Electronic and Raman spectroscopic studies of copper adrenalin complexes and copper induced compounds

1976 ◽  
Vol 54 (24) ◽  
pp. 3815-3823 ◽  
Author(s):  
Mohammed S. Rahaman ◽  
Stephen M. Korenkiewicz
Keyword(s):  
Free Radical ◽  
Hydrochloric Acid ◽  
Raman Spectra ◽  
Spectroscopic Studies ◽  
Low Ph ◽  
Basic Solution ◽  
High Ph ◽  
Raman Spectroscopic ◽  
Ph Values

Electronic and Raman spectra of adrenalin–copper(II) complexes and copper catalyzed compounds have been studied. Adrenalin reacts with copper(II) ion at pH 9.2 and higher to produce a very short lived violet free radical, a brown adrenochrome, a yellow conjugated salt, indolyl-indoquinone, and melanin. Results indicate that copper does not form complexes with adrenalin in basic solution. Between pH 6.5 and 8.5 adrenalin transforms into adrenochrome in presence of copper. The adrenochrome in 1.5 N hydrochloric acid produces the conjugate salt that is produced in the solution of high pH. At low pH values, between pH 4.0 to 5.5, adrenalin forms a brown complex with copper(II). Copper is entirely chelated to the phenolic groups of the amines. The complex in 1.5 N hydrochloric acid produces a black polymeric pigment.

Raman Spectroscopic Studies of the Vulcanization of Rubbers. III. Studies of Vulcanization Systems Based on 2-Mercaptobenzothiazole

1972 ◽  
Vol 45 (1) ◽  
pp. 173-181 ◽  
Author(s):  
M. M. Coleman ◽  
J. R. Shelton ◽  
J. L. Koenig
Keyword(s):  
Raman Spectra ◽  
Raman Line ◽  
Lauric Acid ◽  
Spectroscopic Studies ◽  
Type I ◽  
Raman Spectroscopic ◽  
Major Significance ◽  
Sulfur Vulcanization ◽  
Cyclic Sulfide

Abstract The shoulder observed at approximately 440 cm−1 in Raman spectra of CB vulcanizates prepared from MBT based vulcanizing systems has been shown to consist of two components. There are Raman lines contributing at 440 cm−1 and 424 cm−1. The former is due to ZnO present as an extra-network material while the latter appears to be associated with polysulfidic structures. The Raman line at 505 cm−1 seen in extracted vulcanizates prepared from CB-MBT-Sulfur-ZnO-Lauric acid recipes does not appear to be solely due to disulfidic structures. The major contribution appears to be associated with an unsaturated cyclic sulfide and is most probably due to a structure of the type (I). If the assignment to cyclic sulfidic structures such as (I) is confirmed, it will have major significance with regard to the mechanism of accelerated sulfur vulcanization.

scholarly journals pH-jump studies at subzero temperatures on an intermediate in the reaction of xanthine oxidase with xanthine

1978 ◽  
Vol 175 (3) ◽  
pp. 879-885 ◽  
Author(s):  
A D Tsopanakis ◽  
S J Tanner ◽  
R C Bray
Keyword(s):  
Nitrate Reductase ◽  
Xanthine Oxidase ◽  
Low Ph ◽  
High Ph ◽  
Ph Values ◽  
Exchangeable Proton ◽  
Subzero Temperatures ◽  
Ph Jump ◽  
Unique Nature ◽  
Prototropic Equilibrium

Xanthine oxidase is stable and active in aqueous dimethyl sulphoxide solutions of up to at least 57% (w/w). Simple techniques are described for mixing the enzyme in this solvent at–82 degrees C, with its substrate, xanthine. When working at high pH values under such conditions, no reaction occurred, as judged by the absence of e.p.r. signals. On warming to–60 degrees C, for 10 min, however, the Very Rapid molybdenum(V) e.p.r. signal was obtained. This signal did not change on decreasing the pH, while maintaining the sample in liquid nitrate reductase, caused its molybdenum(V) e.p.r. signal to change from the high-pH to the low-pH form. These findings are not compatible with the conclusions of Edmondson, Ballou, Van Heuvelen, Palmer & Massey [J. Biol. Chem. (1973) 248, 6135-6144], that the Very Rapid signal is in prototropic equilibrium with the Rapid signal, and should be important in understanding the mechanism of action of the enzyme. They emphasize the unique nature of the intermediate represented by the Very Rapid e.p.r. signal. The possible value of the pK for loss of an exchangeable proton from the Rapid signal is discussed.

