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We have synthesized and characterized three new ruthenium(II) diphosphine complexes containing an acylthiourea ligand, with the general formula [Ru(DPEPhos)(O,S)(bipy)]PF6, where DPEPhos = bis(2-(diphenylphosphino)phenyl)ether, bipy = 2,2′-bipyridine, and O,S = N,N-dimethyl-N′-(benzoyl)thiourea (1), N,N-dimethyl-N′-(furoyl)thiourea (2), and N,N-dimethyl-N′-(thiophenyl)thiourea (3), by several physicochemical techniques. We evaluated the ruthenium complexes for their cytotoxicity against two human cancer cell lines, A549 (lung) and MDA-MB-231 (breast), and two corresponding lines of non-cancer cells, MRC-5 (lung) and MCF-10A (breast). All the complexes are cytotoxic against the cancer cell lines; the IC50 values lie in the micromolar range (0.07–0.70 μM). Ruthenium complex 1 is more selective (7 times more active) toward lung cancer cells (A549) than toward non-cancer cells (MRC-5) and is 160 times more cytotoxic than cisplatin against A549 cells. Investigations of the mechanism of action of complex 1 in A549 cells demonstrated that it inhibits colony formation and promotes cell cycle arrest in the G1 phase and apoptotic cell death. DNA binding studies revealed that complexes 1–3 interact with the biomolecule via minor grooves. These complexes also interact with human serum albumin (HSA) and have affinity for site I by hydrophobic forces. Therefore, this new class of ruthenium complexes can act as cytotoxic agents, mainly for lung cancer treatment. [ABSTRACT FROM AUTHOR]

The complexes trans-[RuIII(NH3)4(4-pic)(H2O)](CF3SO3)3 (1) and [RuIII(NH3)5(4-pic)](CF3SO3)3 (2) were isolated and studied experimentally by electron paramagnetic resonance (EPR) and UV-vis spectroscopies, cyclic voltammetry, and X-ray crystallography and theoretically by ligand-field theory (LFT) and density functional theory (DFT) calculations. Complex 1 is reported in two different crystal forms, 1a (100 K) and 1b (room temperature). EPR and UV-vis spectroscopies suggest that aqua ligand interaction in this low-spin ruthenium(III) complex changes as a function of hydrogen bonding with solvent molecules. This explicit water solvent effect was explained theoretically by DFT calculations, which demonstrated the effect of rotation of the aqua ligand about the Npic-Ru-Oaq axis. The UV-vis spectrum of 1 shows in an aqueous acid solution a broad- and low-intensity absorption band around 28500 cm-1 (ε ≈ 500 M-1 cm-1) that is assigned mainly to a charge-transfer (CT) transition from the equatorial ligands to the Ru β-4dxy orbital (β-LUMO) using DFT calculations. The electronic reflectance spectrum of 1 shows a broad and intense absorption band around 25500 cm-1 that is assigned to a CT transition from 4-picoline to the Ru β-4dxz orbital (β-LUMO) using DFT calculations. The t2g5 set of orbitals had its energy splitting investigated by LFT. LFT analysis shows that a rhombic component arises from C2v symmetry by a simple π-bonding ligand (H2O in our case) twisting about the trans (C2) axis. This twist was manifested in the EPR spectra, which were recorded for 1 as a function of the solvent in comparison with [Ru(NH3)5(4-pic)]3+ and [Ru(NH3)5(H2O)]3+. Only 1 shows an evident change in the g-tensor values, wherein an increased rhombic component is correlated with a higher nucleophilicity (donor) solvent feature, as parametrized by the Abraham system. [ABSTRACT FROM AUTHOR]

