Thermodynamics for complex formation between palladium(ii) and oxalate

2014 ◽  
Vol 43 (32) ◽  
pp. 12243-12250 ◽  
Author(s):  
Radomír Pilný ◽  
Přemysl Lubal ◽  
Lars I. Elding
Keyword(s):  
Complex Formation ◽  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Chelate Effect ◽  
Overall Stability ◽  
Oxalato Complexes

Overall stability constants and thermodynamic parameters for formation of palladium(ii) oxalato complexes have been determined. The chelate effect is discussed.

scholarly journals The Stability Constants and Thermodynamic Parameters of Borate - Carbohydrate Complexes by pH Measurements

2012 ◽  
Vol 25 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Farida Akhtar ◽  
Md Anisur Rahman ◽  
DM Shafiqul Islam ◽  
Md Anamul Hoque
Keyword(s):  
Ionic Strength ◽  
Complex Formation ◽  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Chemical Society ◽  
Ph Measurements ◽  
Negative Contribution ◽  
Exothermic Process ◽  
Different Temperatures ◽  
The Stability

The complexation of borate with carbohydrates was studied potentiometrically at  temperatures 298.15-328.15K in aqueous medium at constant ionic strength, I = 0.1M  KCl. The stability constants (?) and thermodynamic parameters of borate-carbohydrate  complexes were determined using the technique proposed by Verchere and Hlaibi.  Carbohydrates such as D-fructose, D-Sorbitol, D-Mannitol, D-Galactose, D-Glucose and  D-Raffinose were used as ligands in this study. The ?1 values for the complexes at  different temperatures were found to follow the order: D-fructose > D-Sorbitol > DMannitol > D-Galactose > D-Glucose > D-Raffinose. The ?G0 values were found to be  negative and the negative values increased according to the above order. The values of  ?H0 and ?S0 were both negative which indicated that the complex formation was an  exothermic process and the spontaneity of its formation is driven by enthalpic  contribution overcoming the negative contribution of ?S0. DOI: http://dx.doi.org/10.3329/jbcs.v25i1.11766 Journal of Bangladesh Chemical Society, Vol. 25(1), 15-20, 2012

scholarly journals Synthesis, Identification of Co(II), Cu(II) and Ni(II) Complexes with A Schiff Base–Azo Ligand Derived from Imidazol Derivatives, 4- Aminoacetophenon and 4- Chloroaniline and Study Their Physical Properties and Their Thermodynamic Stabilities

2019 ◽  
Vol 27 (3) ◽  
pp. 406-419
Author(s):  
Aesa Farhan
Keyword(s):  
Schiff Base ◽  
Stability Constants ◽  
Diazonium Salt ◽  
Ratio Method ◽  
Element Analysis ◽  
Chelate Effect ◽  
Geometrical Shapes ◽  
Overall Stability ◽  
Mole Ratio Method ◽  
Spontaneous Reaction

The complexes of Co(II), Cu(II) and Ni(II)  were synthesized by using schiff base – azo as a ligand, which were prepared under this study by the reaction between the Schiff base diazonium salt and the imidazole derevitive. They were characterized by element analysis, FTIR spectroscopy and UV.VIS. spectroscopy. Their electric conductivity and magnetic features were determined. Their stepwise and overall stability constants and their thermodynamic data ( ,  and ) were determined. The results showed that all the complexes have paramagnetic features and all of them have good conductivity. The formula of the complexes under this paper were suggested by using the mole ratio method which lead to the formation of (1 : 2) metal : ligand formula for all the complexes. In all the complexes the coordinated sites was through N atoms of the azo groups and N atom of the imidazol ring. The suggested geometrical shapes of the complexes was the octahedral shape due to the ( d2sp3 ) hybridization. Their stepwise stability constants were determined, it was found that for all the complexes they were increased toward the addition of ligand that because of the chelate effect. Their overall stability constants were determined, it was found that for all the complexes were high that because of the chelate effect. Their thermodynamic functions ( ,  and  ) were had negative value, that refer to good stability for the complexes and these results were satisfied with the spontaneous reaction and high stability complexes.

scholarly journals Thermodynamic and detailed kinetic study of the formation of orthophthalaldehyde-agmatine complex by fluorescence intensities

