Studies on the interaction of selenite and selenium with sulphur donors. Part 4. Thiosulfate

1996 ◽  
Vol 74 (5) ◽  
pp. 753-759 ◽  
Author(s):  
Shermin Rahim ◽  
John Milne
Keyword(s):  
Raman Spectroscopy ◽  
Nmr Spectroscopy ◽  
Key Words ◽  
Bond Formation ◽  
Acid Solutions ◽  
Linkage Isomers ◽  
Linkage Isomerism ◽  
Selenous Acid ◽  
Direct Attack ◽  
Incoming Ligand

Raman and Se-77 NMR spectroscopy confirm that when selenous acid is reduced by thiosulfate in water selenopentathionate and tetrathionate are formed.[Formula: see text]Depending upon the stoichiometry and pH, two isomers of the selenopentathionate ion, O- and S-bonded, are formed. Insufficiently acid solutions cause decomposition to selenium and tetrathionate ion.[Formula: see text]Fresh solutions prepared from crystalline sodium selenopentathionate and water undergo slow decompositon. NMR and Raman spectra show the presence of both the O-bonded and S-bonded linkage isomers. The O-bonded isomer facilitates the formation of tetrathionate. Addition of thiosulfate to selenotrithionate solution or sulfite to selenopentathionate solution yields trithionate with no indication of dithionate or tetrathionate formation. This suggests that simple S—S bond formation at selenium does not occur but that there may be direct attack of the incoming ligand on the attached ligand. Key words: selenite, thiosulfate, selenopentathionate, Se-77 NMR, Raman spectroscopy, linkage isomerism.

Studies on the interaction of selenite and selenium with sulphur donors. Part 5. Thiocyanate

1996 ◽  
Vol 74 (10) ◽  
pp. 1889-1895 ◽  
Author(s):  
Christopher Milne ◽  
John Milne
Keyword(s):  
Raman Spectroscopy ◽  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chemical Exchange ◽  
Acid Oxidation ◽  
Relaxation Processes ◽  
Line Broadening ◽  
Linkage Isomerism ◽  
Selenous Acid ◽  
Scalar Relaxation

The oxidation of thiocyanic acid by selenous acid has been shown to take place in an analogous way to that found for selenous acid oxidation of most thiols and thiolates to give the corresponding selenotrisulfide and disulfide products[Formula: see text]The products of this reaction have been studied by IR, Raman, and Se-77, C-13, and N-15 NMR spectroscopy. The vibrational spectra of the solid Se(SCN)2 have been assigned based on S-bonded thiocyanate ligands and, through NMR and vibrational spectroscopy, both this linkage isomer and the isomer with N- and S-bonded thiocyanate have been identified and characterized in solutions of Se(SCN)2. A complex combination of scalar relaxation processes, involving chemical exchange and quadrupolar effects, accounts for the line broadening observed in the carbon-13 NMR spectra. Key words: selenite, thiocyanate, selenium dithiocyanate, Se-77, N-15, and C-13 NMR; Raman spectroscopy; linkage isomerism

Hexachlorotellurate(IV) hydrolysis equilibria in hydrochloric acid. Measurement by Raman and 125Te NMR spectroscopy and a reconsideration of earlier spectrophotometric results

1991 ◽  
Vol 69 (6) ◽  
pp. 987-992 ◽  
Author(s):  
J. B. Milne
Keyword(s):  
Raman Spectroscopy ◽  
Nmr Spectroscopy ◽  
Hydrochloric Acid ◽  
Key Words ◽  
Nmr Spectra ◽  
Ion Pairing ◽  
Hydrolysis Constant ◽  
Visible Spectrophotometry ◽  
Hydrolysis Constants ◽  
Uv Visible

Solutions of TeO2 (0.001 M) in HCl over a range of concentrations are shown to contain TeCl2(OH)2 in addition to TeCl62−and TeCl4(OH)−. The hydrolysis constants for TeCl62− and TeCl4(OH)− have been determined from a reconsideration of earlier UV-visible spectrophotometric results (1)[Formula: see text]The hydrolysis constants have also been determined by quantitative Raman spectroscopy (K1 = 2.21 (± 0.16) × 104 M3; K2 = 442 ± 57 M3). The agreement between K2 determined by the two methods is good but K1 from spectrophotometry is much larger than that from Raman studies. This disagreement is attributed to ion-pairing which will be significant at the concentration at which the Raman measurements were made (c(TeO2) = 0.50 M). The hydrolysis constant for TeCl62− was also determined from the 125Te NMR spectra of TeO2/HCl solutions, which consisted of one signal, indicating rapid Te exchange between all species. The hydrolysis constant, determined in this way (K1 = 1.92 (± 0.07) × 104 M3) was also low compared to that determined from spectrophotometry. Key words: solution, equilibria, tellurium, hydrochloric acid, Raman spectroscopy, 125Te NMR spectroscopy, UV–visible spectrophotometry.

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.

Nature of Monomeric Molybdenum(VI) Cations in Acid Solutions Using Theoretical Calculations and Raman Spectroscopy

2019 ◽  
Vol 123 (15) ◽  
pp. 3304-3311 ◽  
Author(s):  
Ning Zhang ◽  
Erich Königsberger ◽  
Siqi Duan ◽  
Ke Lin ◽  
Haibo Yi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Theoretical Calculations ◽  
Acid Solutions

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.

A kinetic study of mechanochemical halogen bond formation by in situ31P solid-state NMR spectroscopy

2017 ◽  
Vol 53 (71) ◽  
pp. 9930-9933 ◽  
Author(s):  
Yijue Xu ◽  
Lysiane Champion ◽  
Bulat Gabidullin ◽  
David L. Bryce
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Kinetic Study ◽  
Solid State Nmr ◽  
Halogen Bond ◽  
Bond Formation ◽  
Nmr Studies ◽  
Solid State Nmr Spectroscopy

In situ 31P solid-state NMR studies of mechanochemical halogen bond formation provide insights into the cocrystallisation process and an estimate of the activation energy.

Tracking Photoinduced Au–Au Bond Formation through Transient Terahertz Vibrations Observed by Femtosecond Time-Domain Raman Spectroscopy

2019 ◽  
Vol 141 (49) ◽  
pp. 19296-19303 ◽  
Author(s):  
Hikaru Kuramochi ◽  
Satoshi Takeuchi ◽  
Munetaka Iwamura ◽  
Koichi Nozaki ◽  
Tahei Tahara
Keyword(s):  
Raman Spectroscopy ◽  
Time Domain ◽  
Bond Formation

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.

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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