An infrared study of interactions in the system sodium tert-butoxide-tetrahydrofuran

1989 ◽  
Vol 54 (2) ◽  
pp. 308-315
Author(s):  
Libor Matějka ◽  
Lubomír Lochmann ◽  
Pavel Schmidt
Keyword(s):  
Stability Constant ◽  
Infrared Spectra ◽  
Adduct Formation ◽  
Large Excess ◽  
Infrared Study ◽  
Hydrocarbon Solvents ◽  
The Stability ◽  
System Sodium

The adduct of sodium tert-butoxide (t-BuONa) with tetrahydrofuran (THF) was studied by measuring changes of infrared spectra in the range 900-1100 cm-1. Alkoxide autoassociation and solvation of this associate by tetrahydrofuran play a role in adduct formation. In hydrocarbon solvents in the presence of minor amounts of THF, higher t-BuONa associates are dissociated, the preffered form being a tetramer solvated by three THF molecules. At large excess of THF, the tetramer is solvated by four THF molecules. The stability constant of the adduct, referred to one Na-O bond, is 5.01.

The coordination of β-amino ketoximes with divalent iron, cobalt, nickel and zinc

1978 ◽  
Vol 31 (11) ◽  
pp. 2409 ◽  
Author(s):  
HKJ Powell ◽  
JM Russell
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Stability Constant ◽  
Methyl Ether ◽  
Infrared Spectra ◽  
Iron Cobalt ◽  
Divalent Iron ◽  
Cobalt Nickel ◽  
Stability Order ◽  
The Stability

The iron(II), nickel(II) and zinc(II) complexes of the diamine dioxime ligand 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dioxime (H2dddo) and the cobalt(II), nickel(II) and zinc(II) complexes of its O-methyl ether (Hddmo) have been studied potentiometrically at 25°C, I 0.10M NaCl. Stability constant data are compared with those obtained for the copper(II) and cobalt(II) complexes of H2dddo and the copper(II) complexes of Hddmo. H2dddo coordinates in the oxime-oximato form [M(Hdddo)]+ with iron(II), cobalt(II), nickel(II) and zinc(II) Hddmo forms complexes with the ligand coordinated in the oxime form [M(Hddmo)]2+ and the oximato form [M(ddmo)]+. The complexes [Zn(Hddmo)2]2+, [Zn(Hddmo)(ddmo)]+ and [Co(ddmo)(OH)] were also characterized in aqueous solution. The stability order FeII < CoII < NiII < CuII > ZnII was observed for the formation of 1 : 1 complexes with the ligands Hdddo- (log K = 8.8, 11.7, 15.2, 23.3, 12.0 for Fe to Zn respectively) and Hddmo (5.7, 6.6, 12.1, 5.3 for Co to Zn). The infrared spectra of the complexes [Ni(Hdddo)] ClO4,H2O and [Zn(Hdddo)] ClO4 are discussed in terms of oxime-oximato hydrogen bonding.

Synthesis and solvatochromic studies of 2- amino-3-phenolazo1-(4-sulfophenyl)-3-methyi-5-pyrozolone and use it for the determination of trace amount of Nickel (II) in blood samples

2016 ◽  
Vol 5 (10) ◽  
pp. 4920
Author(s):  
Amar M. Ali ◽  
Hussain. J. Mohammed*
Keyword(s):  
Stability Constant ◽  
Trace Amount ◽  
Benzenesulfonic Acid ◽  
Determination Method ◽  
Blood Samples ◽  
Determination Of Nickel ◽  
Normal Human ◽  
The Stability ◽  
Normal Human Blood

A new, simple, sensitive and rapid spectrophotometric method is proposed for the determination of trace amount of Nickel (II). The method is based on the formation of a 1:2 complex with 4-(4-((2-hydroxy-6-nitrophenyl) diazenyl) -3-methyl-5-oxo-2, 5-dihydro-1H-pyrazol-1-yl) benzenesulfonic acid (2-ANASP) as a new reagent is developed. The complex has a maximum absorption at 516 nm and εmax of 1. 84 X 105 L. mol-1. cm-1. A linear correlation (0. 25 – 4. 0μg. ml-1) was found between absorbance at λmax and concentration. The accuracy and reproducibility of the determination method for various known amounts of Nickel (II) were tested. The results obtained are both precise (RSD was 1. 2 %) and accurate (relative error was 0. 787 %). The effect of diverse ions on the determination of Nickel (II) to investigate the selectivity of the method were also studied. The stability constant of the product was 0. 399 X 106 L. mol-1. The proposed method was successfully applied to the analysis of diabetes blood and normal human blood. 

