RATE CONSTANTS, ACTIVATION PARAMETERS, AND SALT EFFECTS FOR THE ACID DISSOCIATION OF (CH3)3NH+IN AQUEOUS SOLUTION, AND FOR ITS REACTION WITH (CH3)3N

1963 ◽  
Vol 67 (10) ◽  
pp. 2208-2211 ◽  
Author(s):  
Ernest Grunwald
Keyword(s):  
Aqueous Solution ◽  
Rate Constants ◽  
Activation Parameters ◽  
Acid Dissociation ◽  
Salt Effects

Octahedral cobalt(III) complexes of the chloropentanimine type. XXX. The thallium(III)-induced aquation of some cis-Halogeno(amine)bis(ethylenediamine)cobalt(III) cations in aqueous solution

1973 ◽  
Vol 26 (6) ◽  
pp. 1235 ◽  
Author(s):  
SC Chan ◽  
SF Chan
Keyword(s):  
Aqueous Solution ◽  
Rate Constants ◽  
Activation Parameters ◽  
Second Order ◽  
Alternative Possibility ◽  
Order Rate ◽  
Leaving Group ◽  
Activated Complex

The second-order rate constants for the thallium(III)-induced aquation of cis-[Co(en)2(RNH2)Cl]2+ cations, where R is H, Me, Et, Prn, and Pri, have been measured in aqueous solution over a range of temperatures, and the activation parameters calculated. The kinetic results are discussed in terms of a rapid pre-equilibrium formation of an activated complex Co-Cl-Tl, followed by a simple rate-determining aquation in which TlCl2+ acts as the leaving group, although the alternative possibility of a rate-determining attack by Tl3+ cannot be excluded. In the case of R = H, the investigations have been extended to the corresponding bromo cation which reacts some 50 times faster than its chloro analogue.

Ligand substitution reactions of pentacyanoferrate(II) complexes with N-heterocyclic cations in aqueous solution

1989 ◽  
Vol 67 (11) ◽  
pp. 1774-1779 ◽  
Author(s):  
Donal Hugh Macartney ◽  
Lauren Jean Warrack
Keyword(s):  
Aqueous Solution ◽  
Rate Constants ◽  
Dissociation Constants ◽  
Formation Rate ◽  
Spectroscopic Studies ◽  
Ligand Substitution ◽  
Acid Dissociation ◽  
Specific Rate ◽  
Dissociative Mechanism ◽  
Heterocyclic Cations

Kinetic and spectroscopic studies have been carried out in aqueous solution on the formation (from Fe(CN)5OH23−) and dissociation of pentacyanoferrate(II) complexes containing 1-(4-pyridyl)pyridinium and the neutral, protonated, and N-methylated forms of 4,4′-bipyridine (BPY), 1,2-bis(4-pyridyl)ethane (BPA), and trans-1,2-bis(4-pyridyl)ethylene (BPE). The pH dependences of the formation kinetics have been analyzed in terms of the specific rate and acid dissociation constants for these ligands. The rate constants (25.0 °C, I = 0.10 M) for the formation of the dinuclear complexes (NC)5FeLFe(CN)56− have been determined for BPY (50 M−1 s−1), BPA (66 M−1 s−1), BPE (95 M−1 s−1), and pyrazine (10 M−1 s−1), and are compared with the respective rate constants for the formation of (NC)5FeLCo(NH3)5. The relationships between the formation rate constants and the size of the ligand, the number of donor sites, and the magnitude and position of charges on the ligand are discussed in terms of an ion-pair dissociative mechanism. Keywords: pentacyanoferrate(II) complexes, N-heterocycles, ligand substitution, kinetics.

Kinetic studies of ring closures in platinum(II) chelates. Rate constants and activation parameters for chelation of platinum(II) by bis(2-aminoethyl) sulfide in aqueous solution

1979 ◽  
Vol 18 (6) ◽  
pp. 1451-1454 ◽  
Author(s):  
G. Albertin ◽  
E. Bordignon ◽  
A. A. Orio ◽  
B. Pavoni ◽  
Harry B. Gray
Keyword(s):  
Aqueous Solution ◽  
Rate Constants ◽  
Activation Parameters ◽  
Kinetic Studies

scholarly journals Studies on Cyclic Anhydrides. I. Rate Constants and Activation Parameters for the Solvolysis of Alkylsubstituted Cyclic Anhydrides in Aqueous Solution by the pH-stat Method.

