Synthesis, characterization, and thermodynamics of tertiary phosphine cobalt(III) Schiff-base complexes

2001 ◽  
Vol 79 (9) ◽  
pp. 1360-1365 ◽  
Author(s):  
Mozaffar Asadi ◽  
Ali Hossein Sarvestani
Keyword(s):  
Schiff Base ◽  
Ionic Strength ◽  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Schiff Base Complex ◽  
Axial Ligand ◽  
Adduct Formation ◽  
Schiff Base Complexes ◽  
Tertiary Phosphine ◽  
The Stability

[Co(5-nitroSalen)(PBu3)]ClO4·H2O and [Co(Salpd)(PBu3)]ClO4·H2O were synthesized and characterized. The stability constants and the thermodynamic parameters were measured spectrophotometrically for 1:1 adduct formation of [CoL(PBu3)]ClO4·H2O, (L = Salen, 5-nitroSalen, Salpd), and [Co(Salen)(PMe2Ph)]ClO4·H2O as acceptors with P(OR)3, (R = Me, Et, i-Pr) as donors, in acetonitrile solvent and in constant ionic strength (I = 0.01 M) and at various temperatures. The trend of the reactivity of cobalt(III) Schiff-base complexes with PBu3 axial ligand toward a given donor is as follows: 5-nitroSalen > Salen > Salpd.Also, the following reactivity trend of the donors toward a given cobalt(III) Schiff-base complex is in the operation: P(O-i-Pr)3 > P(OEt)3 > P(OMe)3.Key words: cobalt(III) Schiff-base complexes, thermodynamic parameters, trialkylphosphite, adduct complexes, stability constants.

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.

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 Spectrophotometric Study of Adduct Formation Between [Co(Salen)PPh3]ClO4.H2O and [Co(7,7'-Dimethylsalen)PPh3]ClO4.H2O with Amines Donors in Acetonitrile

2010 ◽  
Vol 7 (4) ◽  
pp. 1421-1425
Author(s):  
Mahmood Niad ◽  
Khosro Mohammadi ◽  
Mozaffar Asadi
Keyword(s):  
Schiff Base ◽  
Ionic Strength ◽  
Room Temperature ◽  
Sodium Perchlorate ◽  
Spectrophotometric Study ◽  
Adduct Formation ◽  
Schiff Base Complexes ◽  
Constant Ionic Strength ◽  
Equilibrium Quotient ◽  
Donor And Acceptor

The equilibrium quotient of the adduct formation of [Co(Salen)PPh3]ClO4.H2O and [Co(7,7'-dimethylSalen)PPh3]ClO4.H2O, as acceptor with amines donors are studied by spectrophotometer. Thermodynamics of these pentacoordinate cobalt(III) Schiff-base complexes have been examined withn-butylamine,sec-butylamine,tert-butylamine, benzylamine and diethylamine in constant ionic strength of 0.1 M sodium perchlorate and acetonitrile solvent at room temperature. We aimed to investigate the effects of different electronic and steric situations of donor and acceptor by comparing their equilibrium quotient for any adduct.

Thermodynamics of triaryltin chloride adduct complexes

2001 ◽  
Vol 79 (1) ◽  
pp. 70-74
Author(s):  
Mozaffar Asadi ◽  
Khosrow Aein Jamshid
Keyword(s):  
Thermodynamic Parameters ◽  
Stability Constants ◽  
Thermodynamic Data ◽  
Lewis Acids ◽  
Mixed Solvent ◽  
Adduct Formation ◽  
Lewis Bases ◽  
Water Solvent ◽  
The Stability ◽  
Chloride Adduct

The stability constants and the thermodynamic data were measured spectrophotometerically for 1:1 adduct formation of triaryltin chlorides, where aryl groups are p-chlorophenyl, phenyl, p-, m-, and o-tolyl, as Lewis acids, with chloride and bromide ions, as Lewis bases, in 50% v/v ethanol-water solvent. The stability constants and the thermodynamic parameters trend, confirmed the following softness trend of tin(IV) in the triaryltin chlorides:(p-, m-, o-tolyl)3SnCl > (phenyl)3SnCl > (p-chlorophenyl)3SnClKey words: tin(IV) complexes, thermodynamic parameters, mixed solvent, adduct formation.

scholarly journals Stability Studies of Transition Metal Chelates of 5-Bromosalicylidene-4-methoxyaniline andSalicylidene-2,3-dimethylaniline as Ligands

2011 ◽  
Vol 8 (4) ◽  
pp. 1911-1915
Author(s):  
N. G. Nadkarni ◽  
K. V. Mangaonkar
Keyword(s):  
Ionic Strength ◽  
Transition Metal ◽  
Stability Constants ◽  
Metal Chelates ◽  
Ternary Complexes ◽  
Water Medium ◽  
Stability Studies ◽  
Binary And Ternary Complexes ◽  
Transition Metal Chelates ◽  
The Stability

Binary and ternary complexes of the type M-Y and M-X-Y [M = Mn(II), Ni(II), Cu(II) and Zn(II); X = 5-bromosalicylidene-4-methoxyaniline and Y = salicylidene-2,3-dimethylaniline] have been examined pH-metrically at 27±0.5°C and at constant ionic strength, μ = 0.1 M (KCl) in 75 : 25(v/v) 1,4-dioxne-water medium. The stability constants for binary (M-Y) and ternary (M-X-Y) systems were calculated.

