ChemInform Abstract: KINETICS OF THE ACID DISSOCIATION OF THE COPPER(II) AND NICKEL(II) COMPLEXES OF 5,7-DIOXO-1,4,8,11-TETRAAZACYCLOTETRADECANE

1985 ◽  
Vol 16 (1) ◽  
Author(s):  
R. W. HAY ◽  
M. P. PUJARI ◽  
F. MCLAREN
Keyword(s):  
Acid Dissociation ◽  
Kinetics Of

The comparative chemistry of ammine and methylamine complexes of rhodium(III) and cobalt(III)

1977 ◽  
Vol 55 (17) ◽  
pp. 3166-3171 ◽  
Author(s):  
Thomas Wilson Swaddle
Keyword(s):  
Ionic Strength ◽  
Spectral Data ◽  
Electron Donor ◽  
Dissociation Constants ◽  
Base Hydrolysis ◽  
Acid Dissociation ◽  
Rate Coefficients ◽  
Acid Dissociation Constants ◽  
First Order ◽  
Kinetics Of

For the aquation of (CH3NH2)5RhCl2+, the first order rate coefficients are represented by ΔHaq* = 101.9 kJ mol−1 and ΔSaq* = −50.2 JK−1 mol−1 in 0.1 M HClO4, while for base hydrolysis the rate is first order in [(CH3NH2)5RhCl2+] and [OH−] at ionic strength 0.10 M and the rate coefficients (in M−1 s−1) are represented by ΔHOH*> = 108.6 kJ mol−1 and ΔSOH* = 74.1 J K−1 mol−1. Acid dissociation constants are reported for (RNH2)5MOH23+ (R = H or CH3; M = Rh or Co), and these, combined with spectral data, show CH3NH2 to be a poorer electron donor than NH3 in complexes of this type, contrary to expectations. The comparative kinetics of reactions of (RNH2)5MCl2+ support the assignment of an Ia mechanism to aquation when M = Rh or Cr, Id to aquation when M = Co, and Dcb for base hydrolysis in all these cases.

Stopped-flow kinetic analysis of long-chain fatty acid dissociation from bovine serum albumin

2002 ◽  
Vol 363 (3) ◽  
pp. 809-815 ◽  
Author(s):  
Erland J.F. DEMANT ◽  
Gary V. RICHIERI ◽  
Alan M. KLEINFELD
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Time Course ◽  
Acid Dissociation ◽  
Fatty Acid Transport ◽  
Acid Transport ◽  
Fatty Acid Binding ◽  
Kinetics Of ◽  
Initial Fatty Acid ◽  
Long Chain

The kinetics of the interaction of long-chain fatty acids (referred to as fatty acids) with albumin is critical to understanding the role of albumin in fatty acid transport. In this study we have determined the kinetics of fatty acid dissociation from BSA and the BSA-related fatty acid probe BSA-HCA (BSA labelled with 7-hydroxycoumarin-4-acetic acid) by stopped-flow methods. Fatty acid—albumin complexes of a range of natural fatty acid types and albumin molecules (donors) were mixed with three fatty acid-binding acceptor proteins. Dissociation of fatty acids from the donor was monitored by either the time course of donor fluorescence/absorbance or the time course of acceptor fluorescence. The results of these measurements indicate that fatty acid dissociation from BSA as well as BSA-HCA is well described by a single exponential function over the entire range of fatty acid/albumin molar ratios used in these measurements, from 0.5:1 to 6:1. The observed rate constants (kobs) for the dissociation of each fatty acid type reveal little or no dependence on the initial fatty acid/albumin ratio. However, dissociation rates were dependent upon the type of fatty acid. In the case of native BSA with an initial fatty acid/BSA molar ratio of 3:1, the order of kobs values was stearic acid (1.5s−1)<oleic acid<palmitic acid≅linoleic acid<arachidonic acid (8s−1) at 37°C. The corresponding values for BSA-HCA were about half the values for BSA. The results of this study show that the rate of fatty acid dissociation from native BSA is more than 10-fold faster than reported previously and that the off-rate constants for the five primary fatty acid-binding sites differ by less than a factor of 2. We conclude that for reported rates of fatty acid transport across cell membranes, dissociation of fatty acids from the fatty acid—BSA complexes used in the transport studies should not be rate-limiting.