Three new homodinuclear complexes containing substituted phenolate-type ligands based on the N5O2 donor (2-(N,N-Bis(2-pyridylmethyl)aminomethyl)-6-(N′,N′-(2-hydroxybenzyl)(2-pyridylmethyl))aminomethyl)-4-methylphenol (H2L-H) were synthesized and characterized by X-ray crystallography. Potentiometric titration studies in 70% (v/v) aqueous ethanol show that all three complexes exhibit a common {CuII(µ-phenoxo)(µ-OH)CuII(OH)} core in solution. Kinetic studies on the oxidation reaction of 3,5-di-tert-butylcatechol revealed that the catalytic activity of the metal complexes increases toward the ligand containing an electron-donating group. In addition, these complexes also carried out DNA cleavage by hydrolytic and oxidative pathways. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The complex fac-[Ru(NO)Cl2(κ³N4,N8,N11 (1-carboxypropyl)cyclam)]Cl · H2O (1-carboxypropyl)cyclam = 3-(1,4,8,11-tetraazacyclotetradecan-1-yI)propionic acid) was prepared in a one pot reaction by mixing equimolar amounts of RuNOCl3 and (1-carboxypropyl)cyclam and was characterized by X-ray crystallography, electrospray ionization tandem mass spectrometry (ESI-MS/MS), elemental analysis, NMR, and electronic and vibrational (IR) spectroscopies. fac-[Ru(NO)Cl2(κ³N4,N8,N11(1-carboxypropyl)cyclam)]Cl · H2O crystallizes in the triclinic, space group P1, No. 2, with unit cell parameters of a = 8.501 (1) Å, b = 9.157(1) Å, c = 14.200(1) Å, α = 72.564(5)°, β = 82.512(5)°, ³ = 80.308(5)°, and Z = 2. The Ru-N interatomic distance and bond angle in the [Ru-NO] unit are 1.739(2) Å and 167.7(2)°, respectively. ESI-MS/MS shows characteristic dissociation chemistry that initiates by HCl or NO loss. The IR spectrum displays a ν(NO) at 1881 cm-1 indicating a nitrosonium character. The electronic spectrum shows absorptions bands at 264 nm (log ε = 3.27), 404 nm (log ε = 2.53), and 532 nm (log ε = 1.88). ¹H and 13C NMR are in agreement with the proposed molecular structure, which shows a very singular architecture where the cyclam ring N (with the carboxypropyl pendant arm) is not coordinated to the ruthenium resulting in a κ³ instead of the expected κ4 denticity. [ABSTRACT FROM AUTHOR]

Abstract: The reaction of lead(II) acetate in methanol with thiosemicarbazones derived from β-keto esters and β-keto amides (HTSCs) afforded two lead(II) thiosemicarbazonates and numerous homoleptic ([PbL2]) and/or heteroleptic ([Pb(OAc)L]) complexes containing deprotonated pyrazolones L− formed by metal-induced cyclization of the starting HTSC ligands. All the complexes isolated were characterized by IR spectroscopy in the solid state and by 1H and 13C NMR spectroscopy in DMSO solution; in addition, crystals containing [Pb(L6)2] and [Pb(L7)2] were examined by X-ray crystallography. [Pb(L6)2]·0.5H2O·0.3MeOH (HL6 =4-ethyl-2,5-dihydro-3-methyl-5-oxo-1H-pyrazole-1-carbothiamide) showed three types of molecule with significant structural differences that appear to be determined by packing interactions. In all three molecules the Pb⋯Pb distances are very short [3.6096(8)–3.7562(8)Å], but density-functional-theoretic calculations at the B3LYP level do not support the existence of Pb–Pb bonds. In [Pb(L7)2] (HL7 = N-ethyl-2,5-dihydro-3-methyl-5-oxo-1H-pyrazole-1-carbothiamide) all the molecules are of a single type, and they are linked in a three-dimensional network by weak intermolecular Pb⋯O bonds. [Copyright &y& Elsevier]

In this work a series of {[RuCl 2 (dppb)](μ-4,4′-N-N)} 4 complexes were synthesized and characterized by elemental analysis, cyclic voltammetry and differential pulse voltammetry and UV-Vis and 31 P{ 1 H} NMR spectroscopies; [(μ-4,4′-N-N=pyrazine (pz), 4,4′-bipyridine=(4,4′-bipy), 1,2-bis- trans -(4-pyridyl)ethane = (pyeta) and 1,2-bis- trans -(4-pyridyl)ethylene=(pyetil) as bridging alterdentate ligands (alterdentate ligands are molecules (or ions), with two equivalent ligating atoms or ligating sites that do not simultaneously bind to a metallic center [Zelewsky von A. in Stereochemistry of Coordination Compounds , Inorganic Chemistry , A Textbook Series; John Wiley & Sons, Inc.: New York, 1995: p. 45] [1] ) and 1,4-bis(diphenylphosphino)butane=dppb]. Electrochemical experiments (cyclic voltammetry and differential pulse voltammetry) suggest that for longer ligands the interaction between two ruthenium atoms is weak and for short ligands like pyrazine the corresponding interaction is strong. The analysis of the X-ray structure of the {[RuCl 2 (dppb)](μ-4,4′-bipy)} 4 complex showed that the molecular squares obtained are stacked on top of each other along the α axis forming infinite columns and that the formation of central tunnels is prevented by the bulky character of the phenyl groups of the diphenylphosphine ligands. [ABSTRACT FROM AUTHOR]

