E.S.R. studies of the solute-solute interactions between copper(II) and nickel(II) thiosemicarbazone chelates in non-aqueous solutions

1976 ◽  
Vol 29 (12) ◽  
pp. 2583 ◽  
Author(s):  
JAD Bolfo ◽  
TD Smith ◽  
JF Boas ◽  
JR Pilbrow
Keyword(s):  
Organic Solvent ◽  
Aqueous Solutions ◽  
Ground State ◽  
Room Temperature ◽  
Profound Change ◽  
Frozen Solution ◽  
X Band ◽  
Show Evidence ◽  
Solute Interactions ◽  
Ligand Addition

The X-band e.s.r. spectra due to the copper(II) chelates of the thiosemicarbazones salicylaldehyde thiosemicarbazone (stsc), salicylaldehyde 4-methyl(thiosemicarbazone) (smtc), salicylaldehyde 4- ethyl-(thiosemicarbazone) (setc), salicylaldehyde 4- phenyl(thiosemicarbazone) (sptc), 2-hydroxyacetophen- one 4- ethyl(thiosemicarbazone) (aetc) and 2-hydroxypropiophenone 4- ethyl(thiosemicarbazone) (petc) dissolved in various organic solvents have been studied at room temperature and down to 77 K. The e.s.r. spectra show evidence of hyperfine structure due to the 14N nucleus of the ligand. Addition of the nickel(II) chelate of the thiosemicarbazone ligands to organic solvent solutions of the corresponding copper(II) chelate brings about a profound change in the e.s.r. spectrum of the copper(II) chelate in frozen solution. These changes are interpreted as arising from a change in the ground state of the copper(II) ion from essentially dx2-y2 to d3z2-r2, which arises as a result of specific solute- solute interactions between the copper(II) and nickel(II) chelates.

The cell-wall constituents of Apjohnia laetevirens Harvey

1969 ◽  
Vol 20 (2) ◽  
pp. 143 ◽  
Author(s):  
CM Stewart ◽  
CJ Dawes ◽  
BM Dickens ◽  
JWP Nicholls
Keyword(s):  
Cell Wall ◽  
Organic Solvent ◽  
Aqueous Solutions ◽  
Green Alga ◽  
Protein Complex ◽  
Cell Walls ◽  
Room Temperature ◽  
Organic Substances ◽  
Low Degree ◽  
Crystalline Aggregates

Cells of the green alga, Apjohnia laeterivens Harvey, have been ruptured in a Waring blendor in order to remove the majority of the protoplast from the cell-wall substances. The cell walls have been shown to contain, apart from extraneous protoplasmic constituents and some encrusting bryozoa, framework microfibrils of cellulose 1 which seem to be associated with pectin-like materials, arabinogalactan matrix substances and, perhaps, a polysaccharide-protein complex; these components appear to represent about 90% of the organic substances in the original organic-solvent extracted cell walls. Less than 25 % of the initial cellulose 1 was converted to cellulose 11 during treatments of several hours' duration at room temperature with aqueous solutions of 24% KOH and 17.5 % NaOH. The low degree of conversion is attributed to the presence of highly ordered and/or large "crystalline" aggregates of �-1,4'-glucan molecules in the cellulosic micelles of the framework microfibrils of the cell walls.

Stability of Aflatoxins in Solution

2012 ◽  
Vol 95 (4) ◽  
pp. 1084-1088 ◽  
Author(s):  
Gonzalo J Diaz ◽  
Sandra M Cepeda ◽  
Perry A Martos
Keyword(s):  
Nitric Acid ◽  
Organic Solvent ◽  
Aqueous Solutions ◽  
Chemical Etching ◽  
Room Temperature ◽  
Organic Content ◽  
Significant Loss ◽  
Type I ◽  
The Stability

Abstract The stability of aflatoxins B1, B2, G1, and G2 was studied in solutions containing different concentrations of water, acetonitrile, and/or methanol, and in autosampler vials treated with nitric acid or silanized. When stored at room temperature (20°C) for 24 h, aflatoxins G1 and G2 were stable only in solutions containing 100% organic solvent, whereas aflatoxins B1 and B2 were stable in solutions of methanol–water and acetonitrile–water at greater than 60 and 40% organic content, respectively. At 5°C, aflatoxins G1 and G2 showed a significant decrease in concentration only when kept in less than 20% aqueous organic solvent. Significant loss of aflatoxins was realized in standard, commercially available amber type I borosilicate autosampler vials, but chemical etching of the vials with nitric acid or with silanization prevented aflatoxin degradation. These results indicate that aflatoxins are unstable in aqueous solutions and that this instability can be counteracted by the presence of at least 20% organic solvent and keeping the solutions at 5°C or by the use of treated vials.

