Ruthenium(II) complexes with 2-(diphenylphosphinomethyl)aniline

2-(Diphenylphosphinomethyl)aniline. H2L1, reacts with [RuCl2(PPh3)(3)] to yield the monomeric complexes [RuCl2(H2L1)(PPh3)(CH3CN)], [RuCl2(H2L1)(2)]and the chloro-bridged dimer [(H2L1)(PPh3)Ru(mu-Cl)(2)Ru(PPh3) (H2L1)] depending on the conditions applied. Exclusively the monochelate [RuCl2 (H2L1)(dmso)(2)] is formed during reactions of H2L1 with [RuCl2(dmso)(4)]. H2L1 acts as a neutral, bidentate ligand in all complexes. The products are studied spectroscopically and by X-ray diffraction. (C) 2012 Elsevier Ltd. All rights reserved.

Actions of translocator protein ligands on neutrophil adhesion and motility induced by G-protein coupled receptor signaling

The 18 kDa translocator protein (TSPO) also known as the peripheral benzodiazepine receptor (PBR), mediates the transportation of cholesterol and anions from the outer to the inner mitochondrial membrane in different cells types. Although recent evidences indicate a potential role for TSPO in the development of inflammatory processes, the mechanisms involved have not been elucidated. The present study investigated the ability of the specific TSPO ligands, the isoquinoline carboxamide PK11195 and benzodiazepine Ro5-4864, on neutrophil recruitment promoted by the N-formylmethionyl-leucyl-phenylalanine peptide (fMLP), an agonist of G-protein coupled receptor (GPCR). Pre-treatment with Ro5-4864 abrograted fMLP-induced leukocyte-endothelial interactions in mesenteric postcapillary venules in vivo. Moreover, in vitro Ro5-4864 treatment prevented fMLP-induced: (i) L-selectin shedding and overexpression of PECAM-1 on the neutrophil cell surface; (ii) neutrophil chemotaxis and (iii) enhancement of intracellular calcium cations (iCa(+2)). Intriguingly, the two latter effects were augmented by cell treatment with PK11195. An allosteric agonist/antagonist relation may be suggested, as the effects of Ro5-4864 on fMLP-stimulated neutrophils were reverted by simultaneous treatment with PK11195. Taken together, these data highlight TSPO as a modulator of pathways of neutrophil adhesion and locomotion induced by GPCR, connecting TSPO actions and the onset of an innate inflammatory response. (C) 2011 Elsevier Inc. All rights reserved.

Spectroscopic characterization and crystal structure of cis-Bis(N-(2-benzoyl)-N ',N '-diphenylthioureato-k O-2,S)nickel(II)

The title compound [Ni(C20H15N2OS)(2)] is prepared by the reaction of metal acetate with the corresponding acylthiourea derivative. The complex is characterized by elemental analysis, IR, H-1 and C-13 NMR, and its structure is determined by single crystal X-ray diffraction. The Ni(II) ion is coordinated by the S and O atoms of two N-benzoyl-N',N'-diphenylthiourea ligands in a slightly distorted square-planar coordination geometry. The two O and two S atoms are mutually cis to each other. The substance crystallizes triclinic (P-1 space group) with cell dimensions a = 10.7262(9) , b = 12.938(3) , c = 14.2085(12) , alpha = 74.650(4)A degrees, beta = 78.398(4)A degrees, gamma = 68.200(5)A degrees, and two formula units in the unit cell. The structure is very close to the related N-(2-furoyl) Ni complex reported previously.

The nature of Ru-NO bonds in ruthenium tetraazamacrocycle nitrosyl complexes-a computational study

Ruthenium complexes including nitrosyl or nitrite complexes are particularly interesting because they can not only scavenge but also release nitric oxide in a controlled manner, regulating the NO-level in vivo. The judicious choice of ligands attached to the [RuNO] core has been shown to be a suitable strategy to modulate NO reactivity in these complexes. In order to understand the influence of different equatorial ligands on the electronic structure of the Ru-NO chemical bonding, and thus on the reactivity of the coordinated NO, we propose an investigation of the nature of the Ru-NO chemical bond by means of energy decomposition analysis (EDA), considering tetraamine and tetraazamacrocycles as equatorial ligands, prior to and after the reduction of the {RuNO}(6) moiety by one electron. This investigation provides a deep insight into the Ru-NO bonding situation, which is fundamental in designing new ruthenium nitrosyl complexes with potential biological applications.

The In Vitro and In Vivo Antitumour Activities of Nitrosyl Ruthenium Amine Complexes

Ruthenium compounds of the type trans-[Ru(NO)(NH3)(4)(L)] X-3, L = N-heterocyclic ligands, P(OEt)(3), SO32-, X BF4- or PF6-, or [Ru(NO)Hedta], were tested for antitumour activity in vitro against murine melanoma and human tumour cells. The ruthenium complexes induced DNA fragmentation and morphological alterations suggestive of necrotic tumour cell death. The calculated IC50 values were lower than 100 mu M. Complexes for which L = isn or imN were partially effective in vivo in a syngeneic model of murine melanoma B16F10, increasing animal survival. In addition, the same ruthenium complexes effectively inhibited angiogenesis of HUVEC cells in vitro. The results suggest that these nitrosyl complexes are a promising platform to be explored for the development of novel antitumour agents.