The crystal structure of [Ru(NH3)5(OH2)]2(S2O6)3 · 2H2O has been solved by X-ray diffraction techniques. The relevant average interatomic distances are Ru–(NH3)eq=2.09 A˚, Ru–(NH3)ax=2.08 A˚ and Ru–(OH2)ax=2.11 A˚. The aquation rate (kH2O) and the activation parameters for the reactiontrans-[RuNO(NH3)4Cl]2++H2O→, upper limit kH2O trans-[RuNO(NH3)4(H2O)]3++Cl−have been calculated as 8.4 × 10−6 s−1 (0.10 mol L−1 CF3COOH, μ=0.10 mol L−1, 40 °C), ΔH≠−1=2.3 kcal mol−1, ΔS≠−1=24.0 cal deg−1 mol and ΔG≠−1=8.6 kcal mol−1. A comparison between the structural data, kinetic and thermodynamic reactivities of [Ru(NH3)5(OH2)]3+ and trans-[RuNO(NH3)4(OH2)]3+ ions strongly suggests that the substitution of the trans NH3 ligand in the coordination sphere of [Ru(NH3)5(OH2)]2+ by NO confers a character of Ru(III) to the formally Ru(II) center. [Copyright &y& Elsevier]

The ruthenium(II) complex, [RuCl[sub 2] (NO)L] (I), (L = [(2-py)[sub 2] PC[sub 2] H[sub 4] PO[sub 2] (2-py)][sup -] ) was obtained from recrystallization of RuCl[sub 3] NO(d2pype) (d2pype = (2-py)[sub 2] PC[sub 2] H[sub 4] P(2-py)[sub 2] ) in the presence of HNO[sub 3] , crystallizing in the monoclinic space group P2[sub 1 ] (no. 4), with a = 8.012(4) Å, b = 14.454(4) Å, c = 9.353(3) Å, β = 105.77(3)°, and Z = 2. Crystals of the DMSO solvate of the complex (II) were obtained from (CD[sub 3] )[sub 2] SO solution, crystallizing in the monoclinic space group P2[sub 1] /c (no.14) with a = 9.7080(2) Å, b = 22.2920(5) Å, c = 11.5230(3) Å, β = 92.0450(10)°, and Z = 4. In both complexes, the geometry about the ruthenium atom is a distorted octahedron mainly as a result of the tridentate [P,N,O]-bonding mode of L. The ν (NO) bands at 1875 cm[sup –1] in both complexes are consistent with the linear disposition of the NO group and the Ru atom as is observed in the X-ray crystal structure (Ru-N1-O1 angle = 178.5(4)°).Key words: pyridylphosphine, nitrosyl, ruthenium complex, X-ray structure.La recristallisation du RuCl[sub 3] NO(d2pype) (d2pype = (2-(py)[sub 2] PC[sub 2] H[sub 4] P(2-py)[sub 2] ) en présence de HNO[sub 3] conduit à la formation du complexe de ruthénium(II), [RuCl[sub 2] (NO)L] (1), (L = [(2-py)[sub 2] PC[sub 2] H[sub 4] P(2py)[sub 2] )][sup -] ) qui cristallise dans le groupe d'espace P2[sub 1] (no. 4), avec a = 8,012(4) Å, b = 14,454(4) Å et c = 9,353(3) Å, β = 105,77(3)° et Z = 2. Les cristaux du produit de solvatation du complexe par le DMSO (2) ont été obtenus à partir d'une solution de (CD[sub 3] )[sub 2] SO; ils cristallisent dans le groupe d'espace P2[sub 1] /c (no.14) avec a = 9,7080(2) Å, b = 22,2920(5) Å et c = 11,5230(3) Å, β = 92,0450(10)° et Z = 4. Dans les deux complexes, la géométrie autour de l'atome de ruthénium est un octaèdre déformé en raison principalement du mode de liaison tridentate [P,N,O] de L. Les fréquences des bandes NO, à 1875 cm[sup –1] , dans les deux complexes sont en accord avec une disposition linéaire du groupe NO et de l'atome de Ru; c'est ce qui est observé dans la structure cristalline obtenue par diffraction des rayons X alors que l'angle Ru-N1-O1 est de 178,5(4)°.Mots clés : pyridylphosphine, nitrosyle, complexe du ruthénium, structure cristalline par diffraction des rayons X.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Abstract: A polymeric complex [Eu(α-tpc)3(α-Htpc)2] n and its characterization by single crystal X-ray and thermal analysis, infrared and photoluminescence spectroscopies are described. The compound crystallizes in the monoclinic Cc space group. The asymmetric unit is formed from a europium ion bonded to one carboxyl oxygen of five different thiophene carboxylic moieties. Three of these moieties are deprotonated and bridge between neighboring europium ions giving rise to an infinite polymer along the c axis. Besides the europium characteristic emission lines, the emission spectra show unambiguously the crystal size effect on the 5D0 → 7F0 transition. The complex thermal decomposition at 220°C leads to a stable luminescent complex in which the 5D0 → 7F4 transition reveals a monomeric characteristic. The Judd–Ofelt intensity parameters to the polymeric and the monomeric compound with the same ligand and coordination number were compared. [Copyright &y& Elsevier]

