Search

Ruthenium(III) complexes are very promising candidates as metal-based anticancer drugs, and several studies have supported the likely role of human serum proteins in the transport and selective delivery of Ru(III)-based compounds to tumor cells. Herein, the anticancer nanosystem composed of an amphiphilic nucleolipid incorporating a Ru(III) complex, which we named DoHuRu, embedded into the biocompatible cationic lipid DOTAP, was investigated as to its interaction with two human serum proteins thought to be involved in the mechanism of action of Ru(III)-based anticancer drugs, i.e., human serum albumin (HSA) and human transferrin (hTf). This nanosystem was studied in comparison with the simple Ru(III) complex named AziRu, a low molecular weight metal complex previously designed as an analogue of NAMI-A, decorated with the same ruthenium ligands as DoHuRu but devoid of the nucleolipid scaffold and not inserted in liposomal formulations. For this study, different spectroscopic techniques, i.e., Fluorescence Spectroscopy and Circular Dichroism (CD), were exploited, showing that DoHuRu/DOTAP liposomes can interact with both serum proteins without affecting their secondary structures. [ABSTRACT FROM AUTHOR]

A series of amorphous RuS2 and SBA-15 supported RuS2 materials were prepared by solvothermal method using corresponding tris-dialkyldithiocarbamato ruthenium(III) complexes as precursors. The structures of the catalystline precursors Ru(S2CNR2)3 (R = Me, Et, iPr), unsupported and supported amorphous RuS2-R materials as well as nanocrystalline RuS2 were characterized and analyzed by IR, powder X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), transmission electron microscope (TEM), N2 sorption measurement, and temperature-programmed reduction (TPR). Powder X-ray diffraction patterns indicated the transformation of amorphous phase RuS2 to crystalline RuS2 with the heating treatment at 400 °C. The catalytic activity of RuS2-R/SBA-15 for thiophene hydrodesulfurization (HDS) was also investigated. [ABSTRACT FROM AUTHOR]

Ruthenium(III) complexes are very promising candidates as metal-based anticancer drugs, and several studies have supported the likely role of human serum proteins in the transport and selective delivery of Ru(III)-based compounds to tumor cells. Herein, the anticancer nanosystem composed of an amphiphilic nucleolipid incorporating a Ru(III) complex, which we named DoHuRu, embedded into the biocompatible cationic lipid DOTAP, was investigated as to its interaction with two human serum proteins thought to be involved in the mechanism of action of Ru(III)-based anticancer drugs, i.e., human serum albumin (HSA) and human transferrin (hTf). This nanosystem was studied in comparison with the simple Ru(III) complex named AziRu, a low molecular weight metal complex previously designed as an analogue of NAMI-A, decorated with the same ruthenium ligands as DoHuRu but devoid of the nucleolipid scaffold and not inserted in liposomal formulations. For this study, different spectroscopic techniques, i.e., Fluorescence Spectroscopy and Circular Dichroism (CD), were exploited, showing that DoHuRu/DOTAP liposomes can interact with both serum proteins without affecting their secondary structures.

This study is concerned with synthesis and characterization of four naphthaldiimine ligands and their ruthenium(III) complexes. The tetradentate diimines were synthesized by a Schiff condensation reaction between 2-hydroxy-1-naphthaldehyde and various aliphatic diamines with chains of 2, 4, 5 and 6 carbon atoms. Analytical, mass spectra, thermal and electrolytic solution conductance measurements demonstrated the molecular formulas of the prepared Ru(III) complexes. A distorted octahedron stereochemistry was proposed for these six-coordinate naphthaldiimine-based Ru(III) complexes. Processing of X-ray diffraction data of 1 and 2 by the computer program Expo 2014 confirmed the final structural formulas that were determined based on spectroscopic and magnetic studies. The catalytic potential of the newly synthesized naphthaldiimine-based Ru(III) complexes in the hydrogenation of 1-hexene and cyclohexene was investigated. The Ru(III) catalysts catalyzed the double bond migration of 1-hexene to give trans-2-hexene which catalytically isomerizes to the stereo isomer cis-2-hexene. The induction step of the catalytic cycle is the formation of the actual catalyst, metal hydride (Ru(III)-H), that was generated in situ during the hydrogenation reaction. Several parameters controlling the catalytic reactions including the structure of the Ru(III) complex, the phase type of catalysis, and the quantity and nature of the solvents used were investigated. Various experiments made it possible to suggest a mechanism for the hydrogenation reactions. [ABSTRACT FROM AUTHOR]

New series of mononuclear octahedral Ru(III) complexes of general formula [RuL1-3Cl]Cl2 (1-3) where L = dianion of Schiff bases namely: 2,2'-(((1E,1'E)-thiophene-2,5-diylbis(methaneylylidene))bis(azaneylylidene))diphenol (H2L1), 2,2'-(((1E,1'E)-thiophene-2,5-diylbis(methaneylylidene))bis(azaneylylidene))dibenzenethiol (H2L2) and 2,2'-(((1E,1'E)-thiophene-2,5-diylbis(methaneylyli-dene))bis(azaneylyli-dene))-dibenzoic acid (H2L3), respectively are synthesized and characterized by different physico-chemical techniques. The results of interaction of complexes with CT-DNA supported that, the Ru (III) complexes bind to DNA via an intercalative mode. The interaction has also been investigated by gel electrophoresis. Interestingly, it was found that all Ru(III) complexes cleave super coiled (SC) pUC19 plasmid DNA efficiently in the absence of an external agent. Further, the antiproliferative activity of the complexes on Human Cervical Cancer Cells (HeLa) and Human Breast Cancer Cells (MCF-7) were evaluated by MTT assay, which revealed that, all the complexes showed more intense inhibition against HeLa and MCF-7 cell lines, particularly Ru(III) complex (3) attenuated the strongest proliferation, allowing its use as chemotherapeutic agent for cancer treatment.

