Anticancer Activity and Apoptosis Induction of Gold(III) Complexes Containing 2,2'-Bipyridine-3,3'-dicarboxylic Acid and Dithiocarbamates.

Three novel gold(III) complexes (1-3) of general composition [Au(Bipydc)(S2CNR2)]Cl2 (Bipydc = 2,2'-bipyridine-3,3'-dicarboxylic acid and R = methyl for dimethyldithiocarbamate (DMDTC), ethyl for diethyldithiocarbamate (DEDTC), and benzyl for dibenzyldithiocarbamate (DBDTC)) have been synthesized and characterized by elemental analysis, FTIR and NMR spectroscopic techniques. The spectral results confirmed the presence of both the Bipydc and dithiocarbamate ligands in the complexes. The in vitro cytotoxic studies demonstrated that compounds 1-3 were highly cytotoxic to A549, HeLa, MDA-231, and MCF-7 cancer cells with activities much higher (about 25-fold) than cisplatin. In order to know the possible mode of cell death complex 2, [Au(Bipydc)(DEDTC)]Cl2 was further tested for induction of apoptosis towards the MCF-7 cells. The results indicated that complex 2 induces cell death through apoptosis.

Poly[[µ(3)-chlorido-bis(µ(2)-thio-urea-κS)disilver(I)] nitrate].

The mol-ecular structure of the title polymeric complex, {[Ag(2)Cl(CH(4)N(2)S)(2)]NO(3)}(n), consists of a binuclear cationic complex and a nitrate counter-ion. The cationic complex contains two bridging thio-urea (Tu) ligands and a triply bridging µ(3)-Cl anion. The latter is probably released from 2-amino-ethane-thiol hydro-chloride during the synthesis. The coordination environment around the two Ag(I) atoms is different; one is trigonal planar, being coordinated by two thio-urea ligands through the S atoms and to one Cl(-) ion, while in the other the Ag(I) atom is tetra-hedrally coordinated by two thio-urea ligands through the S atoms and to two Cl(-) ions. These units aggregate through the Cl(-) anion and the Tu S atoms, forming a chain propagating in [100]. In the crystal structure, the polymeric chains are linked via N-H⋯O and N-H⋯Cl hydrogen bonds, forming a double layer two-dimensional network propagating in (011).

Hexa-kis-(thio-urea-κS)nickel(II) nitrate: a redetermination.

A preliminary X-ray study of the title mol-ecular salt, [Ni(CH(4)N(2)S)(6)](NO(3))(2), has been reported twice previously, by Madar [Acta Cryst. (1961), 14, 894] and Rodriguez, Cubero, Vega, Morente & Vazquez [Acta Cryst. (1961), 14, 1101], using film methods. We confirm the previous studies, but to modern standards of precision and with all H atoms located. The central Ni atom (site symmetry ) of the dication is octa-hedrally coordinated by six S-bound thio-urea mol-ecules. The crystal structure is stabilized by intra- and inter-molecular N-H⋯S and N-H⋯O hydrogen bonds.

Adsorptive removal of acidic dye onto grafted chitosan: A plausible grafting and adsorption mechanism.

In the present research, a biopolymer Chitosan (C) grafted with ethylenediamine (EDA) and methyl acrylate (MA) were compared for the adsorption of Congo red dye from aqueous phase. The grafted chitosan product was characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and point of zero charge to study the change in mechanical and thermal properties. The effects of process variables like adsorbent loading, initial dye concentration, initial solution pH, contact time and temperature on adsorption phenomena were investigated. The equilibrium isotherm data was analyzed using Langmuir and Freundlich isotherm models, and the adsorption followed the Langmuir isotherm model (R2 = 0.992 and 0.991 for EDAC and MAC, respectively). The maximum adsorption capacity of EDAC and MAC for Congo red uptake calculated from Langmuir isotherm model was 1607 mg/g and 1143 mg/g, respectively. The adsorption kinetics was studied using pseudo 1st and 2nd order models. Pseudo second order rate model provided the best fit for both grafted adsorbents with R2 ≥0.99. The values of Gibbs free energy (-9.628 and -8.878 kJ/mol), enthalpy (44.9 and 42.2 kJ/mol) and entropy (0.18 and 0.17 J/mol·K) revealed spontaneous and endothermic adsorption of Congo red onto EDAC and MAC surface. The pollutant adsorption test indicated that chitosan grafting with ethylenediamine is superior to Methyl acrylate grafting agent.

Periodic DFT modeling and vibrational analysis of silver(I) cyanide complexes of thioureas.