Reaction of trans-Ru(DMSO)4C12 with DMAP (DMAP = 4-dimethylaminopyridine) yields the yellow [Ru(DMAP)6]2~ cation in good yield. The crystal and molecular structure of [Ru(DMAP)6]Cl2.6CH3CH2OH was determined by X-ray diffraction methods. The complex crystallizes in the trigonal F~3 space group with a = b = 16.373(1), c = 20.311(1) A, y = 120°, and Z = 3 molecules per unit cell. The reaction of [Ru(DMAP)6]2~ in aerobic water gives the red [Ru'°(DMAP)5(OH)]2~ cation. This complex shows a chemical behavior similar to [Ru'°(NH3)5Cl]2~ and allows the preparation of a family of [Ru(DMAP)5L]'~ complexes. Their electronic properties indicate that the {Ru°(DMAP)5} fragment is a weaker 7r-donor than {Ru"(NH3)5}. Our density functional theory (DFT) calculations show that in {RuH(DMAP)5} the DMAP ligands can compete for the ~r electron density of the ruthenium making the fragment a weaker ir-donor. [ABSTRACT FROM AUTHOR]

Abstract: The new mononuclear copper(II) complex [CuII(H2LDA)(ClO4)](ClO4) (1) ([H2LDA= N,N′-[bis-(2-hydroxy-3-formyl-5-methylbenzyl)(dimethyl)]-ethylenediamine]) with an unusual coordination mode of a salen derivative ligand is reported. The most interesting feature of 1 is that the ligand is doubly protonated and presents significant intermolecular π-stacking interactions, contributing to the dimer structure stabilization in the solid state and in CH3CN and methanolic solutions. The complex was characterized by X-ray crystallography and shows catecholase-like activity in the oxidation of the substrate 3,5-di-tert-butylcatechol (3,5-dtbc), with the formation of H2O2, which kinetic parameters are similar to those observed in conventional dinuclear bridged CuII complexes. [Copyright &y& Elsevier]

