- with iodoalkanes and (SCN)2 in organic solvents affords the monosubstituted protonated hexaborates RB6H6-, R = CH3, C2H5< C3H7, C4H9, C8H17 and SCN, respectively. The acidity constants of these weak Brönsted acids range for the alkylated species from 8.8 to 9.6, and for R = SCN the pka value is ~5. From basic solutions the salts Cs2RB6H5 can be precipitated, which show band patterns in the IR and Raman spectra typical for monosubstituted hydrohexaborates. The protonated compounds RB6H6- are distinguished from the corresponding Brönsted bases RB6H52- by a high frequency shift of the BH stretching vibrations in the order of 100 cm-1. For Cs2(SCN)B6H5, S coordination of SCN- is supposed because of the high frequency of νCN: 2144 cm-1.

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