A number of reduced amino Schiff base ligands and corresponding ruthenium(III) complexes were designed and prepared based on the fact that amino acids not only possess multiple coordinate atoms but also improve the solubility of drugs in the body. The interaction of the complexes with calf thymus DNA was analyzed with spectroscopic methods of ultraviolet‐visible absorption spectra, DNA competitive binding with ethidium bromide, circular dichroism spectra, and DNA melting experiments, and DNA viscosity measurements, indicating that the complexes bind to DNA primarily in the grooving mode. With respect to the ligands, the cytotoxicity in vitro of the complexes against Hela, A549, and MCF‐7 cells was much enhanced, with most of the IC50 values less than 50 μM or even comparable with those of cisplatin. [ABSTRACT FROM AUTHOR]

Abstract: The structural difference between five sulfa drug compounds and their Ru(III) complexes with 1 : 2 molar ratio were examined using the positron annihilation Doppler broadening (PADB) spectroscopy. The PADB measurements were performed with a HPGe γ-ray spectrometer. The change of defect structure due to the Ru(III) complexation process was confirmed. The correlation between the DP line-shape parameters (S and W) and the previous reported results of the microanalytical, physicochemical, biological and positron annihilation lifetime (PAL) measurements of sulfa drug Ru(III) complexes were examined. [ABSTRACT FROM AUTHOR]

A new class of ruthenium(III) complexes containing O, N donor functionalized azo derivatives were designed and synthesized. The synthesized compounds were characterized by fourier‐transform infrared (FTIR), ultraviolet–visible (UV‐vis) and electron paramagnetic resonance (EPR) spectral studies. The X−ray crystal structure of one of the complexes [Ru(L1)3] 1 has been determined. The catalytic activity of the complex [Ru(L1)3] 1 has been studied for the oxidation of primary and secondary alcohols to corresponding carbonyl compounds in the presence of N‐ Methylmorpholine‐N‐Oxide as co‐oxidant. A new class of ruthenium(III) complexes containing O, N donor functionalized azo derivatives were designed and synthesized. The X−ray crystal structure of one of the complexes [Ru(L1)3] 1 has been determined. The catalytic activity of the complex [Ru(L1)3] 1 has been studied for the oxidation of primary and secondary alcohols to corresponding carbonyl compounds in the presence of NMO as co‐oxidant. [ABSTRACT FROM AUTHOR]

Graphical abstract In all substitution kinetics reactions, a single step, considered to be the displacement of the coordinated chlorides was seen with no solvation pathway. Due to the symmetrical nature of the investigated ruthenium(III) complexes, the three chloride ligands are equally substituted simultaneously. The docking experiments reveal that the binding energies of the complexes have direct correlation to their kinetic stability. Highlights • Ruthenium(III) complexes were successfully synthesised. • The substitution of the coordinated chloro ligands happened simultaneously. • Density functional theoretical calculations supports substitution kinetic results. • Complexes demonstrate low antineoplastic properties against Hela cancer cells. • Molecular docking of the compounds demonstrate good affinity for DNA molecule. Abstract The present work investigates the kinetics of ligand substitution reaction and anticancer activities of the complexes, [{2-(2-pyridyl) benzimidazole} RuCl 3 ] (C1), [{2-(2-pyridyl) benzoxazole} RuCl 3 ] (C2), [{2-(2-pyridyl) benzothiazole} RuCl 3 ] (C3) and [{1-propyl-2- (pyridin-2-yl)-H-benzoimidazole} RuCl 3 ] (C4). The substitution kinetics reaction of the complexes with the three bio-relevant nucleophiles, viz.: thiourea (TU), 1, 3-dimethyl-2-thiourea (DMTU) and 1, 1, 3, 3-tetramethyl-2-thiourea (TMTU) was investigated under pseudo first-order conditions as a function of concentration and temperature using UV–Visible spectrophotometer. The substitution of the coordinated chloride was controlled by the electronic effect. The order of reactivity of the complexes with the nucleophiles is in the form C1 > C2 > C3 > C4 which is in line with the density functional theory (DFT) studies. The complexes showed minimal anticancer activity against the HeLa cell line, which is in contrast to the molecular docking experiments that exhibited stronger DNA binding affinities. [ABSTRACT FROM AUTHOR]

This study evaluates the genotoxic potential of two Ru(III) complexes with thiosemicarbazone based ligands. The complexes were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using the cytokinesis block micronucleus (CBMN) assay at concentrations 1.5; 3.7 and 7.4 μg/mL. The cell culture treated with the tested complexes, at 3.7 μg/mL concentration, decreased a frequency of micronucleus for 37% and 32%, when compared with the control cell cultures. At concentration of 7.4 (1.5) μg/mL of this complexes exhibited slightly lower effect of micronucleus for 30% (35%) and 27% (29%), when compared with the control cell cultures. [ABSTRACT FROM AUTHOR]

In our search for new anticancer and DNA interacting agents, ruthenium(III) thiosemicarbazone complexes of the type [RuCl2(EPh3)L] (where E = P/As; L = monobasic tridentate thiosemicarbazone ligand) were synthesized and characterized by physico-chemical and spectroscopic methods. All the ligands and complexes exhibit noticeable growth inhibition against fungal species and bacterial species. The interactions of these complexes with biomolecule, CT-DNA were investigated by absorbance measurement and gel electrophoresis. Absorption spectral study indicates that the ruthenium(III) complexes have an intrinsic binding constant in the range of 1.0–3.6 × 104 M−1. The complexes exhibit a remarkable DNA cleavage activity with CT-DNA in the presence of hydroxyl radical. The cleavage activity was carried out with the variation of the concentration of complexes and incubation time. Further, an in vitro cytotoxicity study of the complexes exhibited antitumor activity against the HeLa tumor cell line. This research may provide valuable insight into the interactions of metal complexes with DNA and cytotoxicity, knowledge that is an excellent back drop for the rational design of promising drugs.

The great advances in the studies on metal complexes for the treatment of different cancer forms, starting from the pioneering works on platinum derivatives, have fostered an increasingly growing interest in their properties and biomedical applications. Among the various metal-containing drugs investigated thus far, ruthenium(III) complexes have emerged for their selective cytotoxic activity in vitro and promising anticancer properties in vivo, also leading to a few candidates in advanced clinical trials. Aiming at addressing the solubility, stability and cellular uptake issues of low molecular weight Ru(III)-based compounds, some research groups have proposed the development of suitable drug delivery systems (e.g., taking advantage of nanoparticles, liposomes, etc.) able to enhance their activity compared to the naked drugs. This review highlights the unique role of Ru(III) complexes in the current panorama of anticancer agents, with particular emphasis on Ru-containing nanoformulations based on the incorporation of the Ru(III) complexes into suitable nanocarriers in order to enhance their bioavailability and pharmacokinetic properties. Preclinical evaluation of these nanoaggregates is discussed with a special focus on the investigation of their mechanism of action at a molecular level, highlighting their pharmacological potential in tumour disease models and value for biomedical applications.