The new trinuclear gadolinium complex [Gd3L2(NO3)2(H2O)4]NO3·8H2O (1) with the unsymmetrical ligand 2-[N-bis-(2-pyridylmethyl)aminomethyl]-4-methyl-6-[N-bis(2-hydroxy-2-oxoethyl)aminomethyl] phenol (H3L) was synthesized and characterized. The new ligand H3L was obtained in good yield. Complex 1 crystallizes in an orthorhombic cell, space group Pcab. Kinetic studies show that complex 1 is highly active in the hydrolysis of the substrate 2,4-bis(dinitrophenyl)phosphate (Km = 4.09 mM, Vmax = 2.68 × 10-2 mM s-1, and kcat = Vmax/[1] = 0.67 s-1). Through a potentiometric study and determination of the kinetic behavior of 1 in acetonitrile/water solution, the species present in solution could be identified, and a trinuclear monohydroxo species appears to be the most prominent catalyst under mild conditions. Complex 1 displays high efficiency in DNA hydrolytic cleavage, and complete kinetic studies were carried out (Km = 4.57 × 10-4 M, k′cat = 3.42 h-1, and k′cat/Km = 7.48 × 103 M-1 h-1). Studies with a radical scavenger (dimethyl sulfoxide, DMSO) showed that it did not inhibit the activity, indicating the hydrolytic action of 1 in the cleavage of DNA, and studies on the incubation of distamycin with plasmid DNA suggest that 1 is regio-specific, interacting with the minor groove of DNA. [ABSTRACT FROM AUTHOR]

Abstract: This study presents the syntheses and characterization of 2-mercaptopyridine (pyS−) complexes containing ruthenium(II) with the following general formula [Ru(pyS)2(P–P)], P–P=(c-dppen)= cis-1,2-bis(diphenylphosphino)ethylene) (1); (dppe)=1,2-bis(diphenylphosphino)ethane (2); (dppp)=1,3-bis(diphenylphosphino)propane (3) and (dppb)=1,4-bis(diphenylphosphino)butane (4). The complexes were synthesized from the mer- or fac-[RuCl3(NO)(P–P)] precursors in the presence of triethylamine in methanol solution with dependence of the product on the P–P ligand. The reaction of pyS− with a ruthenium complex containing a bulky aromatic diphosphine dppb disclosed a major product with a dangling coordinated dppbO-P, the [Ru(pyS)2(NO)(η1-dppbO-P)]PF6 (5). In addition, this work also presents and discusses the spectroscopic and electrochemical behavior of 1–5, and report the X-ray structures for 1 and 5. [Copyright &y& Elsevier]

Abstract: Four new ternary complexes of copper(I) with thiosaccharin and phosphanes were prepared. The reaction of [Cu4(tsac)4(CH3CN)2] (1) (tsac: thiosaccharinate anion) with PPh3 in molar ratios Cu(I)/PPh3 1:075 and 1:2 gave the complexes [Cu4(tsac)4(PPh3)3]·CH3CN (2) and Cu(tsac)(PPh3)2 (3), respectively. The reaction of 1 with Ph2PCH2PPh2 (dppm) in molar ratios Cu(I)/dppm 2:1 and 1:1 gave the complexes [Cu4(tsac)4(dppm)2]·2CH2Cl2 (4) and [Cu2(tsac)2(dppm)2]·CH2Cl2 (5), respectively. All the compounds have been characterized by spectroscopic and X-ray crystallographic methods. Complex 2 presents a tetra-nuclear arrangement with three metal centers in distorted tetrahedral S2NP environments, the fourth one with the Cu(I) ion in a distorted trigonal S2N coordination sphere, and the tsac anions acting as six electron donor ligands in μ3-S2N coordination forms. Complex 3 shows mononuclear molecular units with copper(I) in a distorted trigonal planar coordination sphere, built with the exocyclic S atom of a mono-coordinated thiosaccharinate anion and two P-atoms of triphenylphosphane molecules. With dppm as secondary ligand the structures of the complexes depends strongly on the stoicheometry of the preparation reaction. Complex 4 has a centrosymmetric structure. Two triply bridged Cu2(tsac)2(dppm) units are joined together by the exocyclic S-atoms of two tsac anions acting effectively as bridging tridentate ligands. Complex 5 is conformed by asymmetric dinuclear moieties where the two dppm and one tsac ligands bridge two Cu(I) atoms and the second tsac anion binds one of the metal centers through its exocyclic S-atom. [Copyright &y& Elsevier]

