Advanced

Thermodynamics for complex formation between palladium(II) and oxalate

Pilny, Radomir; Lubal, Premysl and Elding, Lars Ivar LU (2014) In Dalton Transactions 43(32). p.12243-12250
Abstract
Complex formation between [Pd(H2O)(4)](2+) and oxalate (ox = C2O42-) has been studied spectrophotometrically in aqueous solution at variable temperature, ionic strength and pH. Thermodynamic parameters at 298.2 K and 1.00 mol dm(-3) HCIO4 ionic medium for the complex formation [Pd(H2O)(4)](2+) + H(2)ox (sic) Pd(H2O)(2)(ox)] + 2H(3)O(+) with equilibrium constant K-1H (in mol dm(-3)) are logio K-1,K-H = 3.38 +/- 0.08, Delta H-1(0) = -33 +/- 3 kJ mol(-1), and Delta S-1(0) = 48 +/- 11 J K-1 morl, as determined from spectrophotometric equilibrium titrations at 15.0, 20.0, 25.0 and 31.0 degrees C. Thermodynamic overall stability constants beta(0)(n) (in (mol dm-(3))(-n), n = 1,2) for [pd(H2O)(2)(ox)] and [Pd(ox)(2])(2) at zero ionic strength and... (More)
Complex formation between [Pd(H2O)(4)](2+) and oxalate (ox = C2O42-) has been studied spectrophotometrically in aqueous solution at variable temperature, ionic strength and pH. Thermodynamic parameters at 298.2 K and 1.00 mol dm(-3) HCIO4 ionic medium for the complex formation [Pd(H2O)(4)](2+) + H(2)ox (sic) Pd(H2O)(2)(ox)] + 2H(3)O(+) with equilibrium constant K-1H (in mol dm(-3)) are logio K-1,K-H = 3.38 +/- 0.08, Delta H-1(0) = -33 +/- 3 kJ mol(-1), and Delta S-1(0) = 48 +/- 11 J K-1 morl, as determined from spectrophotometric equilibrium titrations at 15.0, 20.0, 25.0 and 31.0 degrees C. Thermodynamic overall stability constants beta(0)(n) (in (mol dm-(3))(-n), n = 1,2) for [pd(H2O)(2)(ox)] and [Pd(ox)(2])(2) at zero ionic strength and 298.2 K, defined as the equilibrium constants for the reaction Pd2+ nox(2) (sic) Pd(ox)](2-2n) (water molecules omitted) are logio beta(0)(1) = 9.04 +/- 0.06 and logio beta(0)(1) = 13.1 +/- 0.3, respectively, calculated by use of Specific Ion Interaction Theory from spectrophotometric titrations with initial hydrogen ion concentrations of 1.00, 0.100 and 0.0100 mol dm-3 and ionic strengths of 1.00, 2.00 or 3.00 mol dm-3. The values derived together with literature data give estimated overall stability constants for Pd(o) compounds such as Pd(en)(ox)1 and cis-IPd(NH3)2021, some of them analogs to Pt(s) complexes used in cancer treatment. The palladium oxatato complexes are significantly more stable than palladium(v) complexes with monodentate 0-bonding ligands. A comparison between several different palladium complexes shows that different parameters contribute to the stability variations observed. These are discussed together with the so-called chelate effect. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Complex formation, Palladium, Oxalate
in
Dalton Transactions
volume
43
issue
32
pages
12243 - 12250
publisher
Royal Society of Chemistry
external identifiers
  • wos:000339862000016
  • scopus:84904665681
ISSN
1477-9234
DOI
10.1039/c4dt01062k
language
English
LU publication?
yes
id
62e2616e-7fed-43b5-9c17-eb183463668f (old id 4665691)
date added to LUP
2014-09-25 14:37:23
date last changed
2017-06-28 14:18:00
@article{62e2616e-7fed-43b5-9c17-eb183463668f,
  abstract     = {Complex formation between [Pd(H2O)(4)](2+) and oxalate (ox = C2O42-) has been studied spectrophotometrically in aqueous solution at variable temperature, ionic strength and pH. Thermodynamic parameters at 298.2 K and 1.00 mol dm(-3) HCIO4 ionic medium for the complex formation [Pd(H2O)(4)](2+) + H(2)ox (sic) Pd(H2O)(2)(ox)] + 2H(3)O(+) with equilibrium constant K-1H (in mol dm(-3)) are logio K-1,K-H = 3.38 +/- 0.08, Delta H-1(0) = -33 +/- 3 kJ mol(-1), and Delta S-1(0) = 48 +/- 11 J K-1 morl, as determined from spectrophotometric equilibrium titrations at 15.0, 20.0, 25.0 and 31.0 degrees C. Thermodynamic overall stability constants beta(0)(n) (in (mol dm-(3))(-n), n = 1,2) for [pd(H2O)(2)(ox)] and [Pd(ox)(2])(2) at zero ionic strength and 298.2 K, defined as the equilibrium constants for the reaction Pd2+ nox(2) (sic) Pd(ox)](2-2n) (water molecules omitted) are logio beta(0)(1) = 9.04 +/- 0.06 and logio beta(0)(1) = 13.1 +/- 0.3, respectively, calculated by use of Specific Ion Interaction Theory from spectrophotometric titrations with initial hydrogen ion concentrations of 1.00, 0.100 and 0.0100 mol dm-3 and ionic strengths of 1.00, 2.00 or 3.00 mol dm-3. The values derived together with literature data give estimated overall stability constants for Pd(o) compounds such as Pd(en)(ox)1 and cis-IPd(NH3)2021, some of them analogs to Pt(s) complexes used in cancer treatment. The palladium oxatato complexes are significantly more stable than palladium(v) complexes with monodentate 0-bonding ligands. A comparison between several different palladium complexes shows that different parameters contribute to the stability variations observed. These are discussed together with the so-called chelate effect.},
  author       = {Pilny, Radomir and Lubal, Premysl and Elding, Lars Ivar},
  issn         = {1477-9234},
  keyword      = {Complex formation,Palladium, Oxalate},
  language     = {eng},
  number       = {32},
  pages        = {12243--12250},
  publisher    = {Royal Society of Chemistry},
  series       = {Dalton Transactions},
  title        = {Thermodynamics for complex formation between palladium(II) and oxalate},
  url          = {http://dx.doi.org/10.1039/c4dt01062k},
  volume       = {43},
  year         = {2014},
}