Ruthenium(III) complexes of the type [RuX2(PPh3)(L)] (where X = Cl/Br; L = Benzothiazolyl-Salal Schiff base ligand) has been synthesized. The synthesized complexes were characterized by various physicochemical and spectral techniques. An octahedral geometry has been tentatively proposed for all the complexes. The cytotoxic activity of the synthesized ruthenium(III) complexes has shown significant activity against a panel of microbes. [ABSTRACT FROM AUTHOR]

The ruthenium complex sodium trans -[tetrachloridobis(1 H -indazole)ruthenate(III)] (KP-1339/IT139) has entered clinical trials as the more soluble alternative to the indazolium compound KP1019. In order to get insight into its distribution and accumulation throughout a living organism, KP-1339/IT139 was administered intravenously in non-tumor bearing nude BALB/c mice and the Ru content in blood cells and plasma, bone, brain, colon, kidneys, liver, lung, muscle, spleen, stomach and thymus was determined at several time points. The Ru concentration in blood cells and plasma was found to increase slightly within the first hours of analysis, with the Ru concentration being 3-times higher in plasma compared to blood cells. The plasma samples were subjected to analysis by capillary zone electrophoresis (CZE) and size exclusion/anion exchange chromatography (SEC-IC) both coupled to inductively coupled plasma-mass spectrometry (ICP-MS) and a large majority of the total Ru content was found attached to mouse serum albumin (MSA), confirming similar behavior to KP1019 in an in vivo setting. Within 1 h, the peak ratio of approximately 1.2–1.5 Ru per albumin molecule was reached which declined to about 1 Ru per albumin molecule within 24 h. Beside the MSA adduct a higher molecular weight species was observed probably stemming from MSA conjugates. In addition, the tissue samples were mineralized by microwave digestion and analyzed for their Ru content. The highest Ru levels were found in colon, lung, liver, kidney and notably in the thymus. The peak Ru concentrations in these tissues were reached 1–6 h after administration and declined slowly over time. [ABSTRACT FROM AUTHOR]

In this work, five ruthenium(III) complexes containing phosphine and pyridine based ligands with general formula mer -[RuCl 3 (dppb)(N)] [where dppb = 1,4-bis(diphenylphosphino)butane and N = pyridine (py), 4-methylpyridine (4-Mepy), 4-vinylpyridine (4-Vpy), 4- tert -butylpyridine (4- t Bupy) and 4-phenylpyridine (4-Phpy)] were synthesized and characterized using spectroscopic and electrochemical techniques, as well as magnetic susceptibility to check the paramagnetism of these compounds. These complexes were tested as catalytic precursors in hydrogenation reactions with cyclohexene, undecanal and cyclohexanecarboxaldehyde, as compounds bearing C C and C O groups. Broad screening was carried out in order to find the optimal reaction conditions with the highest conversion. It was found that by using a ratio of Ru-catalyst/substrate = 1:530 at 80 °C and 15 bar of H 2 for 24 h, cyclohexene can be reduced. Hydrogenation of undecanal was possible using a Ru-catalyst/substrate ratio of 1:100 at 160 °C and 100 bar for 24 h, and for the reduction of cyclohexanecarboxaldehyde the reaction conditions were Ru-catalyst/substrate ratio of 1:100 at 160 °C and 50 bar for 24 h. [ABSTRACT FROM AUTHOR]

Ruthenium(III) complexes of cystamine-based disulfide ligands with the general formula [RuXL] (X = Cl or Br; L = pentadentate Schiff base ligands) were synthesized from ruthenium precursor complexes [RuX(AsPh)] (X = Cl or Br) and disulfide ligands derived from cystamine and 2-hydroxy-substituted aromatic aldehydes, viz., salicylaldehyde, 5-chlorosalicylaldehyde, o-vanillin, and 2-hydroxynaphthaldehyde for L-L, respectively. The ligands and their complexes were structurally characterized by elemental, spectral (UV-Vis, IR, NMR, EPR, and ESI-mass) and cyclic voltammetry methods. The new complexes have shown effective hydrogen transfer properties, which were studied in the catalytic transfer hydrogenation of some secondary alcohols using gas chromatography. The catalytic properties of the complexes toward the N-alkylation of o-substituted anilines were analyzed in detail showing that this catalytic reaction involved two important hydrogen transfer steps. Hence, a new suitable and efficient catalytic system has been investigated for the synthesis of various benzazoles in a one-pot reaction. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This paper describes the synthesis of two sulfonamides (NethylS and NpropylS) differing in the length of the alkylamino substituent. Their physicochemical characteristics are discussed, with particular emphasis on the electrochemical profile, acid-base character, and complexing ability towards trivalent rhodium and ruthenium ions. [Display omitted] Two sulfonamide derivatives differing in the length of alkylamino substituent (NethylS and NpropylS) had been synthesized and then their structure and physicochemical properties were the subject of our extensive research. The complete spectroscopic and electrochemical profiles of studied compounds together with their ionic species assignment were established as well as reported. The electrochemical characteristics of sulfonamides were examined in both aqueous and aprotic solvents using cyclic voltammetry (CV) and differential pulse voltammetry technique (DPV). Furthermore, the pH effect on the NethylS/NpropylS redox processes and spectroscopic properties were also studied. The p K a values of compounds were determined using the combined pH-spectrophotometric (micro)titration method. The activity of studied sulfonamide antibiotics was verified by binding them into complexes with d-block metal ions, for which the complexing properties of both NethylS and NpropylS towards ruthenium(III) and rhodium(III) ions as well as their corresponding stability constants were determined. [ABSTRACT FROM AUTHOR]

The reactions of benzothiazolyl thiosemicarbazone with [RuX3(PPh3)3] (X = Cl/Br) in a 1:1 molar ratio have given stable solid complexes corresponding to the general formula [RuX(PPh3)2(L)]. Structural features were determined by analytical and spectral techniques. DNA binding properties of the ligands and its ruthenium(III) complexes have been investigated by electronic absorption spectroscopy. The complexes show good binding affinity to calf-thymus DNA. Gel electrophories of pBR322 DNA with complexes demonstrated that the complexes exhibit excellent cleavage activityviaoxidative pathway. In addition, the antioxidant activity of the free ligands and its complexes was determined by DPPH and hydroxyl radicals. The complexes were found to possess potent antioxidant activity. [ABSTRACT FROM PUBLISHER]

Highlights: [•] New cis and trans Ru(III) complexes with NSNO donor azo thioether ligand. [•] Pseudo octahedral geometry of cis complex has been confirmed by X-ray structure. [•] DFT calculation has been used to predict the electronic structure of the complexes. [•] The electronic spectra have been interpreted by TDDFT calculation. [•] Ru(III) complexes catalyze oxidation of alcohols to carbonyl compounds with NMO. [ABSTRACT FROM AUTHOR]

