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The interaction of 3,3-bis(1-methylimidazol-2-yl)propionate (BIMP) with dimethyltin(IV) dichloride (DMT), dibutyltin(IV) dichloride (DBT), and diphenyltin(IV) dichloride (DPT) is investigated at 25°C and 0.1 M ionic strength in water for dimethyltin(IV), and in a 50% dioxane-water mixture for dibutyltin(IV) and diphenyltin(IV). The stepwise formation constants of the 1 : 1 and 1 : 2 complexes formed in solution are calculated from potentiometric measurements using the nonlinear least-square program MINIQUAD-75. The concentration distribution of the various complex species is evaluated as a function of pH. Displacement reactions of the coordinated 3,3-bis(1-methylimidazol-2-yl)propionate by inosine and inosine-5'-monophosphate are investigated from calculations based upon equilibrium properties.

Pd(deen)Cl2 and Pd(deen)(CBDCA) complexes, where deen=N,N-diethylethylenediamine and CBDCA=1,1-cyclobutanedicarboxylate, were synthesized and characterized by elemental analysis and spectroscopic techniques. The stoichiometry and stability of the complexes formed between various biologically relevant ligands (amino acids, peptides, DNA constituents and dicarboxylic acids) and [Pd(deen)(H2O)2]2+ were investigated at 25 °C and 0.1 M ionic strength. The speciation diagrams of the complexes formed in solutions are evaluated. The mode of coordination of glycylglycine is investigated by spectrophotometric measurements. The equilibrium constants for the displacement of coordinated ligands as inosine, glycine or methionine by mercaptoethylamine are calculated. The results are expected to contribute to the chemistry of antitumour agents., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The complexing properties of nitrilo-tris(methylphosphonic acid) (NTP) with cadmium(II) were investigated pH-metrically at 25 degrees C and at ionic strength of 0.1 mol dm(-3) (NaNO3). Stoichiometry and stability constants for the complexes formed are reported. Cadmium (II) forms Cd(NTP)(4-) and the corresponding hydroxy complexes. The ternary complexes are formed in a stepwise mechanism whereby NTP binds to cadmium(II), followed by coordination of amino acids, peptides or DNA. The concentration distribution of the various complex species has been evaluated.

The reaction of dimethyltin(IV) dichloride (DMT) with homopiperazine (HPIP) was studied. The equilibria of the complexes formed in solution were investigated. The complexes detected are of 1:1 stoichiometry in addition to the protonated and hydrolysed species. The complex formation constants were determined by the use of potentiometric technique and the non-linear computer program Miniquad-75. The dielectric constant effect of the reaction medium on the formation of the complexes was investigated. Formation constants of the complexes were determined at different temperatures and the thermodynamic parameters as ΔH° and ΔS° were estimated and discussed. The ternary complexes of dimethyltin(IV) with HPIP and DNA constituents are formed by a simultaneous mechanism. Their formation constants were determined. The speciation diagrams of the binary and mixed-ligand complexes were evaluated. [ABSTRACT FROM AUTHOR]

[Pd(BHEP)Cl2] and [Pd(BHEP)(CBDA)] complexes, where BHEP = 1,4-bis(2-hydroxyethyl)piperazine and CBDA = cyclobutanedicarboxylate, were synthesized and characterized. [Pd(BHEP) (CBDA)] crystallizes in space group P21, a = 9.5740(8) Å, b = 9.4700(7) Å, c = 9.7890(10) Å, α = 90.00°, β = 113.360(5)°, γ = 90.00°, V = 814.78(13) Å3, Z = 2. The palladium center has a typical square planar geometry with tetrahedral distortion. DFT calculations show good agreement between theoretical and X-ray data. The stability constants and stoichiometry of the complexes formed between various dicarboxylic acids and [Pd(BHEP)(H2O)2]2+ were studied. Dicarboxylic acids form 1:1 and protonated complexes. Inosine forms 1:1, 1:2 and the protonated form of 1:1 complexes. The temperature effect on the formation constant of the cyclobutanedicarboxylate complex was investigated. The hydrolysis of [Pd(BHEP)(H2O)2]2+ and complex formation with cyclobutanedicarboxylic acid are exothermic processes. [ABSTRACT FROM AUTHOR]