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Khémesse Kital ◽  
Moumouny Traoré ◽  
Diégane Sarr ◽  
Moussa Mbaye ◽  
Mame Diabou Gaye Seye ◽  
...  
Keyword(s):  
Complex Formation ◽  
Thermodynamic Parameters ◽  
Initial Rate ◽  
Reaction Medium ◽  
Standard Entropy ◽  
Step Size ◽  
Formation Reaction ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Complex Formation Process

Abstract The aim of this work is to determine the thermodynamic parameters and the kinetics of complex formation between orthophthalaldehyde (OPA) and agmatine (AGM) in an alkaline medium (pH 13). Firstly, the association constant (Ka) between orthophthalaldehyde and agmatine was determined at different temperatures (between 298 K and 338 K) with a step size of 10 K. Secondly, the thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°),and Gibbs energy (∆G) were calculated, where a positive value of ΔH° (+45.50 kJ/mol) was found, which shows that the reaction is endothermic. In addition, the low value of ΔS°(+0.24 kJ/mol) indicates a slight increase in the disorder in the reaction medium. Furthermore, the negative values of ΔG between −35.62 kJ/mol and −26.02 kJ/mol show that the complex formation process is spontaneous. Finally, the parameters of the kinetics of the reaction between OPA and AGM were determined as follows: when the initial concentration of AGM (5 × 10−6 M) is equal to that of the OPA, the results show that the reaction follows an overall 1.5 order kinetics with an initial rate of 5.1 × 10−7Mmin−1 and a half-life of 8.12 min. The partial order found in relation to the AGM is 0.8. This work shows that the excess of OPA accelerates the formation reaction of the complex.

scholarly journals Potentiometric and spectrophotometric studies of the complexation of Schiff-base hydrazones containing the pyrimidine moiety

2003 ◽  
Vol 68 (10) ◽  
pp. 729-749 ◽  
Author(s):  
H.S. Seleem ◽  
B.A. El-Shetary ◽  
S.M.E. Khalil ◽  
M. Shebl
Keyword(s):  
Schiff Base ◽  
Ionic Strength ◽  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Elemental Analysis ◽  
Mass Spectra ◽  
Dissociation Constants ◽  
The Stability ◽  
Pyrimidine Moiety ◽  
Metal Ligand

Three Schiff-base hydrazones (ONN ? donors) were prepared by condensation of 2-amino-4-hydrazino-6-methylpyrimidine with 2-hydroxyacetophenone 2-methoxybenzaldehyde and diacetyl to yield 2-OHAHP, 2-OMeBHPand DHP respectively. The structures of these ligands were elucidated by elemental analysis, UV, IR, 1H-NMR and mass spectra. The metal?ligand stability constants of Mn2+, Fe3+,Co2+,Ni2+,Cu2+, Zn2+,Cd2+,UO22+ and Th4+ chelates were determined potentiometrically in two different media (75%(v/v) dioxane?water and ethanol?water) at 283, 293, 303 and 313 K at an ionic strength of 0.05 M (KNO3). The thermodynamic parameters of the 1:1 and 1:2 complexes were evaluated and are discussed. The dissociation constants of 2-OHAHP, 2-OMeBHP and DHPligands and the stability constants of Co2+, Ni2 and Cu2+ with 2-OHAHP were determined spectrophotometrically in 75 % (v/v) dioxane?water.

Equilibrium Studies of Alkyltin(IV) Complexes with D-Glucosamine

1997 ◽  
Vol 62 (7) ◽  
pp. 1023-1028 ◽  
Author(s):  
Mohamed M. Shoukry ◽  
Samir M. El-Medani
Keyword(s):  
Complex Formation ◽  
Stability Constants ◽  
Acid Base ◽  
Complex Formation Equilibria ◽  
Equilibrium Studies ◽  
Formation Equilibria ◽  
Effects Of Temperature ◽  
The Stability

The acid-base and complex-formation equilibria involving glucosamine and its complexes with alkyltin(IV) chlorides have been studied by potentiometric technique. The results prove to a formation of 1 : 1 complex with trialkyltin(IV) and both 1 : 1 and 1 : 2 complexes with dialkyltin(IV) species. The stability constants in water were determined, the effects of temperature (from 15 to 35 °C) and ethanol (up to 88 vol.%) was studied and the speciation of the complexes was resolved.

Sign in / Sign up

Export Citation Format

Share Document