The synthesis, characterization, and biological studies of ruthenium(III) complexes containing ONS/ONO tridentate ligands are reported. Reactions of 1,2-naphthoquinone N-substituted thiosemicarbazone/semicarbazone (HL n; n = 1–4) with [RuCl 3(EPh 3) 3] (E = P or As) gave [RuCl 2(EPh 3)(L n)], which were characterized by elemental analysis, FT-IR, UV–Vis, magnetic susceptibility measurement, ESR spectra, ESI–MS, electrochemical studies, and powder X-ray diffraction pattern. The free radical scavenging ability, assessed by antioxidant assays involving DPPH and hydroxyl radicals, showed that the complexes possess excellent radical scavenging properties. The in vitro cytotoxicity of the complexes against MCF-7 and A431 cell lines was assayed which showed that the ruthenium(III) complexes exhibited effective cytotoxic activity against selected cancer cells. Furthermore, the complexes were found to promote the cleavage of plasmid pBR322 DNA. Graphical abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] Molecular structure of ligands was elucidated by X-ray diffraction study. [•] The ligands and complexes interact with CT-DNA, intercalatively. [•] The complexes can efficiently cleave CT-DNA via oxidative cleavage. [•] The complexes possess significant antioxidative property against DPPH radical. [•] The complex 3 shows higher IC50 value than the other complexes against tumor cells. [ABSTRACT FROM AUTHOR]

Speciations of ruthenium(III)-edta complexes of bidentate (O, O) (N, O) and (S, O) donor type ligands were determined by pH-potentiometry and UV/Vis spectrophotometry in aqueous solution. Complexes of [RuIII(edtaH x)L]2- ( x = 0, 1, 2 and 3) stoichiometry were only formed and the fully deprotonated species dominate at the physiological pH 7.4. Protonation occurs at the free carboxylate arms of edta; when x = 3 one of the coordination positions of the RuIII becomes free. Formation of protonated ternary complexes are more characteristic for ligands with (N, O) and (S, O) donor sets where the complex formation started (ligands with (N, O) donor set) or completed (ligands with (S, O) donor set) already at pH 2. In acidic conditions the stability order of the complexes follows the (O, O) < (N, O) < (S, O) sequence, which changes slightly for the physiological pH 7.4: (O, O) ≈ (N, O) < (S, O). The complexes formed were characterised also by LNT EPR spectroscopy. The kinetics of the ligand exchange between ternary complexes at pH 6 was found to be dissociative. The reaction rate follows basically the stability order: (O, O) < (N, O) < (S, O). No side reactions were found when the ligands replaced had (O, O) donor set; but formation of [RuIII(edta)(L1),(L2)]3- was hypothesised in the case of ligands with (N, O) or (S, O) donor sets. [ABSTRACT FROM AUTHOR]

A new Schiff base, 3-(benzothiazol-2-yliminomethyl)-naphthalen-2-ol, has been synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy (FT-IR), UV–vis, nuclear magnetic resonance, and single-crystal X-ray diffraction. Ruthenium(III) complexes of the Schiff base were synthesized and characterized by analytical and spectroscopic (FT-IR, UV–vis, and electron paramagnetic resonance) data as well as magnetic susceptibility measurements. DNA-binding properties of the ligand and its ruthenium(III) complexes have been investigated by electronic absorption spectroscopy. The three ruthenium(III) complexes were tested for DNA cleavage. Furtherin vitrostudy of the cytotoxity of the ligand and the complexes on human cervical cancer cell line and human laryngeal epithelial carcinoma cell line were carried out. [ABSTRACT FROM AUTHOR]

Lipid-conjugated Ru(III) complexes - designed to obtain lipophilic analogues of the low molecular weight derivative AziRu, which is a NAMI-A-like anticancer agent - have been synthesized and fully characterized. A detailed biophysical investigation, including multiple, integrated techniques, allowed determining their molecular and self-assembling properties in aqueous solutions mimicking the extracellular environment, showing that our design produced a protective effect from hydrolysis of the Ru(III) complexes. In vitro biological experiments, carried out in comparison with AziRu, demonstrated that, among the novel lipophilic Ru(III) complexes synthesized, the compounds derivatized with palmitic and stearic acid, that we named PalmiPyRu and StePyRu respectively, showed attractive features and a promising antiproliferative activity, selective on specific breast cancer phenotypes. To get a deeper insight into their interactions with potential biomacromolecular targets, their ability to bind both bovine serum albumin (BSA), an abundant serum carrier protein, and some DNA model systems, including duplex and G-quadruplex structures, has been investigated by spectroscopic techniques. Inductively coupled plasma-mass spectrometry (ICP-MS) analysis of the ruthenium amount incorporated in human MCF-7 and MDA-MB-231 breast cancer cells, after incubation in parallel experiments with PalmiPyRu and AziRu, showed a markedly higher cell uptake of the lipophilic Ru(III) complex with respect to AziRu. These data confirmed that the proper lipidic tail decorating the metal complex not only favoured the formation of aggregates in the extracellular media but also improved their cell membrane penetration, thus leading to higher antiproliferative activity selective on breast cancer cells., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Binuclear ruthenium(III) complexes [RuX3L]2 · nH2O (X = Cl, L = L1, L2, L3; n = 1, L4 and L5, X = Br; L = L3), [RuX3L1.5]2 · nH2O (X = Br, L = L1; n = 0, L4; n = 6 and L5; n = 10), and [RuX3L2]2 (X = Br, L = L2) have been isolated by treatment of hydrated RuX3 (X = Cl/Br) in acetone with 2-(2′-aminophenylbenzimidazole) (L1), 2-(3′-aminophenylbenzimidazole) (L2), 2-[(3′-N-salicylidinephenyl)benzimidazole] (L3), 2-(3′-pyridylbenzimidazole) (L4), and 2-(4′-pyridylbenzimidazole) (L5) in acetone. The complexes were characterized by elemental analysis, conductivity and magnetic susceptibility measurements, IR, electronic, EPR, and mass spectral studies. The complexes were dimeric; based on analytical and spectral studies, an octahedral geometry was proposed for the complexes. The synthesized complexes were screened against Gram-positive and Gram-negative bacteria and fungi. [ABSTRACT FROM PUBLISHER]