Abstract: The chemistry of Ru(III) complexes containing dmso as a ligand has become an interesting area in the cancer treatment field. Because of this, structural knowledge and chemistry of the moiety Ru(III)–dmso have become important to cancer research. The crystal structures of the compounds mer-[RuCl3(dms)3] (1) and mer-[RuCl3(dms)2(dmso)]:mer-[RuCl3(dms)3] (2) were determined by X-ray crystallography and a speciation of the presence of intramolecular hydrogen bond in these structures has been studied. Compound (1) crystallizes in the orthorhombic space group, Pna21; a =16.591(8)Å, b =8.724(2)Å, c =10.547(3)Å; Z =12 and (2) crystallizes in the space group, P21/C; a =11.9930(2)Å, b =7.9390(2) Å, c =15.8700(3)Å, β =93.266(1)°, Z =2. From the X-ray structures solved in this work, were possible to suggest an interpretation for the broad lines observed in the EPR spectra of the Ru(III) compounds explored here. Also, the exchange interactions detected by EPR spectroscopy in solid state and in solution, confirm the presence of van der Waals interactions such as C–H…Cl in the compounds (1), (2) and (3). The use of techniques such as IR, UV–vis, 1H NMR and EPR Spectroscopy and Cyclic Voltammetry were applied in this work to analyze the behavior of these metallocompounds. [Copyright &y& Elsevier]

Abstract: Novel rhenium complexes containing the maltolate (mal) or kojate (koj) anions as chelating ligands have been synthesized: [ReOCl(mal)2] (1), [ReOCl2(mal)(PPh3)] (2), [ReOBr2(mal)(PPh3)] (3), [ReOCl2(koj)(PPh3)] (4) and [ReOBr2(koj)(PPh3)] (5). The products have been characterized by FTIR, 1H, 13C, and 31P NMR spectroscopies and elemental analysis. The crystal and molecular structures of all complexes were determined. Complex 1 crystallizes monoclinic, space group C2/c, Z =8. It contains two O,O′-bidentate maltolate ligands and one chloro ligand at the (ReO)3+ unit, so that a distorted octahedral geometry is adopted by the six-coordinated rhenium(V) center. The chloro ligand occupies a cis position to the oxo ligand. Complexes 2 and 3 are isostructural and crystallize orthorhombic, space group Pbca and Z =8. The isostructural complexes 4 and 5 crystallize monoclinic, space group P21/n and Z =4. In complexes 2–5, the (ReO)3+ unit is coordinated by a monoanionic O,O-bidentate unit of the maltolate (2 and 3) or kojate (4 and 5) ligand, one triphenylphosphine and two halogeno ligands (Cl in 2 and 4; Br in 3 and 5), with the rhenium(V) center in a distorted octahedral environment. The halide ligands are in cis positions to each other. [Copyright &y& Elsevier]

Abstract: The trans-[RuCl2(dppb)(1,4-dt)], mer-[RuCl3(dppb)(1,4-dt)] and [{RuCl3(dppb)}2(μ-(1,4-dt))] complexes were synthesized and characterized by spectroscopic and electrochemical techniques. Despite the favorable energy for the C 2h conformation, the crystallographic data point for the 1,4-dithiane (1,4-dt) D2 conformer in the trans-[RuCl2(dppb)(1,4-dt)] complex, where it acts as a bidentate ligand. The E 1/2 value of this complex is higher than those found for some related pyridine derivative compounds showing that with this thio-ligand, the Ru(II) atom presents a relatively strong π back-bonding interaction. Apart from the phosphine intraligand transitions, the UV/Vis spectrum of the trans-[RuCl2(dppb)(1,4-dt)] complex shows only one band at 457nm assigned to the MLCT transition. The bands observed in the spectra of the mer-[RuCl3(dppb)(1,4-dt)] and [{RuCl3(dppb)}2(μ-(1,4-dt))] complexes, at 530, 420 and 347nm were attributed to the contribution of the (RuIII)←(Cl,S) LMCT transitions. The EPR spectrum of the mer-[RuCl3(dppb)(1,4-dt)] complex shows three g-values in 2.87, 2.15 and 1.73, suggesting that the 1,4-dt is coordinated in a monodentate mode. The NMR, EPR, FTIR and crystallographic data point for the ruthenium-phosphine species as the first example of metallic system that form complexes with the 1,4-dithiane acting as bidentate, monodentate and bridged ligand. [Copyright &y& Elsevier]