Thio derivatives of β-diketones and their metal chelates. V. Acid dissociation constants of some Monothio-β-diektones and stability constants of anickel(II) and a copper(II) chelate

1966 ◽  
Vol 19 (11) ◽  
pp. 2035 ◽  
Author(s):  
SHH Chaston ◽  
SE Livingstone
Keyword(s):  
Stability Constants ◽  
Mole Fraction ◽  
Dissociation Constants ◽  
Metal Chelates ◽  
Acid Dissociation ◽  
Acid Dissociation Constants ◽  
Water Solutions ◽  
Acetyl Acetone ◽  
The Stability ◽  
Derivatives Of

The acid dissociation constants (PKD) of the monothio derivatives of acetyl-acetone, dibenzoylmethane, and 3,3,3-trifluoro-1-(2- thenoyl)acetone, viz. 4-mercap-topent-3-en-2-one (I), 3-mercapto-1,3- diphenylprop-2-en-1-one (II), and 1,1,1-trifluoro-4-mercapto-4-(2- thienyl)but-3-en-2-one (III), were determined in dioxan/water solutions with varying mole fraction (n2) of dioxan. Over a range of n2 from 0.18 to 0.44 the values of pKD were found to vary linearly with n2 as given by the equations: (I) pKD = 5.7+12.0n2; (II) pKD = 7.0+10.9n2; (III) pKD = 3.55 + 9.2n2. The thio derivatives (I), (II), and (III) have pKD values 2.0-2.7 log units lower than their oxygen analogues. The logarithm of the stability constants (log β2) for the nickel(II) and copper(II) complexes of (II) were found to be 21.7 and 22.2, respectively. For both complexes K2 > K1. Comparison with the stability constants of the dibenzoylmethane complexes shows that for nickel(II) the complex of the monothio-β-diketone is more stable than that of the β-diketone while the converse is true for copper(II).

Substituierte 2-Chloracetessigsäureanilide und ihre Metallchelate / Substituted 2-chloroacetoacetanilides and their metal chelates

1970 ◽  
Vol 25 (12) ◽  
pp. 1386-1388 ◽  
Author(s):  
A. Kettrup ◽  
J. Abshagen
Keyword(s):  
Stability Constants ◽  
Chelating Agents ◽  
Dissociation Constants ◽  
Metal Chelates ◽  
Ph Measurements ◽  
The Stability ◽  
Copper Chelates

The preparation of 2-chloroacetoacetanilides and the preparation of their metal chelates is described.The dissociation constants of the chelating agents and the stability constants of the copper chelates were determined by potentiometric pH-measurements

Decomposition of some cyclic dithiocarbamates

1970 ◽  
Vol 48 (14) ◽  
pp. 2204-2209 ◽  
Author(s):  
Ronald R. Vandebeek ◽  
Serge J. Joris ◽  
Keijo I. Aspila ◽  
Chuni L. Chakrabarti
Keyword(s):  
Dielectric Constant ◽  
Dissociation Constants ◽  
Acid Dissociation ◽  
Acid Molecule ◽  
Decomposition Rates ◽  
Acid Dissociation Constants ◽  
Ring Strain ◽  
Relative Stabilities ◽  
Ph Values ◽  
The Stability

The stability of some cyclic N,N-disubstituted dithiocarbamates has been studied by the analysis of the decomposition rates at different pH values. It is concluded that the most important factors which determine the relative stabilities of three cyclic dithiocarbamates (DTC) are the solvation of the DTC acid molecule and the ring strain associated with the substituents. This has been proven by a study of (a) the decomposition rates as a function of the dielectric constant of the medium, (b) order of the stability, and (c) activation energy.The molar absorptivities and the apparent acid dissociation constants have been determined for pyrrolidine-, piperidine-, and hexamethylene-dithiocarbamates.

Thio derivatives of β-diketones and their metal chelates. XI. Stability constants of nicke(II), copper(II). zinc(II), cadniium(II), and lead(II) chelates of two monothio-β-diketones

1969 ◽  
Vol 22 (7) ◽  
pp. 1363 ◽  
Author(s):  
SE Livingstone ◽  
EA Sullivan
Keyword(s):  
Stability Constants ◽  
Water Solution ◽  
Supporting Electrolyte ◽  
Nickel Complexes ◽  
Metal Chelates ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Chloro Complexes ◽  
Lead And Cadmium ◽  
Derivatives Of

The acid dissociation constant (pKD) of the monothio derivative of benzoyl-acetone, viz. 3-mercapto-1-phenylbut-2-en-1-one (I), was found to be 10.43 in 74.5 vol. % dioxan-water solution. Stoicheiometric stability constants (log kn) of five metal chelates of (I) and of the monothio derivative of dibenzoylmethane, viz. 3-mercapto-1,3- diphenylprop-2-en-1-one (II), have been measured in 74.5 vol. % dioxan- water solution with both chloride and perchlorate as supporting electrolyte. ��� With chloride as supporting electrolyte the values obtained for log kav are as follows: with ligand (I), copper(II) 10.11, nickel(II) 9.25, zinc(II) 6.68, lead(II) 6.06, cadmium(II) 6.12; with ligand (II), copper(II) 10.66, nickel(II) 10.20, zinc(II) 7.44, lead(II) 7.11, cadmium(II) 6.90. With perchlorate as supporting electrolyte zinc, lead, and cadmium give values of log kav which are 1.5-1.9 units greater. The thermodynamic stability constants (logKn) were calculated from the stoicheiometric constants by use of the equations ���������� Log K1 = logk1 + 2.30������� logK2 = log k2 + 1.15 For the copper and nickel complexes of both (1) and (II) log Kav is greater than pKD; such a situation has been reported in only a few instances. ��� From the data obtained with chloride as a supporting medium, approximate stoicheiometric stability constants were calculated for the chloro complexes MCl+ (M = Zn, Cd, Pb) in 74.5 vol. % dioxan. The values obtained were: ZnCl+, 5.0; CdCl+, 5.7; PbCl+, 5.0.

2,3-Dioximes of Various Substituted Acetoacetamides and Their Metal Chelates

1974 ◽  
Vol 52 (4) ◽  
pp. 661-666 ◽  
Author(s):  
Antonius Kettrup ◽  
Klaus Striegler
Keyword(s):  
Stability Constants ◽  
Dissociation Constants ◽  
Metal Chelates ◽  
Amide Group ◽  
Ph Measurements ◽  
The Stability

Methods of preparing 2,3-dioximes of various substituted acetoacetamides are presented. The dissociation constants of these compounds and the stability constants of their metal chelates were determined by potentiometric pH measurements. The influence of the substituents of the amide group on the change of stability is discussed.

3-Monoxime substituierter Acetessigsäureamide als Chelatbildner / 3-Monoximes of Substituted Acetoacetamides as Chelating Agents

1973 ◽  
Vol 28 (1-2) ◽  
pp. 86-89 ◽  
Author(s):  
A. Kettrup ◽  
Th. Neustadt
Keyword(s):  
Stability Constants ◽  
Chelating Agents ◽  
Dissociation Constants ◽  
Metal Chelates ◽  
Amide Group ◽  
Ph Measurements ◽  
The Stability

The preparation of 3-monoximes of different substituted acetoacetamides is described. The dissociation constants of these compounds and also the stability constants of their metal chelates were determined by potentiometric pH-measurements. The change of stability constants by the substituents of the amide group is interpreted.

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