Abstract: Reactions of 2-acetylpyridine-thiosemicarbazone HL1, 2-acetylpyridine-4-methyl-thiosemicarbazone HL2, 2-acetylpyridine-4-phenyl-thiosemicarbazone HL3 and 2-acetylpyridine-semicarbazone HL4 with ruthenium(III) precursor complexes were studied and the products were characterized by analytical and spectral (FT-IR, electronic, EPR and EI-MS) methods. The ligands coordinated with the ruthenium(III) ion via pyridine nitrogen, azomethine nitrogen and thiolate sulfur/enolate oxygen. An octahedral geometry has been proposed for all the complexes based on the studies. All the complexes are redox active and display an irreversible and quasireversible metal centered redox processes. Further, the catalytic activity of the new complexes has been investigated for the transfer hydrogenation of ketones in the presence of isopropanol/KOH and the Kumada–Corriu coupling of aryl halides with aryl Grignard reagents. The DNA cleavage efficiency of new complexes has also been tested. [Copyright &y& Elsevier]

New copper and ruthenium mononuclear complexes of the type [ML2(H2O)X] [X = H2O for M = Cu(II) and X = Cl for M = Ru(III)] have been prepared from 1-p-diphenyl- methane-2-hydroxyimino-2-(4-chloroanilino)-1-ethanone (HL1) and 1-p-diphenylmethane-2-hydroxyimino-2-(4-toluidino)-1-etha- none (HL2). The complexes were characterized by elemental analyses, magnetic susceptibility, molar conductance, IR, thermal analysis, and cyclic voltammetry. Stoichiometric and spectral results of the metal complexes indicated that the metal:ligand ratios in the complexes were found to be 1:2 and the ligands behave as a bidentate ligand forming neutral metal chelates through the carbonyl and oxime oxygen. The electrochemical behavior of the ligands and their complexes were obtained by cyclic voltammetry. The interaction between these complexes with DNA has also been investigated by agarose gel electrophoresis. The copper(II) complexes (3 and 4) with H2O2 as a co-oxidant exhibited strongest cleaving activity. Moreover, catalytic activities of the complexes for the disproportionation of hydrogen peroxide were also investigated in the presence of imidazole. [ABSTRACT FROM PUBLISHER]

Abstract: The ruthenium(III) complexes [Ru(L n )2]ClO4 with 4-R-2-((2-(pyridin-2-yl)hydrazono)methyl)phenol (HL n ; R =H, Cl, Br, Me and OMe) have been synthesized. Microanalysis, magnetic susceptibility and various spectroscopic (IR, UV–Vis and EPR) measurements have been used for the characterization of these complexes. The molecular structures of all the complexes, except for the complex where R =Br, have been confirmed by a single crystal X-ray diffraction study. The metal centers in these complex cations are in a distorted octahedral N4O2 environment formed by the pyridine-N, the imine-N and the phenolate-O donor (L n )− ligands. Intermolecular hydrogen-bonding assisted supramolecular structures assembled by the solvated complexes range from dimeric to one-dimensional chain to two-dimensional sheet structures. [Copyright &y& Elsevier]

Abstract: Two novel rhenium(IV)–ruthenium(III) compounds of formulae [RuCl(NH3)5]2[ReCl6]Cl2 (1) and [RuCl2(en)2]2[ReCl6]·2CH3CN (2) (en=1,2-ethylenediamine) have been prepared and characterized. Their crystal structures were determined by single-crystal X-ray diffraction. 1 crystallizes in the monoclinic system with C2/m as space group, whereas 2 crystallizes in the triclinic system with space group P(−1). The crystal structures of 1 and 2 are made up of discrete [ReCl6]2− anions and [RuCl(NH3)5]2+ (1) or [RuCl2(en)2]+ (2) cations held together by N–H···Cl hydrogen bonds, van der Waals and electrostatic forces. The magnetic properties were investigated from susceptibility measurements performed on polycrystalline samples of 1 and 2 in the temperature range 1.9–300K. In both compounds, the variation of χ M T in the high-temperature range reveals an antiferromagnetic coupling whereas they exhibit behaviour typical of spin-canted systems with magnetic ordering below ca. 11.0 (1) and ca. 4.5K (2). [Copyright &y& Elsevier]

Abstract: A series of novel octahedral ruthenium(III) complexes involving 6-benzylaminopurine (L) derivatives as N-donor ligands has been prepared by the reaction of [(DMSO)2H][trans-RuCl4(DMSO)2] with the corresponding L derivative. The complexes 1–12 have the general compositions trans-[RuCl4(DMSO)(n-Cl-LH)]⋅ xSol (1–3), trans-[RuCl4(DMSO)(n-Br-LH)]· xSol (4–6), trans-[RuCl4(DMSO)(n-OMe-LH)]· xSol (7–9) and trans-[RuCl4(DMSO)(n-OH-LH)]· xSol (10–12); n=2, 3, and 4, x =0–1.5; and Sol = H2O, DMSO, EtOH and/or (Me)2CO. The complexes have been thoroughly characterized by elemental analysis, UV–visible, FTIR, Raman, and EPR spectroscopy, ES+(positive ionization electrospray) mass spectrometry, thermal analysis, cyclic voltammetry, magnetic and conductivity measurements. The X-ray molecular structure of trans-[RuCl4(DMSO)(3-Br-LH)]⋅(Me)2CO (5) revealed the distorted octahedral coordination in the vicinity of the central atom, and also confirmed that the 3-Br-L ligand is present as the N3-protonated N7-H tautomer and is coordinated to Ru(III) through the N9 atom of the purine moiety. The tested complexes have been found to be in vitro non-cytotoxic against K562, G361, HOS and MCF7 human cancer cell lines with IC50 >100μM in contrast to the moderate results regarding the antiradical activity with IC50 ≈10−3 M. On the contrary, in vivo antitumor activity screening showed that the prepared Ru(III) complexes possess higher pro-apoptotic activity than NAMI-A. The reduction of Ru(III) to Ru(II) and Ru(II)-species formation in tumor tissues was confirmed by means of a simple method of detection and visualization of intracellular Ru(II) by fluorescence microscopy. The originality of this method is based on the preparation of a Ru(II)-bipyridine complex in situ. [Copyright &y& Elsevier]

Abstract: New hexa-coordinated Ru(III) complexes of the type [Ru(H2Pzdc)(EPh3)3X2] have been synthesized by reacting 3,5-pyrazole dicarboxylic acid (H3Pzdc) with the appropriate starting complexes [RuX3(EPh3)3] (where X=Cl or Br; E=P or As). The ligand behaves as a bidentate monobasic chelate. All the complexes have been characterized by analytical and spectroscopic (IR, electronic and EPR) data. Single-crystal X-ray analysis of the complex [Ru(H2Pzdc)(PPh3)2Cl2]·C6H6·C2H5OH revealed that the coordination environment around the ruthenium center consists of an NOP2Cl2 octahedron. The planar ligand occupies the equatorial position along with two chlorine atoms, while the triphenylphosphine groups occupy the axial positions. The electrochemical behavior of the new complexes was studied using cyclic voltammetry. The new mononuclear ruthenium complexes are capable of acting as catalysts for the oxidation of alcohols. [Copyright &y& Elsevier]