An electron spin resonance study of the hydrolytic products formed by titanium(III) trichloride in aqueous and mixed aqueous solutions and frozensolutions

1975 ◽  
Vol 28 (5) ◽  
pp. 999 ◽  
Author(s):  
DJ Cookson ◽  
TD Smith ◽  
JR Pilbrow
Keyword(s):  
Aqueous Solutions ◽  
Room Temperature ◽  
Major Product ◽  
Low Ph ◽  
Electron Spin Resonance Study ◽  
X Band ◽  
Symmetry Properties ◽  
Spin Resonance ◽  
Spin Resonance Study

X-band e.s.r. measurements of aqueous solutions containing titanium(III) trichloride at room temperature and 77 K provide evidence for the formation of aquated Ti(OH)2+ as the major product of hydrolysis at low pH, along with dimeric species Ti2(OH)24+ formed in small amounts. When certain organic solvents miscible with water are present a further hydrolytic product suggested to be Ti2(OH)5+ is found at low pH. Consideration of an interaction spin Hamiltonian which takes into account the symmetry properties of the paramagnetic ion pair systems makes possible the computer simulation of the experimental spectra due to the dimeric species. By this procedure the magnetic parameters associated with the titanium(III) dimers have been evaluated along with a determination of the titanium(III)-titanium(III) ion separations. This information has been used to suggest possible structures for the dimeric species.

Electron Spin Resonance Studies on Ti(H2O)63+ in Frozen Aqueous Solutions of Titanium(III) Chloride, Bromide, Iodide, and Sulfate

1975 ◽  
Vol 53 (11) ◽  
pp. 1630-1634 ◽  
Author(s):  
Pavle Ilija Premović ◽  
Paul Ronald West
Keyword(s):  
Electron Spin Resonance ◽  
Aqueous Solutions ◽  
Metal Ion ◽  
Room Temperature ◽  
Local Symmetry ◽  
Coordination Shell ◽  
Frozen Solution ◽  
Counter Ions ◽  
Spin Resonance ◽  
Maximum Signal

Strongly acidic aqueous solutions of titanium(III) chloride, bromide, iodide, or sulfate (0.02 M metal ion) provide no detectable e.s.r. signal at room temperature. In the frozen solution (77 K) an identical spectrum is observed from each sample with [Formula: see text] A maximum signal is observed at 6–8 M added anion, indicating not all titanium(III) species are e.s.r. active. Analysis indicates that the local symmetry of the Ti3+(3d1) ions providing the signal is D3. It is proposed that these ions are Ti(H2O)63+ species located in sites in the ice structure subject to a strong asymmetric electric field from nearby counter ions. Since the spectrum is independent of anion, the counter ions are unlikely to be in the first or second coordination shell of the Ti3+.

Room-Temperature Chemical Synthesis of C2

2019 ◽  
Author(s):  
Kazunori Miyamoto ◽  
Shodai Narita ◽  
Yui Masumoto ◽  
Takahiro Hashishin ◽  
Mutsumi Kimura ◽  
...  
Keyword(s):  
Chemical Synthesis ◽  
Ground State ◽  
Room Temperature ◽  
Chemical Species ◽  
Quadruple Bond ◽  
Photon Excitation ◽  
Physical Energy ◽  
Theoretical Predictions ◽  
Carbon Arc ◽  
Inherent Nature

Diatomic carbon (C<sub>2</sub>) is historically an elusive chemical species. It has long been believed that the generation of C<sub>2 </sub>requires extremely high “physical” energy, such as an electric carbon arc or multiple photon excitation, and so it has been the general consensus that the inherent nature of C<sub>2 </sub><i>in the ground state </i>is experimentally inaccessible. Here, we present the first “chemical” synthesis of C<sub>2 </sub>in a flask at <i>room temperature or below</i>, providing the first experimental evidence to support theoretical predictions that (1) C<sub>2 </sub>has a singlet biradical character with a quadruple bond, thus settling a long-standing controversy between experimental and theoretical chemists, and that (2) C<sub>2 </sub>serves as a molecular element in the formation of sp<sup>2</sup>-carbon allotropes such as graphite, carbon nanotubes and C<sub>60</sub>.

Room-temperature NaI/H2O compression icing: solute–solute interactions

2017 ◽  
Vol 19 (39) ◽  
pp. 26645-26650 ◽  
Author(s):  
Qingxin Zeng ◽  
Chuang Yao ◽  
Kai Wang ◽  
Chang Q. Sun ◽  
Bo Zou
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Bond Energy ◽  
Room Temperature ◽  
Solute Concentration ◽  
Solute Interaction ◽  
Solute Interactions

H–O bond energy governs the PCx for Na/H2O liquid–VI–VII phase transition. Solute concentration affects the path of phase transitions differently with the solute type. Solute–solute interaction lessens the PC2 sensitivity to compression. The PC1 goes along the liquid–VI boundary till the triple phase joint.

scholarly journals Crystal Growth of Cephalothin Sodium in Frozen Solution. III. Effect of Organic Solvent on Growth Rate

1985 ◽  
Vol 105 (3) ◽  
pp. 289-295 ◽  
Author(s):  
MASAYOSHI INOUE ◽  
HIROYOSHI TANAKA ◽  
KAZUHIRO SHIMA ◽  
KUNIHEI INAZU
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Organic Solvent ◽  
Frozen Solution
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