The complex formation equilibria in the reaction of [Pd(en)(H2O)2]2+with 4,4′-bipiperidine (Bip) and DNA constituents such as inosine, inosine-5′-monophosphate, uracil, uridine, thymine, and thymidine were investigated at 25 °C and 0.1 M ionic strength. The [(H2O)(en)Pd(Bip)Pd(en)(H2O)]4+complex and its hydrolyzed species were formed. Substitution of coordinated water by inosine (Ino) as DNA constituent formed the complexes [(Ino)(en)Pd(Bip)Pd(en)(H2O)]3+and [(Ino)(en)Pd(Bip)Pd(en)(Ino)]2+. The formation of the binuclear complexes was further supported by spectral measurements. The formation constants of all possible mono- and binuclear complexes were determined and their speciation diagrams were evaluated. Binuclear complexes involving 4,4′-bipiperidine linkage of two Pd(en)2+species were investigated. The binding of DNA constituents to the binuclear complex was studied. [ABSTRACT FROM AUTHOR]

Abstract: Pd(DHP)Cl2 and Pd(DHP)(CBDCA) complexes (DHP=1,3-diamino-2-hydroxopropane and CBDCA=1,1-cyclobutanedicarboxylate), were synthesized and characterized by elemental analysis, IR and NMR spectral measurements. The coordination of [Pd(DHP)(H2O)2]2+ with some selected bio-relevant ligands, containing different functional groups was investigated. The ligands used are amino acids, peptides, DNA constituents and dicarboxylic acids. Stoichiometry and stability constants of the complexes formed are reported at 25°C and 0.1M ionic strength. The results show the formation of 1:1 complexes with amino acids and dicarboxylic acids. DNA constituents form 1:1 and 1:2 complexes. Peptides form both 1:1 complexes and the corresponding deprotonated amide species. The effect of chloride ion concentration and dioxane on the acid dissociation constants of 1,1-cyclobutane dicarboxylic acid (CBDCAH2) and the formation constant of its complex with Pd(DHP)2+ was reported. The equilibrium constants for the displacement of coordinated ligands as uracil, glycine or methionine by cysteine are calculated. The results are expected to contribute to the chemistry of antitumour agents. [Copyright &y& Elsevier]

Pd(DME)Cl2 complex was synthesized and characterized, where DME is 2-{[2-(dimethylamino)ethyl]-methylamino}ethanol. Stoichiometry and stability constants of the complexes formed between various biologically relevant ligands (amino acids, peptides, DNA constituents, and dicarboxylic acids) and [Pd(DME)(H2O)2]2+ are investigated at 25°C and at constant 0.1 M ionic strength. The effect of dielectric constant of the medium on the stability constant of Pd(DME)-CBDCA complex, where CBDCA is cyclobutanedicarboxylate, is also reported. The concentration distribution diagrams of the various species formed are evaluated. The kinetics of base hydrolysis of amino acid esters coordinated to Pd(DME)2+ complex is investigated. The effect of the temperature on the kinetics of base hydrolysis of glycine methyl ester complex is studied. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 608–618, 2010 [ABSTRACT FROM AUTHOR]

The complex formation reactions of [Cu(NTP)(OH 2 )] 4- (NTP  =  nitrilo-tris(methyl phosphonic acid)) with some selected bio-relevant ligands containing different functional groups, are investigated. Stoichiometry and stability constants for the complexes formed are reported. The results show that the ternary complexes are formed in a stepwise mechanism whereby NTP binds to copper(II), followed by coordination of amino acid, peptide or DNA. Copper(II) is found to form Cu(NTP)H n species with n   =  0, 1, 2 or 3. The concentration distribution of the various complex species has been evaluated. The kinetics of base hydrolysis of glycine methyl ester in the presence of copper(II)-NTP complex is studied in aqueous solution at different temperatures. It is proposed that the catalysis of GlyOMe ester occurs by attack of OH - ion on the uncoordinated carbonyl carbon atom of the ester group. Activation parameters for the base hydrolysis of the complex [Cu(NTP)NH 2 CH 2 CO 2 Me] 4- are, ΔH ±   =  9.5  ±  0.3  kJ  mol -1 and ΔS ±   =  -179.3  ±  0.9  J  K -1   mol -1 . These show that catalysis is due to a substantial lowering of ΔH ± . [ABSTRACT FROM AUTHOR]