Ruthenium(III) complexes of the type [RuX(EPh3)(L)2] (X = Cl or Br; E = P or As; L = 2-hydroxychalcone) have been prepared by reacting [RuX3(EPh3)3] with 2-hydroxychalcones in benzene under reflux. The new complexes have been characterized by analytical and spectroscopic (infrared, electronic, electron paramagnetic resonance, and mass) methods. Redox potential studies of the complexes have been carried out to elucidate the electronic structure, geometry, and electrochemical features. On the basis of data obtained, an octahedral structure has been assigned for all the complexes. The new complexes exhibit catalytic activity for the oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine-N-oxide as co-oxidant and they were also found to be efficient catalyst for the transfer hydrogenation of ketones. [ABSTRACT FROM AUTHOR]

The reactions of [RuX3(EPh3)3] (X = Cl or Br; E = P or As) with 2'-hydroxychalcones in benzene under reflux led to the formation of [RuX2(EPh3)2(L)] (X = Cl or Br; E = P or As; L = chalconates). The new complexes have been characterized by analytical and spectroscopic (IR, electronic, and EPR) data. The redox behavior of the complexes has also been studied. Based on the data, an octahedral structure has been assigned for all the complexes. The new complexes exhibit efficient catalytic activity for the oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine-N-oxide (NMO) as co-oxidant and also found efficient catalytic activity for the transfer hydrogenation of ketones. The antifungal properties of the complexes have also been examined and compared with standard Bavistin. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. [ABSTRACT FROM AUTHOR]

Abstract: Mononuclear ruthenium(III) complexes of the type [RuX(EPh3)2(L)] (E=P or As; X=Cl or Br; L=dibasic terdentate dehydroacetic acid thiosemicarbazones) have been synthesized from the reaction of thiosemicarbazone ligands with ruthenium(III) precursors, [RuX3(EPh3)3] (where E=P, X=Cl; E=As, X=Cl or Br) and [RuBr3(PPh3)2(CH3OH)] in benzene. The compositions of the complexes have been established by elemental analysis, magnetic susceptibility measurement, FT-IR, UV–vis and EPR spectral data. These complexes are paramagnetic and show intense d–d and charge transfer transitions in dichloromethane. The complexes show rhombic EPR spectra at LNT which are typical of low-spin distorted octahedral ruthenium(III) species. All the complexes are redox active and display an irreversible metal centered redox processes. Complex [RuCl(PPh3)2(DHA–PTSC)] (5) was used as catalyst for transfer hydrogenation of ketones in the presence of isopropanol/KOH and was found to be the active species. [Copyright &y& Elsevier]

New six-coordinate ruthenium(III) complexes [RuX(EPh3)2(L)] (X = Cl or Br; E = P or As; L = chalcone thiosemicarbazone) have been prepared by reacting [RuX3(EPh3)3] (X = Cl or Br; E = P or As) with chalcone thiosemicarbazones in benzene under reflux. The new complexes have been characterized by analytical and spectroscopic (IR, electronic, mass, and EPR) data. The redox behavior of the complexes has also been studied. Based on the above data, an octahedral structure has been assigned for all the complexes. The new complexes exhibit catalytic activity for carbon-carbon coupling reactions. [ABSTRACT FROM AUTHOR]

Abstract: [RuCl3 · nH2O] and Na(trans-[RuCl4(DMSO)2]) were reacted with 1-pyrrolidinedithiocarbamate (PDT), its S-methyl ester (PDTM), and N,N-dimethylcarbamodithioic acid methyl ester (DMDTM) in water or methanol in order to obtain the corresponding Ru(III) derivatives. Once isolated and purified, the complexes were characterized by means of elemental analysis, conductivity measurements, FT-IR and 1H NMR spectroscopy, ion electrospray mass spectrometry (ESI-MS), and thermal analyses. The crystal structure of mer-[Ru(DMDTM)(DMSO)Cl3] has been also determined by X-ray crystallography. In vitro cytotoxic activity of all the synthesized complexes was eventually evaluated on some selected human tumor cell lines. [Copyright &y& Elsevier]

Abstract: A redox active self-assembled monolayer consisting of ethylenediamine moieties coordinated to RuIII ions was prepared through a vapor phase silane coupling of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AEAPS) molecules onto a SiO2/Si substrate, followed by complexation of RuIII ions in an aqueous RuCl3 solution. A similar SAM with 3-aminopropyltriethoxysilane did not provide surface RuIII-complex, indicating that chelation ability plays a key role in immobilizing RuIII ions at the surface. The RuIII chelated AEAPS-SAM gave a couple of RuIII/RuIV redox peaks at +1.0 and −0.1V vs. Ag/AgCl (3moldm−3 NaCl). [Copyright &y& Elsevier]

Abstract: The reactions of 1molequiv. each of [Ru(PPh3)3Cl2] and N-(acetyl)-N′-(5-R-salicylidene)hydrazines (H2ahsR, R=H, OCH3, Cl, Br and NO2) in alcoholic media afford simultaneously two types of complexes having the general formulae [Ru(HahsR)(PPh3)2Cl2] and [Ru(ahsR)(PPh3)2Cl]. The complexes have been characterized by elemental analysis, magnetic, spectroscopic and electrochemical measurements. Molecular structures of [Ru(HahsH)(PPh3)2Cl2] and [Ru(ahsH)(PPh3)2Cl] have been confirmed by X-ray crystallography. In both species, the PPh3 ligands are trans to each other. The bidentate HahsH− coordinates to the metal ion via the O atom of the deprotonated amide and the imine–N atom in [Ru(HahsH)(PPh3)2Cl2]. In HahsH−, the phenolic OH is involved in a strong intramolecular hydrogen bond with the uncoordinated amide N atom forming a seven-membered ring. In [Ru(ahsH)(PPh3)2Cl], the tridentate ahsH2− binds to the metal ion via the deprotonated amide O, the imine N and the phenolate O atoms. In the electronic spectra, the green [Ru(HahsR)(PPh3)2Cl2] and brown [Ru(ahsR)(PPh3)2Cl] complexes display several absorptions in the ranges 385–283 and 457–269nm, respectively. Both complexes are low-spin and display rhombic EPR spectra in frozen solutions. Both types of complexes are redox active and display a quasi-reversible ruthenium(III) to ruthenium(II) reduction which is sensitive to the polar effect of the substituent on the chelating ligand. The reduction potentials are in the ranges −0.21 to −0.12 and −0.42 to −0.21V (versus Ag/AgCl) for [Ru(HahsR)(PPh3)2Cl2] and [Ru(ahsR)(PPh3)2Cl], respectively. [Copyright &y& Elsevier]