Hydrothermal crystallization kinetics of m-ZrO2 and t-ZrO2

1990 ◽  
Vol 5 (11) ◽  
pp. 2698-2705 ◽  
Author(s):  
Raymond P. Denkewicz ◽  
Kevor S. TenHuisen ◽  
James H. Adair
Keyword(s):  
Crystallization Kinetics ◽  
Low Ph ◽  
Formation Mechanisms ◽  
Gel Structure ◽  
Hydrothermal Conditions ◽  
High Ph ◽  
Ph Values ◽  
Ph Conditions ◽  
Apparent Activation Energies ◽  
Kinetics Of

The isothermal nucleation and crystallization kinetics of hydrothermally prepared monoclinic and tetragonal ZrO2 have been determined at various pH conditions. It is shown that monoclinic ZrO2 precipitates at low pH whereas at high pH tetragonal ZrO2 crystallizes from an amorphous zirconium (hydrous) oxide, Zr(OH)xOy, precursor. At intermediate pH conditions mixtures of the polymorphs are formed suggestive of kinetically competing particle formation mechanisms. The data are explained by the proposed existence of three controlling regimes for the formation of crystalline ZrO2: dissolution/precipitation at low pH, a solubility controlled regime at intermediate pH values, and a gel structure controlled regime at high pH. Apparent activation energies for the nucleation and crystallization of monoclinic and tetragonal ZrO2 formed under hydrothermal conditions are presented.

Infrared and Raman Spectroscopic Studies of Solid Alkali Metal Nitrites

1971 ◽  
Vol 49 (8) ◽  
pp. 1289-1295 ◽  
Author(s):  
M. H. Brooker ◽  
D. E. Irish
Keyword(s):  
Alkali Metal ◽  
Raman Spectra ◽  
Spectroscopic Studies ◽  
Infrared And Raman Spectra ◽  
Nitrite Ion ◽  
Nitrate Ion ◽  
Raman Spectroscopic ◽  
Linkage Isomerism ◽  
Vibrational Bands ◽  
Cation Size

Infrared and Raman spectra of solid LiNO2•H2O, LiNO2, NaNO2, KNO2, and CsNO2 are presented and discussed. Pronounced changes in the spectra of LiNO2•H2O during dehydration to anhydrous LiNO2 are interpreted as evidence for an ordered distribution of NO2− ions over two non-equivalent sites (akin to linkage isomerism) in anhydrous LiNO2. The frequencies of the internal modes of the nitrite ion shift to lower values with increasing cation size. Vibrational bands due to nitrate ion present as an impurity are assigned.

scholarly journals pH Tolerance in Freshwater Bacterioplankton: Trait Variation of the Community as Measured by Leucine Incorporation

2015 ◽  
Vol 81 (21) ◽  
pp. 7411-7419 ◽  
Author(s):  
Erland Bååth ◽  
Emma Kritzberg
Keyword(s):  
Bacterial Growth ◽  
Low Ph ◽  
Tolerance Index ◽  
Response Curves ◽  
Trait Variation ◽  
High Ph ◽  
Ph Values ◽  
Ph Tolerance ◽  
Community Tolerance

ABSTRACTpH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, coveringin situpH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) instantaneously after pH adjustment. The resulting unimodal response curves, reflecting community tolerance to pH, were well modeled with a double logistic equation (meanR2= 0.97). The optimal pH for growth (pHopt) among the bacterial communities was closely correlated within situpH, with a slope (0.89 ± 0.099) close to unity. The pH interval, in which growth was ≥90% of that at pHopt, was 1.1 to 3 pH units wide (mean 2.0 pH units). Tolerance response curves of communities originating from circum-neutral pH were symmetrical, whereas in high-pH (8.9) and especially in low-pH (<5.5) waters, asymmetric tolerance curves were found. In low-pH waters, decreasing pH was more detrimental for bacterial growth than increasing pH, with a tendency for the opposite for high-pH waters. A pH tolerance index, using the ratio of growth at only two pH values (pH 4 and 8), was closely related to pHopt(R2= 0.83), allowing for easy determination of pH tolerance during rapid changes in pH.

Effects of pH on Hg0 Re-Emission in WFGD

2014 ◽  
Vol 960-961 ◽  
pp. 462-468 ◽  
Author(s):  
Yong Qiu ◽  
Hui Wu ◽  
Guang Qian Luo ◽  
Hong Yao
Keyword(s):  
Flue Gas ◽  
Laboratory Experiments ◽  
Low Ph ◽  
Time Span ◽  
Flue Gas Desulfurization ◽  
Solution Theory ◽  
High Ph ◽  
Ph Values ◽  
Effects Of Ph ◽  
Conventional Solution

Gaseous oxidized mercury (Hg2+) in the flue gas is soluble in water and can be captured effectively by Wet flue gas desulfurization (WFGD) system. But in some extent Hg0re-emission happens due to the reduction of absorbed Hg2+, and the pH of slurry is an important factor affecting Hg0re-emission. In this study, the theoretical formulas of slurry pH were derived through the conventional solution theory and then were used to evaluate the factors determining the pH of slurry. A series of laboratory experiments were carried out under N2,CO2and O2/N2atmosphere to measure the Hg0re-emission tendency at different pH values. The results show that the higher the pH, the less Hg2+reduced by S(IV), resulting in the decrease of Hg0re-emission. Under N2atmosphere, the Hg0re-emission was mild at pH>4 while it was dramatic at pH<4. Under O2/N2atmosphere, the addition of O2extended the time span of Hg0re-emission at low pH and increased Hg0re-emission unexpectedly in the latter part of the experiments at high pH. CO2atmosphere almost did not affect Hg0re-emission because of its little effect on the slurry pH.