The structures of non-ionic [Ag(Tu)(CN)] (1) and ionic [Ag(Dmtu)2]+[Ag(CN)2]- (2) and [Ag(Imt)2]+[Ag(CN)2]- (3) silver(I) complexes, where Tu = thiourea, Dmtu = N,N'-dimethylthiourea and Imt = imidazoline-2-thione), were modeled by periodic DFT/PAW-PBE calculations; results were in good agreement with experiments. The bonding ability of the thiourea ligands (Tu, Dmtu and Imt) and the rival Ag-C, Ag-S, Ag-N and Ag-Ag bonds were estimated by natural population analysis and natural bonding orbital calculations. The metal-ligand bond strengths were found to decrease in the following order Ag-CCN > Ag-Sthiourea > Ag-NCN, and the main bonding contribution was covalent, donor-acceptor and electrostatic, respectively. The non-ionic [Ag(Tu)(CN)] complex formation [distinguished from the ionic Ag(I) complexes] was explained with the largest bonding capacity of the sulfur donor atom of Tu ligand and the strongest covalent and donor-acceptor Ag-S(Tu) interaction. The infrared (IR) spectra of the experimentally observed structures were reliably interpreted and the IR vibrations, which were sensitive to the ligand coordination to Ag(I) ion and to the weak intra- and intermolecular interactions, were selected with the help of DFT frequency calculations in the solid state. Graphical abstract Non-ionic and ionic complex formation and the different coordination polyhedra around Ag(I) in three AgCN complexes of thioureas were evaluated by natural population analysis, natural bonding orbital, charge density and electron localization function calculations. The predicted largest capacity of sulfur (Tu) for donor-acceptor interaction, the largest bridging sulfur ability for three Ag ions and the strongest covalent and donor-acceptor Ag-S(Tu)3 interactions in 1 as compared to 2 and 3 explain the formation of a non-ionic complex, i.e., the Ag(CN)2- anion is missing in 1.

Bis[tris-(1,10-phenanthroline)nickel(II)] tris-[dicyanidoargentate(I)] nitrate 4.2-hydrate.

The title compound, [Ni(C(12)H(8)N(2))(3)](2)[Ag(CN)(2)](3)(NO(3))·4.2H(2)O, crystallizes with two independent [Ni(phen)(3)](2+) cations (phen is 1,10-phenanthroline; both Ni atoms have threefold symmetry and N(6) donor sets), three near-linear [Ag(CN)(2)](-) anions, one nitrate anion (N site symmetry 3) and 4.2 water mol-ecules of crystallization, some of which are disordered. The [Ag(CN)(2)](-) anions are situated within cavities created by the phenanthroline ligands of adjacent [Ni(phen)(3)](2+) cations. Some short C-H⋯O and C-H⋯N inter-actions may help to establish the packing.

New bipyridine gold(III) dithiocarbamate-containing complexes exerted a potent anticancer activity against cisplatin-resistant cancer cells independent of p53 status.

We synthesized, characterized and tested in a panel of cancer cell lines, nine new bipyridine gold(III) dithiocarbamate-containing complexes. In vitro studies demonstrated that compounds 1, 2, 4, 5, 7 and 8 were the most cytotoxic in prostate, breast, ovarian cancer cell lines and in Hodgkin lymphoma cells with IC50 values lower than the reference drug cisplatin. The most active compound 1 was more active than cisplatin in ovarian (A2780cis and 2780CP-16) and breast cancer cisplatin-resistant cells. Compound 1 determined an alteration of the cellular redox homeostasis leading to increased ROS levels, a decrease in the mitochondrial membrane potential, cytochrome-c release from the mitochondria and activation of caspases 9 and 3. The ROS scavenger NAC suppressed ROS generation and rescued cells from damage. Compound 1 resulted more active in tumor cells than in normal human Mesenchymal stromal cells. Gold compounds were active independent of p53 status: exerted cytotoxic effects on a panel of non-small cell lung cancer cell lines with different p53 status and in the ovarian A2780 model where the p53 was knocked out. In conclusion, these promising results strongly indicate the need for further preclinical evaluation to test the clinical potential of these new gold(III) complexes.

Copper complexes of bioactive ligands with superoxide dismutase activity.

Free radicals or reactive oxygen species (ROS) are highly toxic and their damaging effects result in a variety of detrimental health issues such as neurodegenerative, cardiovascular and age-related diseases. Human body has evolved an effective defense system including superoxide dismutase (SOD) and catalase against the toxicity of these free radicals. SOD is a metalloenzyme and it acts as an excellent antioxidant to protect the body from superoxide radicals that are generated in the biological system. However, the clinical use of SOD is limited due to its short in vivo life span, and its large size that hampered its penetration across the cell membranes. Pharmaceuticals that provide ROS scavenging systems are the most effective when the production of ROS exceeds the scavenging capacity of endogenous SOD as a result of aging or pathological processes. Inspired by the Nature, scientists have designed metal-based mimics of the superoxide dismutase. This review focuses on different copper complexes that are developed from bioactive ligands and mimic the protecting action of the SOD.