1964 ◽  
Vol 18 ◽  
pp. 534-542 ◽  
Author(s):  
Lennart Eberson ◽  
Martin Nilsson ◽  
J. A. Elvidge ◽  
J. S. Burton ◽  
Roger Stevens
Keyword(s):  
Aqueous Solution ◽  
Rate Constants ◽  
Activation Parameters ◽  
Ph Stat ◽  
Cyclic Anhydrides ◽  
Stat Method

Dissociation kinetics of metal complexes in acid. Copper complexes of triazamacrocycles

1981 ◽  
Vol 34 (2) ◽  
pp. 291 ◽  
Author(s):  
PG Graham ◽  
DC Weatherburn
Keyword(s):  
Aqueous Solution ◽  
Copper Complexes ◽  
Activation Parameters ◽  
Macrocyclic Complex ◽  
Acid Dissociation ◽  
General Mechanism ◽  
Dissociation Kinetics ◽  
First Order ◽  
High Concentrations ◽  
Kinetics Of

The acid dissociation kinetics of the mono-copper complexes of 1,4,7-triazacyclononane, znn; 1,4,7-triazacyclodecane, zdn; 1,4,8-triazacycloundecane, zud; 1,5,9-triazacyclododecane, zdd; 2,2,4-trimethyl-1,5,9-triazacyclododecane, tmzdd; 1,5,9-triazacyclotridecane, ztd; and cyclohexane- r-1,c-3,c-5 triamine, ccha, were studied in aqueous solution over a range of acid concentrations (0.025-0.5 mol dm-3), I 1.0 (NaN03). A variety of kinetic behaviour is observed. Cu(znn)2+, Cu(zdn)2+ and Cu(zud)2+ display a first-order dependence upon [H+] with kH (298 K) 51 dm3 mol-1 s-1 (znn), 17 dm3 mol-1 s-1 (zdn), and 5.6 dm3 mol-1 s-1 (zud). Cu(zdd)2+, Cu(ztd)2+ and Cu(ccha)2+ show a dependence on [H+] at low acid concentrations but become acid-independent at high concentrations. The acid-independent rate constants are k1 (298 K) 2.2 s-1 (zdd), 15.4 s-1 (ztd) and k1 (283 K) 75 s-1 (ccha). Cu(tmzdd)2+ shows a rate law of the form rate = k+kH[H+] with k (298 K) 1.8×10 s-1 and kH (298 K) 2.0×10-3 dm3 mol-1 s-1. Activation parameters have been determined in all cases except Cu(ccha)2+ which was studied at 10�C. The results are compared with other macrocyclic complex systems, and a general mechanism for these reactions is discussed.

Instability of Solutions of Quaternary Ammonium Permanganates in Dichloromethane

1997 ◽  
Vol 62 (6) ◽  
pp. 849-854 ◽  
Author(s):  
Vladislav Holba ◽  
Renata Košická
Keyword(s):  
Ammonium Salt ◽  
Rate Constants ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salt ◽  
Activation Parameters ◽  
The Stability

The paper deals with instability of solutions of quaternary ammonium permanganates, QMnO4 (Q = tetraethyl-, tetra-1-propyl-, tetra-1-butyl-, tetra-1-pentyl-, tetra-1-octyl-, and cetyltrimethylammonium), in dichloromethane and presents the rate constants and activation parameters of the reduction of permanganate. Attention was paid to the properties of colloidal Mn(IV) intermediate. The stability of the solutions depends markedly on the quaternary ammonium salt used.

Kinetics and mechanism of the reaction of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione

1990 ◽  
Vol 55 (8) ◽  
pp. 1984-1990 ◽  
Author(s):  
José M. Hernando ◽  
Olimpio Montero ◽  
Carlos Blanco
Keyword(s):  
Aqueous Solution ◽  
Metal Ion ◽  
Activation Parameters ◽  
Enol Form ◽  
Kinetics And Mechanism ◽  
Kinetic Constants ◽  
Steric Factors ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 °C to 16 °C at I 25 mol l-1 in aqueous solution. In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths. The kinetic constants for both pathways have been calculated at five temperatures. Activation parameters have also been calculated. The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+. The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.

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