The disproportionation of diselenium dichloride, Se2Cl2, and diselenium dibromide, Se2Br2

1989 ◽  
Vol 67 (11) ◽  
pp. 1936-1941 ◽  
Author(s):  
Marc Lamoureux ◽  
John Milne
Keyword(s):  
Raman Spectroscopy ◽  
Nmr Spectroscopy ◽  
Vibrational Spectra ◽  
Equilibrium Constants ◽  
Combination Bands

Diselenium dichloride and dibromide have been shown by Raman and 77Se-nmr spectroscopy to be equilibrium mixtures of Se2X2 and small amounts of SeX2 and SenX2. Equilibrium constants have been estimated for the disproportionation reactions,[Formula: see text]The origin of "spurious" peaks in the reported vibrational spectra of Se2Br2 and Se2Cl2, which have been variously assigned to overtone and combination bands and impurities has been clarified. Mixtures of Se2Br2 and Se2Cl2 are shown to contain Se2BrCl in equilibrium according to[Formula: see text]Keywords: 77Se nmr, Raman spectroscopy, selenium halides, diselenium dichloride, diselenium dibromide.

scholarly journals Barium Titanium Oxynitride from Ammonia-Free Nitridation of Reduced BaTiO3

Inorganics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 62
Author(s):  
Hua Guo ◽  
Aleksander Jaworski ◽  
Zheng Chen ◽  
Can Lu ◽  
Adam Slabon ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Nmr Spectroscopy ◽  
Transition Metal ◽  
Signal Intensity ◽  
Diffuse Reflectance ◽  
Conduction Band Edge ◽  
Vacancy Ordering ◽  
Vis Spectroscopy ◽  
O Vacancy ◽  
Barium Titanium

We investigated the nitridation of reduced BaTiO3, BaTiO2.60H0.08, corresponding to an oxyhydride with a large concentration of O defects (>10%). The material is readily nitrided under flowing N2 gas at temperatures between 400 and 450 °C to yield oxynitrides BaTiO2.6Nx (x = 0.2−0.22) with a slightly tetragonally distorted perovskite structure, a ≈ 4.01 and c ≈ 4.02 Å, and Ti partially remaining in the oxidation state III. The tetragonal structure was confirmed from Raman spectroscopy. 14N MAS NMR spectroscopy shows a single resonance at 270 ppm, which is typical for perovskite transition metal oxynitrides. However, largely different signal intensity for materials with very similar N content suggests N/O/vacancy ordering when prolonging nitridation times to hours. Diffuse reflectance UV-VIS spectroscopy shows a reduction of the intrinsic band gap to 2.4–2.45 eV compared to BaTiO3 (~3.2 eV). Mott-Schottky measurements confirm n-type conductivity and reveal a slight negative shift of the conduction band edge from –0.59 V (BaTiO3) to ~–0.65 eV.

Anharmonic Coupling Revealed by the Vibrational Spectra of Solvated Protonated Methanol: Fermi Resonance, Combination Bands, and Isotope Effect

2021 ◽  
Vol 125 (9) ◽  
pp. 1910-1918
Author(s):  
Chih-Kai Lin ◽  
Qian-Rui Huang ◽  
Ying-Cheng Li ◽  
Ha-Quyen Nguyen ◽  
Jer-Lai Kuo ◽  
...  
Keyword(s):  
Isotope Effect ◽  
Vibrational Spectra ◽  
Fermi Resonance ◽  
Anharmonic Coupling ◽  
Combination Bands

scholarly journals pKa Determination of a Histidine Residue in a Short Peptide Using Raman Spectroscopy

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 405 ◽  
Author(s):  
Brett H. Pogostin ◽  
Anders Malmendal ◽  
Casey H. Londergan ◽  
Karin S. Åkerfeldt
Keyword(s):  
Raman Spectroscopy ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Peptide Sequence ◽  
Short Peptide ◽  
Dependent Behavior ◽  
Pka Determination ◽  
Key Functional Groups

