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The interaction of dibutyltin(IV) dichloride (DBT) with 1,4-diazacycloheptane (homopiperazine, HP) was investigated. In solutions, the complexes formed a 1:1 complex, its protonated and hydrolyzed forms. The formation constants of the complexes and thermodynamic parameters as ΔH° and ΔS° were estimated. The optimization of the structure of the (Bu)2Sn(HP)Cl2 complex reveals that the tin is six-coordinate in a distorted octahedral geometry, where the two nitrogen atoms of homopiperazine and the two chloride ions are in one plane. The solid (Bu)2Sn(HP)Cl2 complex with homopiperazine was synthesized, and the composition was assigned by elemental micro-analysis and mass spectrum. The complex was investigated by infrared, mass spectra, and thermal measurements. The ligand and its complex were tested against antimicrobial Staphylococcus aureus (+ve), Escherichia coli (−ve), and antifungal Candida albicans and Aspergillus flavus. Anticancer activities of homopiperazine and its dibutyltin(IV) complex were tested against breast cancer cell lines. The molecular docking investigations were performed to know the possible modes of binding to the most active sites of the breast cancer oxidoreductase receptor and those of Escherichia coli. [ABSTRACT FROM AUTHOR]

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(MME)Cl2complex, where MME = methionine methyl ester, was synthesized and characterized by elemental analysis and spectroscopic techniques. [Pd(MME)(H2O)2]2+interacts with some DNA constituents giving 1 : 1 and 1 : 2 complexes. The binuclear complexes having 4,4′-bipiperidine as a linker and involving [Pd(MME)(H2O)2]2+and DNA constituents were investigated. The results show formation of [(H2O)(MME)Pd(Bip)Pd(MME)(H2O)]4+. Inosine, uracil, and thymine interact with the previously mentioned complex by substitution of the two coordinated water molecules. Formation constants of all possible mono- and binuclear complexes were determined and their speciation diagrams were evaluated. Electronic spectra of [Pd(MME) (H2O)2]2+and its uracil complexes Speciation of mono- and binuclear Pd(II) complexes involving mixed nitrogen–sulfur donor ligand is investigated; 4,4′-bipiperidine is used as a linker. [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]

The interaction of dimethyltin(IV) dichloride (DMT) with 1,4-piperazine (PIP) was investigated. The complex formation equilibria of the complexes formed in solution were investigated. The stoichiometry and stability constants of the complexes formed in solution phase were determined at different temperatures and in solutions of dioxane–water mixtures of different dielectric constants. The equilibrium constant for the displacement of piperazine coordinated to dimethyltin(IV) by inosine as a representative of DNA was calculated. (DMT)(PIP)·3H2O was synthesized and characterized by elemental analysis, spectral, and thermal techniques. The antitumor activity of the complex was screened. [ABSTRACT FROM PUBLISHER]

Abstract: 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 0.1M 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 &y& Elsevier]