Interligand interaction in ternary complexes of Zn(II) and Cd(II) with dipeptides and aminoacids

1994 ◽  
Vol 72 (4) ◽  
pp. 1107-1110 ◽  
Author(s):  
Alexander Varghese Vaidyan ◽  
Pabitra K. Bhattacharya
Keyword(s):  
Ionic Strength ◽  
Aqueous Medium ◽  
Computer System ◽  
Stability Constants ◽  
Ternary Complexes ◽  
Binary And Ternary Complexes ◽  
The Stability ◽  
Interligand Interaction

The stability constants of binary and ternary complexes [MA], [Ma2], and [MAL] (where M = Zn(II) or Cd(II); A = glycylglycine, glycyl L-alanine, glycyl L-leucine; L = α-alanine phenylalanine, tyrosine, tryptophan, or L-histidine) in aqueous medium have been determined potentometrically at 25 °C and an ionic strength of 0.2 M NaClO4 (0.2 mol dm−3) using a computer system. It is observed that Δ log K of MAL complexes has low negative or positive values. Probable reasons have been discussed.

Synthesis, Characterization, and Antimicrobial Activities of New Organic-Inorganic Hybird Compound Based on Polyoxovanadate and Metal-Schiff-Base Complex

2015 ◽  
Vol 1105 ◽  
pp. 215-219
Author(s):  
Qiong Wu ◽  
Xiao Lin Ji ◽  
Lu Jing ◽  
Hong Ping Ju ◽  
Hai Wang
Keyword(s):  
Schiff Base ◽  
Human Cancer ◽  
Synergetic Effect ◽  
Schiff Base Complex ◽  
Antimicrobial Activities ◽  
Schiff Base Complexes ◽  
X Ray Diffraction ◽  
Base Complex ◽  
X Ray ◽  
Vis Spectroscopy

The reaction of polyoxovanadate and metal-Schiff base complex resulted in the formation of a new organic-inorganic hybrid compounds with the formula Na2[Mn (Salen)(H2O)2]4[V10O28]·9H2O (1) (salen=N,N’-ethylene-bis (salicylideneiminate). Compound 1 have been structurally characterized by IR, UV-vis spectroscopy and single crystal X-ray diffraction. Crystal data for 1: Triclinic, P-1, a=14.1123(3)Å, b=13.9397(7) Å, c=14.2564(5)Å, α=65.4160(9)°, β=81.3920(6)°, γ=89.5740(7) °. Structural analyses revealed that compound 1 represent a rare example of isopolyoxovanadate based metal-Schiff-base complexes, moreover, this is the first POM based metal Schiff-base complex isolated in aqueous solution medium, which may also propose a green chemical way to the synthesis of POM based hybrid. Compare with isopolyoxovanadate precusor Na6 [V10O28], compound 1 exhibit higher antimicrobial activities against human cancer cell, the phenomenon can be explained by the synergetic effect between POM and Schiff-base complex.

Schiff base equilibria. V. Beryllium complexes of N-ethylsalicylideneimine

1966 ◽  
Vol 19 (11) ◽  
pp. 2101 ◽  
Author(s):  
RW Green ◽  
RJ Sleet
Keyword(s):  
Schiff Base ◽  
Distribution Coefficient ◽  
Stability Constants ◽  
Formation Constant ◽  
Mixed Complex ◽  
High Ph ◽  
The Stability ◽  
Hydrolysis Of ◽  
Beryllium Complexes

The formation constant and pK at 25� of the Schiff base N- ethylsalicylideneimine (HL) have been found by spectrophotometry to be 2.75x104 and 11.8 respectively. The distribution coefficient of the base from water into toluene is 160. The stability constants of the beryllium complexes determined by solvent distribution are logβ1 10.4 and log β2 18.3, and the distribution coefficient of BeL2 is 260. At high pH the equilibria are complicated by hydrolysis of the Be2+ ion and by formation of the mixed complex, BeL(OH)-2. The latter is formed according to the reaction BeL(H2O)+2 ↔ BeL(OH)-2+2H+ with logKm2 -18.4.

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