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.

closo-Halogenohydrohexaborate, IV Protonierung, Deuterierung und Schwingungsspektren von claso-Hexaboraten / closo-Halogenohydrohexaborate, IV Protonation, Deuteration and Vibrational Spectra of closo-Hexaborates

1988 ◽  
Vol 43 (10) ◽  
pp. 1319-1326 ◽  
Author(s):  
W Preetz ◽  
A Heinrich ◽  
J Thesing
Keyword(s):  
Activation Energy ◽  
Frequency Shift ◽  
Vibrational Spectra ◽  
High Frequency ◽  
Alkaline Solutions ◽  
Lower Symmetry ◽  
High Frequency Shift ◽  
Stretching Vibrations ◽  
Ph Dependent ◽  
Ir And Raman

The weak Brönsted acids B6H7- and XB6H6-, X = Cl, Br, I; pka : 7-4,75, are formed by protonation of B6H62- and XB6H52- respectively. The deuteration rates, evaluated from integrated IR band intensities of the BH and BD stretching vibrations, are linearly dependent on the mole fractions of the protonated species, and decrease with increasing degree of halogenation in the series Cl>Br>I. H atoms trans-positioned to halogens are exchanged 100 times more rapidly than the remaining ones. The activation energy for the H/D exchange amounts to 76 ± 1,5 kJ/mol for B6H7-. The lower symmetry of the protonated borates is evident from additional IR and Raman bands. They are distinguished from the corresponding Brönsted bases by a high frequency shift of the BH stretching vibrations in the order of 100 cm-1. Due to the pH dependent equilibrium B6H62-/B6H7- and different solubilities of the tetrabutylammonium salts, the separation of B6H62-/B12H122- mixtures is achievable. In alkaline solutions the very soluble B6H62- is present, whereas (TBA)2B12H12 precipitates quantitatively. By subsequent cautious acidification of the supernatant, insoluble (TBA)B6H7 is obtained.

Die Schwingungsspektren der Silylanionen (SiH3)nSiH⊖3-n und (SiD3)nSiD⊖3-n / Vibrational Spectra of the Silyl Anions (SiH3)nSiH⊖3-n and (SiD3)nSiD⊖3-n

1974 ◽  
Vol 29 (9-10) ◽  
pp. 647-653 ◽  
Author(s):  
Hans Bürger ◽  
Reint Eujen
Keyword(s):  
Raman Spectra ◽  
Vibrational Spectra ◽  
Negative Charge ◽  
Lone Pair ◽  
Normal Coordinate Analysis ◽  
Ir And Raman Spectra ◽  
Normal Coordinate ◽  
Normal Vibrations ◽  
Stretching Vibrations ◽  
Ir And Raman

The IR and Raman spectra of SiH3⊖, SiH3SiH2⊖, (SiH3)2SiH⊖, (SiH3)3Si⊖ and their deuterated derivatives have been recorded in HMPT and HMPT-d18 solutions. Most normal vibrations have been identified. The SiH and SiSi stretching vibrations are considerably lower than for analogous silanes and silylphosphines, ∼ 2050 and 1850-1900 cm-1 being characteristic for SiH3 and SiH⊖n groups respectively. The assignments are proved by a normal coordinate analysis, and force constants have been calculated. The negative charge is mainly localized on the trivalent Si atom and the lone pair acts repulsively rather than strengthening the SiSi bond through (p→d)π effects.

scholarly journals Комбинационное рассеяние света в эвтектическом композите InSb-MnSb

2020 ◽  
Vol 54 (4) ◽  
pp. 341
Author(s):  
И.Х. Мамедов ◽  
Д.Г. Араслы ◽  
Р.Н. Рагимов ◽  
А.А. Халилова
Keyword(s):  
Thin Films ◽  
Frequency Shift ◽  
Raman Spectra ◽  
High Frequency ◽  
Theoretical Data ◽  
Eutectic Composite ◽  
Flash Evaporation ◽  
Evaporation Method ◽  
The Matrix ◽  
High Frequency Shift

Raman spectra of bulk samples of the InSb-MnSb eutectic composite and their thin films prepared by the flash evaporation method have been studied. In the Raman spectra observed TO and LO modes at frequencies of 179.5 cm-1 and 192.4 cm-1 correspond to InSb compound and also the peaks at frequencies 122 cm-1, 127 cm-1, 167 cm-1, 211 cm-1, 245.5 cm-1 correspond to theoretical data for MnSb as is well known from literature. The TO mode in the Raman spectra for films is shifted toward lower energies (178 cm-1), but the LO mode is higher (196 cm-1). The high-frequency shift of the LO mode in the composite with compared its value for InSb is probably due to the presence of deformation at the matrix-inclusion interface, as well as the contribution by surface phonons scattering.

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.