Formation of thin luminescent Eu3+-LB films by in situ coordination with 2,3,5,6-tetra(2 '-pyridyl)pyrazine and 1-octadecanol in pure and mixed Langmuir monolayers

The in situ complexation between 2,3,5,6-tetra(2-pyridyl)pyrazine (tppz) molecules and europium ions at the air-liquid interface by means of mixed 1-octadecanol Langmuir films is reported. These films were transferred to solid supports by means of the Langmuir-Blodgett (LB) technique. The EDS maps attested the homogeneity of the LB films as well as the presence of the europium ions. The mixed alcohol/tppz LB film contained a larger amount of europium ions as compared to the pure octadecanol LB film. This work reports the production of a thin luminescent Eu3+ film containing europium ions using only alcohol molecules as ligands an unexpected result, since it is well known that there is an occurrence of non-radiative deactivation of excited europium by hydroxyl groups. Europium ion multiple binding sites were detected from lifetime decay measurements of these films in the presence of tppz molecules. (C) 2012 Elsevier B.V. All rights reserved.

Structural, spectral and potentiometric characterization, and antimicrobial activity studies of [Zn(phen)(2)(cnge)(H2O)](NO3)(2)∙H2O

An octahedral Zn complex with o-phenanthroline (o-phen) and cyanoguanidine (cnge) has been synthesized and characterized. The crystal structural data show the formation of a ZnN5O core where the metal coordinates to two mutually perpendicular o-phenanthrolines as bidentate ligands [Zn-N bond lengths in the 2.124(2)-2.193(2) angstrom range], the cyanide nitrogen of a cnge [d(Zn-N) = 2.092(2) angstrom, angle(Zn-N-C) = 161.1(2)degrees], and a water molecule [d(Zn-Ow) = 2.112(2) angstrom]. Spectral data (FT-IR, Raman, and fluorescence) and speciation studies are in agreement with the structure found in the solid state and the one proposed to exist in the solution. To evaluate the changes in the microbiological activity of Zn, antibacterial studies were carried out by observing the changes in minimum inhibitory concentration of the complex, the ligands, and the metal against five different bacterial strains. The antibacterial activity of Zn improved upon complexation in three of the tested strains.

Increasing the activity of copper(II) complexes against Leishmania through lipophilicity and pro-oxidant ability

Copper complexes with fluorinated beta-diketones were synthesized and characterized in terms of lipophilicity and peroxide-assisted oxidation of dihydrorhodamine as an indicator of redox activity. The biological activity of the complexes was tested against promastigotes of Leishmania amazonensis. Inhibition of trypanosomatid-specific trypanothione reductase was also tested. It was found that the highly lipophilic and redox-active bis(trifluoroacetylacetonate) derivative had increased toxicity towards promastigotes. These results indicate that it is possible to modulate the activity of metallodrugs based on redox-active metals through the appropriate choice of lipophilic chelators in order to design new antileishmanials. Further work will be necessary to improve selectivity of these compounds against the parasite.

Synthesis and characterization of [Ru(eta(6)-C10H14)(dppf)X][PF6] (X = Cl, Br, I, SnF3) compounds: The X-ray structure of [Ru(eta(6)-C10H14)(dppf)Cl][SnCl3]center dot 0.45CH(2)Cl(2)

The arene-ruthenium complex [Ru(eta(6)-C10H14)(dppf)Cl]PF6 (1) was used as a precursor for the syntheses of the [Ru(eta(6)-C10H14)(dppf)Br]PF6 (2), [Ru(eta(6)-C10H14)(dppf)I]PF6 (3). [Ru(eta(6)-C10H14)(dppf)SnF3]PF6 (4) and [Ru(eta(6)-C10H14)(dppf)Cl][SnCl3]center dot 0.45CH(2)Cl(2) (5) complexes by its reactions with KBr, Kl, SnF2 and SnCl2. respectively. All of the compounds were characterized by NMR, IR, Fe-57 and Sn-119-Mossbauer spectroscopy, and cyclic voltammetry. The single-crystal X-ray structure analysis of the [Ru(eta(6)-C10H14)(dppf)Cl] [SnCl3]center dot 0.45CH(2)Cl(2) complex revealed the expected piano-stool geometry. Cyclic voltammograms of the complexes showed only one quasi-reversible electrochemical process, involving the oxidation of Fe(II) and Ru(II) at the same potential, which was confirmed by exhaustive electrolysis experiments. Fe-57-Mossbauer parameters obtained for the complexes (1-5) were fitted with one doublet corresponding to a site of one iron(II). The Sn-119-Mossbauer parameters of the complex (4) indicate that tin is tetra covalent. (c) 2012 Elsevier Ltd. All rights reserved.