Abstract: New hexa-coordinated ruthenium(III) complexes of the type [RuX2(EPh3)2(L)] (E=P or As; X=Cl or Br; L=monobasic bidentate Schiff base derived from the condensation of benzhydrazide with furfuraldehyde, 2-acetylfuran and 2-acetylthiophene) have been synthesized from the equimolar amounts of [RuX3(EPh3)3] or [RuBr3(PPh3)2(MeOH)] and Schiff bases in benzene. The new complexes have been characterized by analytical, spectral (IR, electronic and EPR), magnetic moment, and cyclic voltammetry. An octahedral structure has been tentatively proposed. All the complexes have exhibited catalytic activity for the oxidation of benzyl alcohol, cyclohexanol and cinnamylalcohol in the presence of N-methylmorpholine-N-oxide as co-oxidant. All the new complexes were found to be active against the bacteria such as E. coli, Pseudomonas, Salmonella typhi and Staphylococcus aureus. The activity was compared with standard Streptomycin. [Copyright &y& Elsevier]

Abstract: The use of the mononuclear complex trans-[Ru(acac)2(CN)2]− as a ligand towards the preformed species [Ni2L(H2O)2Cl2], [Co(dmphen)](NO3)2, [Ni(dmphen)](NO3)2 and [Co(H2O)6](NO3)2 afforded the novel cyanide-bridged bimetallic compounds of formula [{Ru(acac)2(CN)2}{Ni2(L)(H2O)2}]{Ru(acac)2(CN)2}·2H2O (1), [{Ru(acac)2(CN)2}{Co(dmphen)(NO3)}]·H2O (2) and [{Ru(acac)2(CN)2}{Ni(dmphen)(NO3)}]·H2O (3) and [{Ru(acac)2(CN)2}2Co] (4) [Hacac=acetylacetone, dmphen=2,9-dimethylphenanthroline and H2L=11,23-dimethyl-3,7,15,19-tetrazatricyclo[19.3.1.19,13]hexacosa-2,7,9,11,13(26),14,19,21(25),22,24-decaene-25,26-diol]. Their syntheses, X-ray crystal structures and magnetic properties are reported here. The structure of 1 consists of cationic cyanide-bridged chains of formula [{Ru(acac)2(CN)2}{Ni2(L)(H2O)2}]+ and mononuclear anions [Ru(acac)2(CN)2]−. Compounds 2 and 3, which are isostructural, are made up of cyanide-bridged neutral chains [{Ru(acac)2(CN)2}{M(dmphen)(NO3)}] with regular alternating ruthenium(III) and cobalt(II) (2)/nickel(II) (3) ions. Each cobalt atom in 4 is tetrahedrally coordinated by four [RuIII(acac)2(CN)2]− ions through the cyano nitrogen atoms to afford a two-fold interpenetrated (6,4) three-dimensional network which is formed by 12 gon cycles having six ruthenium and six cobalt atoms. The metal–metal separations through the cyanide bridge are 5.2491(1)Å for 1, 5.2038(12) and 5.2426(12)Å for 2, 5.2130(12) and 5.2253(12)Å for 3 and 5.1155(15) and 5.1100(15)Å for 4. The magnetic properties of 1–4 together with those of the mononuclear precursor trans-PPh4[Ru(acac)2(CN)2] (PPh4 + =tetraphenylphosphonium cation and Hacac=acetylacetone) were investigated in the temperature range 1.9–295K. The cyano-bearing ruthenium(III) precursor exhibits the magnetic behavior expected for a low-spin distorted octahedral ruthenium(III) system with spin-orbit coupling of the 2T2g ground term. Compound 1 exhibits an overall antiferromagnetic behavior, the magnetic coupling between the nickel(II) ions through the double phenoxo group and that between adjacent ruthenium(III) and nickel(II) centers through the single cyano bridge being −50.0 and +6.6cm−1, respectively. Compounds 2 and 3 behave as ferromagnetic chains. The intrachain magnetic coupling in 3 is +3.2cm−1 whereas that in 2 could not be evaluated because of the lack of a suitable model. No magnetic ordering is observed in 2 and 3 down to 1.9K. Compound 4 shows an overall ferromagnetic behavior and it exhibits ferromagnetic ordering at T c =5.4K. Theoretical calculations based on density functional theory (DFT) have been employed on the trans-[Ru(acac)2(CN)2]− mononuclear complex and on dinuclear fragments of the compounds 1–3 in order to analyze the efficiency of the exchange pathways through the double phenoxo (1) and single cyano bridge (1–3) and to substantiate the exchange coupling parameters involved. [Copyright &y& Elsevier]

Abstract: New hexa-coordinated Ru(III) complexes of the type [Ru(dipic)(EPh3)2X] have been synthesized by reacting 2,6-pyridine dicarboxylic acid (dipicolinic acid, H2dipic) with the appropriate starting complexes [RuX3(EPh3)3] (where X=Cl, Br; E=P, As). The ligand behaves as tridentate dibasic chelate. Dipicolinic acid which was expected to form a bridge between two metal centers, formed only mononuclear complexes, irrespective of the metal to ligand ratio. All the complexes have been characterized by analytical and spectroscopic (IR, electronic and EPR) data. Single-crystal X-ray analysis of the complex [Ru(dipic)(PPh3)2Cl] revealed that the coordination environment around ruthenium metal consists of an NO2P2Cl octahedron with (dipic) occupying equatorial plane. Electrochemical behavior of the complexes was studied using cyclic voltammetry. The new complexes were found to catalyze the oxidation of alcohols to aldehydes using N-methyl morpholine-N-oxide as co-oxidant. [Copyright &y& Elsevier]