Determining the pKa of key functional groups is critical to understanding the pH-dependent behavior of biological proteins and peptide-based biomaterials. Traditionally, 1H NMR spectroscopy has been used to determine the pKa of amino acids; however, for larger molecules and aggregating systems, this method can be practically impossible. Previous studies concluded that the C-D stretches in Raman are a useful alternative for determining the pKa of histidine residues. In this study, we report on the Raman application of the C2-D probe on histidine’s imidazole side chain to determining the pKa of histidine in a short peptide sequence. The pKa of the tripeptide was found via difference Raman spectroscopy to be 6.82, and this value was independently confirmed via 1H NMR spectroscopy on the same peptide. The C2-D probe was also compared to other Raman reporters of the protonation state of histidine and was determined to be more sensitive and reliable than other protonation-dependent signals. The C2-D Raman probe expands the tool box available to chemists interested in directly interrogating the pKa’s of histidine-containing peptide and protein systems.

Ligand scrambling reactions of cyano(thione)gold(I) complexes and determination of their equilibrium constants

2002 ◽  
Vol 80 (10) ◽  
pp. 1279-1284 ◽  
Author(s):  
Saeed Ahmad ◽  
Anvarhusein A Isab ◽  
Herman P Perzanowski
Keyword(s):  
Ionic Strength ◽  
Nmr Spectroscopy ◽  
Key Words ◽  
Equilibrium Constants ◽  
Solvent Polarity ◽  
Approach To Equilibrium ◽  
Initial Concentration ◽  
C Nmr

Ligand scrambling reactions in cyano(thione)gold(I) complexes ([>C=S-Au-CN]) to form [Au(>C=S)2]+ and [Au(CN)2]– species have been investigated for a series of thiones in DMSO using 13C and 15N NMR spectroscopy. Rapid approach to equilibrium occurred and resulted in distinct signals for the [>C=S-Au-CN] and [Au(CN)2]– complexes, both in 13C and 15N NMR. Equilibrium constants (Keq) were determined for scrambling of all the complexes by integrating the CN resonances in the 13C NMR recorded at 298 K. The influence of various factors (initial concentration, ionic strength, temperature, and solvent polarity) on the Keq value was examined for a representative complex (ImtAuCN (Imt = Imidazolidine-2-thione)).Key words: cyanogold(I) complexes, thiones, ligand scrambling, NMR, Keq.

Synthesis and vibrational spectra of complexes of small carboxylic acids with 18-crown-6

1985 ◽  
Vol 63 (7) ◽  
pp. 1457-1462 ◽  
Author(s):  
Rodrique Savoie ◽  
André Rodrigue ◽  
Marie Pigeon-Gosselin ◽  
Robert Chênevert
Keyword(s):  
Raman Spectroscopy ◽  
Carboxylic Acids ◽  
Vibrational Spectra ◽  
Acid Water ◽  
Neutral Component ◽  
Infrared And Raman Spectroscopy ◽  
O 18

The neutral-component complexes (HCOOH)3•(18-crown-6)2, (CH3COOH)2•18-crown-6, and various halogenated CH3COOH/18-crown-6 adducts have been isolated and studied by infrared and Raman spectroscopy. The halogenated (F, Cl, and Br) derivatives, which occur as (acid•water)x•18-crown-6(x = 1 or 2) adducts, probably have a structure which is similar to that of the known CH2(CN)COOH•H2O•18-crown-6 complex.

scholarly journals [HMIM][Br9]: a Room-temperature Ionic Liquid Based on a Polybromide Anion

2013 ◽  
Vol 68 (10) ◽  
pp. 1103-1107 ◽  
Author(s):  
Heike Haller ◽  
Michael Hog ◽  
Franziska Scholz ◽  
Harald Scherer ◽  
Ingo Krossing ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Raman Spectroscopy ◽  
Ionic Liquid ◽  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Room Temperature ◽  
High Electrical Conductivity ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
X Ray

[HMIM][Br9] ([HMIM]=1-hexyl-3-methylimidazolium) has been investigated by Raman spectroscopy, single-crystal X-ray diffraction and NMR spectroscopy. Conductivity measurements show a high electrical conductivity like other polybromides.

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