The interaction of the tri-n-propyltin(IV) (TPT) with some selected bio- ligands having a variety of model functional groups were investigated using potentiometric technique at 25°C and 0.1 M ionic strength in 50% v/v dioxane/water mixture. TPT is hydrolyzed to give [(C3H7)3SnOH], [(C3H7)3Sn(OH)2], and [((C3H7)3Sn)2OH]+. Amino acids and DNA constituents form 1:1 and 1:2 complexes. Peptides form 1:1 complexes and the corresponding deprotonated amide species. The protonated complexes are formed with amino acids, peptides and some DNA constituents. The hydrolysis constants and the stepwise formation constants of the complexes formed in solution were calculated using the nonlinear least-square program MINIQUAD-75. The participation of different ligand functional groups in binding to organotin is discussed. The speciation diagrams of the various complex species were evaluated as a function of pH. [ABSTRACT FROM AUTHOR]

Binary and ternary complexes of Cu(II) involving imino-bis(methyl phosphonic acid) (IdP) abbreviated as H4A and some selected bio-ligands, amino acids, peptides and DNA constituents (L), were examined. Cu(II) forms CuA and CuAH complexes with IdP. Ternary complexes are formed in a stepwise mechanism whereby iminodiphosphonic acid binds to Cu(II), followed by coordination of amino acid, peptide or DNA. The concentration distribution of the various complex species has been evaluated. The kinetics of base hydrolysis of glycine methyl ester in the presence of Cu(II)-IdP was studied in aqueous solution at different temperatures, and in dioxane-water solutions of different compositions at 25°C. The activation parameters are evaluated and discussed. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and biological evaluation of [Pd(L)(OH 2)Cl] complex (where L = 2,2′-(pyridin-2-ylmethylene)bis(5,5-dimethylcyclohexane-1,3-dione) as a novel promising anticancer candidate. The complex was characterized by single-crystal X-ray diffraction and other various spectroscopic techniques. Besides, the optimized structure was determined through DFT calculations revealing that the coordination geometry of [Pd(L)(OH 2)Cl] complex is square planar. The binding propensity of [Pd(L)(OH 2)Cl] complex with DNA and BSA was assessed by the spectrophotometric method. The antimicrobial profile of the ligand and its [Pd(L)(OH 2)Cl] complex was screened against clinically important bacterial strains. [Pd(L)(OH 2)Cl] complex showed promising activity against these microorganisms. Pd(L)(OH 2)Cl] complex exhibited a potent antiproliferative potential compared to its ligand against different human cancer cells (A549, HCT116, MDA-MB-231, and HepG2) with less toxic effect against normal cells (WI-38). Additionally, [ Pd(L)(OH 2)Cl] complex exerted its anticancer effects against the most responsive cells (HCT116 cells; IC 50 = 11 ± 1 μM) through suppressing their colony-forming capabilities and triggering apoptosis and cell cycle arrest at S phase. Quantitative PCR analysis revealed a remarkable upregulation of the mRNA expression level of p53 and caspase-3 by 4.8- and 5.9-fold, respectively, relative to control. Remarkable binding properties and non-covalent interactions between L and its [Pd(L)(OH 2)Cl] complex with the binding sites of different receptors including CDK2, MurE ligase, DNA, and BSA were established using molecular docking. Based on our results, [Pd(L)(OH 2)Cl] complex is an intriguing candidate for future investigations as a potential anticancer drug for the treatment of colon cancer. [Pd(L)(OH 2)Cl] complex was synthesized and characterized by X-ray crystallography. [Pd(L)(OH 2)Cl] complex binding potentials towards different receptors were evaluated using docking. Anticancer activity was evaluated using MTT, apoptotic, and cell cycle assays. Caspase-3 and p53 expression levels were upregulated by 4.8- and 5.9-fold compared to control cells using qRT-PCR analysis. [Display omitted] • A new palladium complex was synthesized and confirmed through X-ray investigation. • [Pd(L)(OH 2)Cl] complex showed good antibacterial effects and DNA/BSA-binding potentials. • The complex revealed a potent cytotoxicity against different human cancer cells. • Caspase-3 and p53 expression levels were significantly upregulated using qPCR analysis. • Docking showed binding properties of [Pd(L)(OH 2)Cl] complex towards different receptors. [ABSTRACT FROM AUTHOR]