Abstract: The reactions of [Ru(PPh3)3Cl2], N-(benzoyl)-N′-(5-R-salicylidene)hydrazines (H2bhsR, R=H, OCH3, Cl, Br and NO2) and triethylamine (1:1:2 mole ratio) in methanol afford mononuclear ruthenium(III) complexes having the general formula trans-[Ru(bhsR)(PPh3)2Cl]. In the case of R=H, a dinuclear ruthenium(III) complex of formula [Ru2(μ-OCH3)2(bhsH)2(PPh3)2] has been isolated as a minor product. The complexes are characterized by elemental analysis, magnetic, spectroscopic and electrochemical measurements. The crystal structures of the dinuclear complex and two mononuclear complexes have been determined. In the dinuclear complex, each metal centre is in distorted octahedral NO4P coordination sphere constituted by the two bridging methoxide groups, one PPh3 molecule and the meridionally spanning phenolate-O, imine-N and amide-O donor bhsH2−. The terminal PPh3 ligands are trans to each other. In the mononuclear complexes, bhsR2− and the chlorine atom form an NO2Cl square-plane around the metal centre and the P-atoms of the two PPh3 molecules occupy the remaining two axial sites to complete a distorted octahedral NO2ClP2 coordination sphere. All the complexes display ligand-to-metal charge transfer bands in the visible region of the electronic spectra. The cryomagnetic measurements reveal the antiferromagnetic character of the diruthenium(III) complex. The low-spin mononuclear ruthenium(III) complexes as well as the diruthenium(III) complex display rhombic EPR spectra in frozen solutions. All the complexes are redox active in CH2Cl2 solutions. Two successive metal centred oxidations at 0.69 and 1.20V (versus Ag/AgCl) are observed for the dinuclear complex. The mononuclear complexes display a metal centred reduction in the potential range −0.53 to −0.27V. The trend in these potential values reflects the polar effect of the substituents on the salicylidene moiety of the tridentate ligand. [Copyright &y& Elsevier]

Abstract: The crystal structures of the complexes [RuCl(Nap-o-phd)(AsPh3)] and [RuBr(Nap-o-phd)(PPh3)] (where H2-Nap-o-phd= N,N′-bis(2-hydroxy-1-naphthaldehyde) o-phenylenediamine) have been determined by single crystal X-ray diffraction techniques. The antibacterial properties of the complexes have also been examined. [Copyright &y& Elsevier]

Abstract: Indazolium trans-[tetrachlorobis(1H-indazole)ruthenate(III)] (KP1019 or FFC14A) is just the second ruthenium-based anticancer agent after NAMI-A which was developed to the stage of clinical trials. Important steps in the mode of action of KP1019 are thought to be the binding to the serum protein transferrin and the transport into the cell via the transferrin pathway. Additionally, the selective activation by reduction in the tumor might contribute to the low side effects observed in in vivo studies. Apoptosis is induced at non-toxic levels via the mitochondrial pathway. These features distinguish it from the established platinum anticancer drugs and suggest that different types of cancer might be treatable with this drug. Indeed, promising activity against certain types of tumors, which are not successfully treatable with cisplatin, and only a very low incidence of acquired resistance has been observed in in vitro and in vivo studies. Recently, a clinical phase I trial was finished in which none of the treated patients experienced serious side effects, while disease stabilization in five of six evaluable patients was achieved. In this review, the preclinical and early clinical development of KP1019 – from bench to bedside – is recapitulated. [Copyright &y& Elsevier]

Abstract: A series of new hexa-coordinated ruthenium(III) complexes of the type [RuX(Nap-o-phd)(EPh3)] (where, H2-Nap-o-phd= N,N′-bis(2-hydroxy-1-naphthaldehyde) o-phenylene diamine; X=Cl or Br; E=P or As) have been prepared by reacting [RuX3(EPh3)3] and [RuBr3(PPh3)2(MeOH)] (where X=Cl or Br; E=P or As) with tetradentate Schiff base ligand (H2-Nap-o-phd) in 1:1 molar ratio. The complexes have been characterized by elemental analyses, infra red, electronic, electron paramagnetic resonance spectroscopy and cyclic voltammetry. The coordination geometry and structure of the complexes have been investigated by extended X-ray absorption fine structure (EXAFS) spectroscopy and an octahedral structure has been proposed. [Copyright &y& Elsevier]

Abstract: A series of new hexa-coordinated ruthenium(III) complexes of the type [Ru(X)(2-atmp-ba)(EPh3)] (where H2-2-atmp-ba=N,N′-bis(2-aminothiophenol)benzoylacetone; X=Cl or Br; E=P or As) have been prepared by reacting [RuX3(EPh3)3] (where X=Cl or Br; E=P or As) with tetradentate Schiff base ligand (H2-2-atmp-ba) in 1:1 molar ratio. The complexes have been characterized by elemental analyses, Infra red, electronic, electron paramagnetic resonance spectroscopy and cyclic voltammetry. In order to confirm the coordination and structure of the complexes extended X-ray absorption fine structure spectroscopy (EXAFS) studies have been carried out. Based on the above data, an octahedral structure has been confirmed for the complexes. The new complexes were also screened for their antibacterial properties. [Copyright &y& Elsevier]

Formation of adducts between the antitumor ruthenium(III) complex [HInd]trans-[RuCl4(Ind)2] (KP1019) and the plasma proteins serum albumin and serum transferrin was investigated by UV–vis spectroscopy, for metal-to-protein ratios ranging from 1:1 to 5:1. In both cases, formation of tight metal–protein conjugates was observed. Similar spectroscopic features were observed for both albumin and transferrin derivatives implying a similar binding mode of the ruthenium species to these proteins. Surface histidines are the probable anchoring sites for the bound ruthenium(III) ions in line with previous crystallographic results. In order to assess the stability of the KP1019-protein adducts the influence of pH, reducing agents and chelators was analysed by UV–vis spectroscopy. Notably, there was no effect of addition of EDTA on the UV–vis spectra of the conjugates. The pH-stability was high in the pH range 5–8. Experiments with sodium ascorbate showed that there was just some alteration of selected bands. The implications of the present results are discussed in relation to the pharmacological behavior of this novel class of antitumor compounds. [Copyright &y& Elsevier]

The redox chemistry and pharmacological studies of the novel blue ruthenium(III)–catecholamine complexes were investigated in aqueous medium and compared to the free catecholamines. The [RuIII(NH3)4(catecholamine)]+ can be oxidized or reduced reversibly in one electron redox couples in aqueous solution. This is in contrast to the free catecholamines, which has a complicated electrochemical behavior due to coupled protonation process. The introduction of the ruthenium group reduces the intrinsic efficacy of the studied catecholamines. The [RuIII(NH3)4(catecholamine)]+ complex aqueous medium is more stable than the free catecholamines ligand in the same conditions. [Copyright &y& Elsevier]