scholarly journals Structural Changes of Co Caused a Change of the Solution pH During Chemical Deposition

2020 ◽  
pp. 451-458
Author(s):  
Sergey A. Podorozhnyak ◽  
Anatoly V. Chzhan ◽  
Vadim K. Maltsev ◽  
Ivan N. Krayuhin ◽  
Gennady S. Patrin ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Crystal Lattice ◽  
Phase Transformations ◽  
Structural Changes ◽  
Chemical Deposition ◽  
Low Ph ◽  
Nanocrystalline State ◽  
Solution Ph ◽  
High Ph ◽  
Ph Values

The phase transformations of the Co lattice are discussed, which determine the anomalous changes in the magnetic properties of chemically deposited Co-P films obtained at various pH values. The coercivity of the Hc films obtained at low pH values exceeds 1 kOe and decreases to several units Oe in the films obtained at high pH values. It is shown that the observed changes in the magnetic properties of Co-P films are caused by the transition of the cobalt crystal lattice to the nanocrystalline state

THE EFFECT OF NITROGEN AND PHOSPHORUS NUTRITION ON pH OF TOMATO

1966 ◽  
Vol 46 (6) ◽  
pp. 681-684 ◽  
Author(s):  
J. S. Matthews ◽  
L. G. Denby
Keyword(s):  
Low Ph ◽  
The Other ◽  
Phosphorus Nutrition ◽  
Nitrogen And Phosphorus ◽  
Tomato Fruits ◽  
High Ph ◽  
Ph Values ◽  
Low Levels ◽  
Nutrient Solutions

Tomato fruits, grown under glass in inert media, and supplied with nutrient solutions containing high and low levels of N and P, varied in pH from 4.21 to 4.61. Fruits from plants receiving low levels of both nutrients consistently had low pH values. Those from plants fed high levels of P or N had high pH whenever the level of the other element was not limiting.

Raman spectroscopic studies on structure I and structure IItrimethylene oxide hydrate

2005 ◽  
Vol 83 (9) ◽  
pp. 941-949 ◽  
Author(s):  
S Subramaniam ◽  
M J Lance ◽  
C J Rawn ◽  
B C Chakoumakos ◽  
A J Rondinone
Keyword(s):  
Raman Spectra ◽  
Variable Temperature ◽  
Spectroscopic Studies ◽  
Host Lattice ◽  
Vibrational Modes ◽  
Cage Structure ◽  
Raman Spectroscopic ◽  
Oxide Hydrate ◽  
Wave Numbers ◽  
Trimethylene Oxide

Raman spectra were collected from structure I (sI) and structure II (sII) trimethylene oxide (TMO) hydrates at various temperatures and used to assign the vibrational modes, investigate the ordering of TMO molecules inside the cage structure, and to determine possible interactions between the guest and the host lattice. Only Raman spectra from sI hydrate could be analyzed since the low concentration of TMO prevented sII peaks from being resolved. Comparison of the Raman spectra of liquid, solid, and enclathrated TMO (sI) showed Raman shifts to higher wave numbers for the enclathrated TMO; mainly among the ring modes. The ring and (or) skeletal modes around 930 cm–1 and the asymmetric CH2 stretching mode around 2970 cm–1, showed shifts greater than 10 cm–1. These observed changes are interpreted on the basis of the "loose-cage – tight-cage" model, which interprets the shift as arising from strain induced by the hydrate cage on the guest TMO molecules in the 62 cages. In addition, variable temperature Raman studies, in the temperatures ranging from 103 to 203 K, showed no evidence of ordering and (or) reorientation of host molecules. PACS No.: 78.30.-j

Comparative Study of p-nitrophenyl picolinate Hydrolysis Catalyzed by Bis(O,O’-di(2-phenylalkyl)dithiophosphate) nickel(II)

2012 ◽  
Vol 560-561 ◽  
pp. 305-308 ◽  
Author(s):  
Bing Ying Jiang ◽  
Fa Mei Feng ◽  
Min Wang ◽  
Ci Li ◽  
Jia Qing Xie
Keyword(s):  
Comparative Study ◽  
Metal Complexes ◽  
Low Ph ◽  
Nucleophilic Attack ◽  
High Ph ◽  
Ph Values ◽  
Catalytic Function ◽  
Hydrolysis Of ◽  
Pnpp Hydrolysis ◽  
Synergism Effect

The hydrolysis of p-nitrophenyl picolinate (PNPP) catalyzed by two nickel (II) complexes (bis(O,O’-di(2-phenylmethyl) dithiophosphate) nickel(II) (NiR1) and bis(O,O’-di(2-phenylethyl) dithiophosphate) nickel(II) (NiR2)) was investigated kinetically in this work. The results indicate that both metal complexes accelerate the hydrolysis of PNPP dramatically and the NiR1 exhibits higher catalytic function on PNPP hydrolysis in the buffered solution with relatively low pH values, while NiR2 shows slightly more efficacy on hydrolysis of PNPP in relatively high pH buffered solutions. This variance is ascribed to the synergism effect of space hindrance of the complexes and the nucleophilic attack of metal-hydroxy species generated by the complexes.

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