Tripropyltin(IV) Complexes with some Selected Bioligands in 50 % V/V Dioxane/Water Mixture (original) (raw)
Related papers
Equilibrium Studies of Organotin(IV) Complexes of Peptides
Main Group Metal Chemistry, 1999
The interaction of dimethyltin(IV), diethyltin(IV) and trimethyltin(IV) with some selected peptides was investigated at 25°C and ionic strength 0.1 Μ NaN0 3 by a Potentiometrie technique. The peptides are bound to dialkyltin(IV) by carboxylate, deionized amide and amino groups. However, peptides are bound to trimethyltin(IV) by the amino group. The effect of the pKa values of the peptides on the stability constants of their complexes were elucidated. The concentration distribution of the complexes in solution was evaluated.
Interaction of Diphenyltin(IV) Dichloride with Some Selected Bioligands
CHEMICAL & PHARMACEUTICAL BULLETIN, 2001
Among organotins, dialkyl derivatives exhibit greater antitumour activity than the corresponding mono-, tri-, and tetraalkyl derivatives. 2) The activity of the tri-or tetra-alkyl derivatives may be explained by dealkylation in vivo which yields the corresponding active dialkyl derivatives. If one ranks specific alkyl organotins in terms of antitumour activity of the parent compounds, the diethyl and diphenyl derivatives have the highest activity in vivo provided that one takes no cognizance of their toxicity. 3) Accepting the hypothesis that R 2 Sn 2ϩ are the usual active species for the antitumour action of organotins, 4) a good antitumour agent should be easily dissociable following administration to animals. This requires weak bonds between tin and the donor atom of the coordinated organic compounds which are readily hydrolysable. If the compound is hydrolytically unstable, the R 2 Sn moiety will be released too soon, and if it is too stable, it may be released too slowly and consequently lower activity will be observed. Such a mechanism also adds weight to the proposition for the R 2 SnX 2 L 2 adducts, where it was shown that relatively long Sn-N bonds were a requirement for activity, and that predissociation of the ligand L 2 may be an important feature of the mode of action of this particular class of compounds. Therefore, there is a relationship between the stability of the organotin compounds and their antitumour activity. In continuation of our studies on organotin(IV) complexes, 5-11) the present paper aims to study the diphenyltin-(IV) complex formation equilibria with some selected bioligands, with the hope that such types of coordinating ligands might possess favorable properties, possibly as carriers in body fluids. Experimental Materials and Reagents Diphenyltin(IV) dichloride (DPT) was obtained from Merck Chem. Co. The ligands used were glycine, proline, methionine, serine, histidine, histamine, ornithine, lysine, aspartic acid, glutamic acid, mercaptoethylamine, mercaptopropionic acid, penicillamine, glutathione, cyclobutane dicarboxylic acid (CBDCA), oxalic acid, malonic acid, succinic acid, adipic acid, fumaric acid, glycylglycine, glycylalanine, glycylleucine, glycylmethionine, glutamine and aspargine. These were supplied by Fluka Chem. Co. The DPT was converted to the perchlorate form by suspension in dioxane, addition of 1.98 eq of AgClO 4 and stirring over night. The precipitate (AgCl) was filtered and the resulting final solution was diluted to a 75% dioxane-water solution. The concentration of DPT was checked potentiometrically. Solutions of histidine, ornithine, lysine were prepared in the protonated form by dissolving in equimolar HNO 3 solution. Carbonate free sodium hydroxide stock solutions were prepared by diluting the contents of British Druy House (BDH) concentrated volumetric solu-* To whom correspondence should be addressed.
Equilibrium studies of the diorganotin(IV) complexes with some amino acids and related compounds
Talanta, 1996
The interaction of dimethyltin(lV) and diethyltin(IV) cations with water and some amino acids and related compounds was investigated at 25°C and ionic strength 0.1 M NaNO, using a potentiometric technique. The results showed the formation of I:1 and 1:2 (organotin:ligand) complexes and the corresponding stability constants were determined. The participation of different ligand functional groups in binding to organotin is discussed. The effect of the pK, value of the respective ligand on the stability constant of its complex species was elucidated. The concentration distribution of the complexes in solution was evaluated.
Equilibrium studies of organotin(IV) complexes with vitamin B6
Talanta, 1997
The complex-formation equilibria of dimethyltin(IV), trimethyltin(IV) and tributyltin(IV) with pyridoxamine were investigated in dioxane-water mixtures and at different temperatures using a potentiometric technique. The stepwise formation constants of the complexes formed in solution were calculated using the non-linear least-square program MINIQUAD-75. The effect of dioxane as a solvent on the protonation constants of pyridoxamine and the formation constants of organotin(IV) complexes was discussed. The thermodynamic parameters AH ° and AS ° calculated from the temperature dependence of the equilibrium constants were investigated. The concentration distribution of the various complex species was evaluated as a function of pH.
Potentiometric Studies on Binary Complexes of Catecholic Compounds with Organotin ( IV ) Cations
2015
Potentiometric studies are performed in aqueous solution in order to characterize the interaction of dimethyltin(IV) [DMT] and Trimethyltin(IV) [TMT] cation with catecholic ligands. Experiments are performed at three different temperatures (20oC, 30oC and 40oC) and at three ionic strengths (μ = 0.05 ,0.10 and 0.15 M). The analysis of stability constant (log ß) and stability order of investigated metal-ligand species [MHL, ML, ML(OH) and ML(OH)2 ] are obtained by using computer programme SCOGS(stability constants of generalized species). The complex species formed are water soluble in the experimental pH range (3.0–10.5). Thermodynamic stability constants along with thermodynamic parameters i.e. standard free energy change (∆Go) enthalpy change (∆Ho) and entropy change(∆So) are calculated for all the systems. The thermodynamic stabilities of DMT species are found to be more than TMT (IV) species. High stability of 4-methylcatechol complexes is attributed to greater basicity.
Synthesis and characterization of organotin complexes with 2- …
Applied Organometallic Chemistry
By reaction of diphenyltin(1V) chloride and triphe- nyltin(1V) hydroxide with esters of the 2- mer captopyridine-5-carboxylic acid NH(CS)CHCHC (COOR )C'H (HTNME, R = methyl; HTNEE, R = ethyl; HTNIPE, R = isopropyl) the complexes Ph,Sn(L), Ph,SnCI(L) (L = TNME, TNEE ...
Journal of Inorganic Biochemistry, 1992
The aqueous solution chemistry of the trimethyltin(IV) species and their complexes with amino acids has been studied by potentiometric technique. The results showed the formation of 1:l complexes, and the corresponding stability constants were determined. The amino acid was bound to (CH,),Sn(IV) as a monodentate ligand. The effect of the pK, value of the respective ligand on the stability constant of its complex species with the organotin(IV) ion was elucidated. The concentration distribution of the complexes in solution was evaluated.