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

Determination of the Stability Constant of the Calcium Dioxalate Complex

Urolithiasis ◽  
1981 ◽  
pp. 447-451
Author(s):  
John R. Burns ◽  
Birdwell Finlayson ◽  
Arthur Smith
Keyword(s):  
Stability Constant ◽  
The Stability

SODIUM CHELATES OF ETHYLENEDIAMINETETRAACETIC ACID

1963 ◽  
Vol 41 (1) ◽  
pp. 18-20 ◽  
Author(s):  
Vladimir Palaty
Keyword(s):  
Stability Constant ◽  
Stability Constants ◽  
Ethylenediaminetetraacetic Acid ◽  
Glass Electrode ◽  
Neutral Solution ◽  
Experimental Conditions ◽  
The Stability ◽  
Sensitive Method

The stability constant of the sodium chelate of EDTA was determined by means of a sodium-sensitive glass electrode. It appears that a hydrogen chelate of the formula NaHY2− is formed in the neutral solution of EDTA, but is very unstable. The stability constants, pKNaY = −2.61 and pKNaHY = 0.03, are comparable to the value obtained by Schwarzenbach and Ackermann under different experimental conditions by a less sensitive method.

scholarly journals New Spectrophotometric Method for Determination of Cadmium

2009 ◽  
Vol 6 (s1) ◽  
pp. S496-S500
Author(s):  
K. S. Parikh ◽  
R. M. Patel ◽  
K. N. Patel
Keyword(s):  
Stability Constant ◽  
Spectrophotometric Method ◽  
Basic Medium ◽  
Buffer Solution ◽  
Solution Ph ◽  
Yellow Colour ◽  
Maximum Absorbance ◽  
The Stability

The reagent 2-hydroxy-4-n-butoxy-5-bromopropiophenone thiosemicarbazone (HBBrPT) has been used for the determination of Cd(II) by using spectrophotometric method. The reagent HBBrPT gave an intense yellow colour with Cd(II) solution in basic medium. The maximum absorbance was observed at 440 nm, in basic buffer solution (pH 10.00). The molor absorptivity and Sandell’s sensitivity of Cd(II)-HBBrPT complex were 4035 mol-1cm-1and 0.02765 μg cm-2respectively. The stability constant of 1:2 Cd(II)-HBBrPT complex was 8.46×106. The effect of various iron was also studied.

scholarly journals Synthesis of Some 3d Metal Complexes of Quinine and their Toxicological Studies

1970 ◽  
Vol 25 ◽  
pp. 19-28 ◽  
Author(s):  
Adedibu C. Tella ◽  
Joshua A. Obaleya
Keyword(s):  
Stability Constant ◽  
Metal Complexes ◽  
Chemical Society ◽  
Cinchona Alkaloids ◽  
Albino Rats ◽  
Spectroscopic Techniques ◽  
Tetrahedral Geometry ◽  
Toxicological Studies ◽  
3D Metal Complexes ◽  
The Stability

Four metal complexes of antimalarials cinchona alkaloids; [Co(Quin)Cl3]-1,[Fe(Quin)Cl2H2O]SO3H2O-2, [Cu(Quin)ClSO4]∞-3 and [Cd(Quin)ClSO4]∞-4 have beensynthesized and characterized by elemental analysis, conductivity, magnetic moment, IR,UV-Vis and mass spectroscopic techniques. The tetrahedral geometry is assigned for all thefour complexes and the quinine ligand is protonated at quinuclidine N atom with thecoordination of the metal at quinoline N atom for all the complexes. Complexes 1 and 2have zwitterionic structures while complexes 3 and 4 are polymeric in nature with zig-zagextended chains (MCl- O -SO2- O -MCl- O –SO2---).Stability constant of the complexes were evaluated for the metal salts. The value of thestability constant (β) was found to be log 10.48, 9.92, 7.98 and 7.81 for Cu(II), Fe(III),Co(II) and Cd(II), respectively and the order of β was found to beCu(II)>Fe(III)>Co(II)>Cd(II). The stability constant data revealed that concomitantlyadministration of quinine with preparation containing these metals may reduce theirefficacy. Toxicological study was carried out by investigating the effect of administration ofthe complexes on alkaline phosphatase activity of kidney, liver and serum of Albino rats. Allthe examined four metal complexes were found to be non-toxic.Keywords: Quinine, stability constant, FTIR, MS, phosphates activity.DOI:  10.3126/jncs.v25i0.3280Journal of Nepal Chemical Society Volume 25, 2010 pp 19-28

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