Chemical adsorption of salicylate on silver - A systematic approach to the interpretation of surface-enhanced vibrational spectra

2004 ◽  
Vol 82 (6) ◽  
pp. 987-997 ◽  
Author(s):  
P J.G Goulet ◽  
R F Aroca
Keyword(s):  
Salicylic Acid ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Density Functional ◽  
Ir And Raman Spectra ◽  
Chemical Adsorption ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
Ir And Raman

In this work, surface-enhanced vibrational spectroscopy and normal vibrational spectroscopy as well as density functional theory (DFT) computational methods have been employed to investigate the nature of the chemical adsorption and orientation of the surface species generated from salicylic acid at silver surfaces. The structure of salicylic acid and its IR and Raman spectra are determined at the B3LYP/6-311+G(d,p) level of theory. These results are used in the assignment of the vibrational spectra. Surface-enhanced Raman scattering (SERS) spectra obtained from silver island films thinly coated with salicylic acid confirm chemical adsorption on the Ag nanostructures. To probe the nature of this surface complex, the optimized geometries and IR and Raman spectra of two model salicylate-silver complexes (Ag1 and Ag2) were calculated at the B3LYP/Lanl2DZ level of theory. It was found that good agreement exists between experimentally observed SERS spectra and the simulated SERS spectra of a complex with the salicylate monoanion bound to a Ag+ ion through its carboxylate group (Ag1). The carboxylate silver salt of salicylic acid (essentially the Ag1 complex) was also prepared, and its IR and Raman spectra were recorded for comparison with the surface-enhanced vibrational spectra. These results, along with the application of surface selection rules, suggest that salicylic acid is deprotonated at silver surfaces, interacting through its carboxylate group alone, and is preferentially in a tilted head-on orientation.Key words: chemisorption, salicylic acid, silver, density functional theory, surface-enhanced Raman scattering, reflection-absorption IR spectroscopy, surface-enhanced IR absorption.

Perfluormethyl-Element-Liganden, XI Die Schwingungsspektren von (CF3)2EMn(CO)5 (E=P, As) / Perfluoromethyl Element Ligands, XI. Vibrational Spectra of (CF3)2EMn(CO)5 (E = P, As)

1975 ◽  
Vol 30 (7-8) ◽  
pp. 539-543 ◽  
Author(s):  
Reinhard Demuth ◽  
Joseph Grobe ◽  
Robert Rau
Keyword(s):  
Liquid Phase ◽  
Force Field ◽  
Gas Phase ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Normal Coordinate Analysis ◽  
Ir And Raman Spectra ◽  
Normal Coordinate ◽  
Ir And Raman

The gas phase IR and liquid phase IR and Raman spectra of (CF3)2PMn(CO)5 and (CF3)2AsMn(CO)6 have been recorded. The spectra are assigned on the basis of a normal coordinate analysis using a transferred force field.

Ab initio spectroscopy of water under electric fields

2019 ◽  
Vol 21 (38) ◽  
pp. 21205-21212 ◽  
Author(s):  
Giuseppe Cassone ◽  
Jiri Sponer ◽  
Sebastiano Trusso ◽  
Franz Saija
Keyword(s):  
Ab Initio ◽  
Raman Spectra ◽  
Electric Fields ◽  
Liquid Water ◽  
High Frequency ◽  
Water Structure ◽  
Ir And Raman Spectra ◽  
Bulk Liquid ◽  
Librational Mode ◽  
Ir And Raman

IR and Raman spectra of bulk liquid water under intense electric fields reveal the contraction of both spectra and the onset of a novel high-frequency librational mode band. Moreover, the water structure evolves toward “ice-like” arrangements.

Darstellung und Eigenschaften des Tetrabutylammonium-iso-oktamolybdats [N(C4H9)4] 4Mo8O26 / Preparation and Properties of Tetrabutylammonium iso-octamolybdate [N(C4H9)4]4Mo8O26

1977 ◽  
Vol 32 (8) ◽  
pp. 853-857 ◽  
Author(s):  
Joachim Fuchs ◽  
Irene Brüdgam
Keyword(s):  
Single Crystals ◽  
Raman Spectra ◽  
Organic Solvents ◽  
Uv Spectroscopy ◽  
Sodium Molybdate ◽  
Ir And Raman Spectra ◽  
Ion Formation ◽  
Ir And Raman

From weakly acidified solutions of sodium molybdate by addition of tetrabutylammonium ions an iso-octamolybdate [N(C4H9)4]4Mo8 O26 is formed whose anion has a structure different from the known alkali or ammonium octamolybdates. Single crystals are obtainable by reaction in organic solvents. The IR and Raman spectra are presented. The decomposition of the anion by aging in dichloroethane in solution was investigated by UV spectroscopy. This study offers new aspects concerning the mechanism of polymolybdate ion formation.

Darstellung, Eigenschaften und Schwingungsspektren von MoVO2(O2PCl2) · POCl3 und MoO2Cl2 · POCl3 / Preparations, Chemical Properties and the Vibrational Spectra of MoVO2(O2PCl2) · POCl3 und MoO2Cl2 · POCl3

1973 ◽  
Vol 28 (3-4) ◽  
pp. 148-152 ◽  
Author(s):  
K. Dehnicke ◽  
A.-F. Shihada
Keyword(s):  
Raman Spectra ◽  
Vibrational Spectra ◽  
Magnetic Measurements ◽  
Chemical Properties ◽  
Ir And Raman Spectra ◽  
Ir And Raman

Polymeric MoO2 (O2PCl2) · POCl3 1 is obtained by the reaction of MoCl5 and P2O3Cl4, while MoO2Cl2 · POCl3 2 is formed by passage of Cl2O into a solution of MoCl5 in POCl3. From magnetic measurements and IR data it appears that 1 contains no Mo-O-Mo system but Mo-O-P-O-Mo bridges. The IR and RAMAN spectra of 2 were assigned by comparison with the spectrum of MoO2Cl2 · H2O.

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