Kinetic and equilibrium studies of the acid dissociation of the cobalt(II) complexes of N,N'-dialkyl- 1,10-phenanthroline-2,9-dimathanamine ligands

1999 ◽  
Vol 77 (9) ◽  
pp. 1471-1475 ◽  
Author(s):  
Hongwei Sun ◽  
Zhifen Zhou ◽  
Huakuan Lin ◽  
Guanghua Zhao ◽  
Shourong Zhu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Key Words ◽  
Dissociation Rate ◽  
Acid Dissociation ◽  
Stopped Flow ◽  
Isokinetic Temperature ◽  
Dissociation Kinetics ◽  
Equilibrium Studies ◽  
Complexation Property ◽  
Kinetics Of

The complexation property and the acid dissociation kinetics of four N,N'-dialkyl-1,10-phenanthroline-2,9-dimathanamine complexes with cobalt(II) were studied using a pH meter and a stopped-flow spectrophotometer. In 6.6 × 10-3~0.5 mol dm-3 HCl (I = 0.5 mol dm-3 HCl + NaCl), the dissociation rate follows the law kobs = kK2[H+]/(1 + K2[H+]). The acid dissociation can be rationalized in terms of a four-step kinetic process involving two rapid pre-equilibrium protonations and rate-determining cleavage of the Co(II)-N(phenanthroline) bond. The temperature dependence of the rate was determined, and the appropriate thermodynamic parameters were obtained. The linear relationship between ΔH not equal and ΔS not equal suggests that an isokinetic temperature, Tiso of 282 ± 2 K exists. Key words: N,N'-dialkyl-1,10-phenanthroline-2,9-dimathanamine, complexation property, acid dissociation kinetics, mechanism, cobalt(II) complex.

Studies on Horseradish Peroxidase. VII. A Kinetic Study of the Oxidation of Iodide by Horseradish Peroxidase Compound II

1971 ◽  
Vol 49 (18) ◽  
pp. 3059-3063 ◽  
Author(s):  
R. Roman ◽  
H. B. Dunford ◽  
M. Evett
Keyword(s):  
Ionic Strength ◽  
Horseradish Peroxidase ◽  
Kinetic Study ◽  
Rate Constant ◽  
Ph Dependence ◽  
Order Rate Constant ◽  
Acid Dissociation ◽  
Ph Range ◽  
Compound Ii ◽  
Kinetics Of

The kinetics of the oxidation of iodide ion by horseradish peroxidase compound II have been studied as a function of pH at 25° and ionic strength of 0.11. The logarithm of the second-order rate constant decreases linearly from 2.3 × 105 to 0.1 M−1 s−1 with increasing pH over the pH range 2.7 to 9.0. The pH dependence of the reaction is explained in terms of an acid dissociation outside the pH range of the study.

Acid dissociation constant and decay kinetics of the perhydroxyl radical

1970 ◽  
Vol 74 (17) ◽  
pp. 3209-3213 ◽  
Author(s):  
David Behar ◽  
Gideon Czapski ◽  
Joseph Rabani ◽  
Leon M. Dorfman ◽  
Harold A. Schwarz
Keyword(s):  
Dissociation Constant ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Decay Kinetics ◽  
Perhydroxyl Radical ◽  
Kinetics Of

Acid dissociation kinetics of the deprotonated nickel(II)-tetraglycinamide complex

1980 ◽  
Vol 19 (2) ◽  
pp. 497-500 ◽  
Author(s):  
John M. T. Raycheba ◽  
Dale W. Margerum
Keyword(s):  
Acid Dissociation ◽  
Dissociation Kinetics ◽  
Kinetics Of

Kinetics of acid dissociation-ion recombination of aqueous methyl orange

1972 ◽  
Vol 76 (26) ◽  
pp. 4023-4025 ◽  
Author(s):  
Richard G. Sandberg ◽  
Gary H. Henderson ◽  
Robert D. White ◽  
Edward M. Eyring
Keyword(s):  
Methyl Orange ◽  
Acid Dissociation ◽  
Ion Recombination ◽  
Kinetics Of
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