Crystal structure and spectroscopic properties of polymeric adducts of the tetra-mu-haloaspirinate-dicopper(II)

Eight new copper(II) complexes with halo-aspirinate anions have been synthesized: [Cu-2(Fasp)(4)(MeCN)(2)] center dot 2MeCN (1), [Cu-2(Clasp)(4)(MeCN)(2)]center dot 2MeCN (2), [Cu-2(Brasp)(4) (MeCn)(2)] center dot 2MeCn (3), {[Cu-2(Fasp)(4)(Pyrz)] center dot 2MeCN}(n) (4) {[Cu-2(Clasp)(4)(Pyrz)] center dot 2MeCN}(n) (5), [Cu-2(Brasp)(4)(Pyrz)](n) (6), [Cu-2(Clasp)(4)(4,4'-Bipy)](n) (7), and [Cu-2(Brasp)(4)(4,4'-Bipy)](n) (8) (Fasp: fluor-aspirinate; Clasp: chloro-aspirinate; Brasp: bromo-aspirinate; MeCN: acetonitrile; Pyrz: pyrazine; 4,4'-Bipy: 4,4'-bipyridine). The crystal structure of two 2 and 4 have been determined by X-ray diffraction methods. All compounds have been studied employing elemental analysis, IR, and UV-Visible spectroscopic techniques. The results have been compared with previous data reported for complexes with similar structures.

Mixed-valence state of symmetric diruthenium complexes: synthesis, characterization, and electron transfer investigation

Complexes of the type {[(pyS)Ru(NH3)(4)](2)-mu-L}(n), where pyS = 4-mercaptopyridine, L = 4,4'-dithiodipyridine (pySSpy), pyrazine (pz) and 1,4-dicyanobenzene (DCB), and n = +4 and +5 for fully reduced and mixed-valence complexes, respectively, were synthesized and characterized. Electrochemical data showed that there is electron communication between the metal centers with comproportionation constants of 33.2, 1.30 x 10(8) and 5.56 x 10(5) for L = pySSpy, pz and DCB, respectively. It was also observed that the electronic coupling between the metal centers is affected by the p-back-bonding interaction toward the pyS ligand. Raman spectroscopy showed a dependence of the intensity of the vibrational modes on the exciting radiations giving support to the assignments of the electronic transitions. The degree of electron communication between the metal centers through the bridging ligands suggests that these systems can be molecular wire materials.

Tricarbonyltechnetium(I) and -rhenium(I) complexes with N '-thiocarbamoylpicolylbenzamidines

N,N-Dialkylamino(thiocarbonyl)-N'-picolylbenzamidines react with (NEt4)(2)[M(CO)(3)X-3] (M = Re, X = Br: M = Tc, X = Cl) under formation of neutral [M(CO)(3)L] complexes in high yields. The monoanionic NNS ligands bind in a facial coordination mode and can readily be modified at the (CS)(NRR2)-R-1 moiety. The complexes [Tc-99(CO)(3)(L-PyMor)] and]Re(CO)(3)(L)] (L = L-PyMor, L-PyEt) were characterized by X-ray diffraction. Reactions of [Tc-99m(CO)(3)(H2O)(3)](+) with the N'-thiocarbamoylpicolylbenzamidines give the corresponding Tc-99m complexes. The ester group in HLPyCOOEr allows linkage between biomolecules and the metal core. (C) 2012 Elsevier Ltd. All rights reserved.

Measurement and model calculation of the temperature dependence of ligand-to-metal energy transfer rates in lanthanide complexes

Temperature dependent transient curves of excited levels of a model Eu3+ complex have been measured for the first time. A coincidence between the temperature dependent rise time of the 5D0 emitting level and decay time of the 5D1 excited level in the [Eu(tta)3(H2O)2] complex has been found, which unambiguously proves the T1→5D1→5D0 sensitization pathway. A theoretical approach for the temperature dependent energy transfer rates has been successfully applied to the rationalization of the experimental data.

Sintesi e coordinazione di leganti Ciclopentadienilici O-Multifunzionalizzati

The introduction of hydroxyl groups into ligands is able to transfer high hydrophilic features to the related metal systems. The atom-economy synthetic procedure adopted which consists in the one-step Cyclopentene-oxide ring opening, quantitatitatively affords stereoselective formation of the multi-hydroxyl rac-1,2,4- C5H2[CH(CH2)3CHOH]3 Cpººº ligand1. Rh complexation of Cpººº gives rise to a novel class of water-soluble complexes (L,L)RhCpººº (LL=NBD 1, COD 2, CH2CH2 3, CO 4) (Scheme 1) characterized by their spectroscopic features (ESI-MS, IR, 2D NMR, n.O.e.). The X-ray diffraction studies of 1a reveal the occurrence of one couple of enantiomeric pairs in the crystal structure, whilst the crystal packing shows an interesting self-organization in chains of dimeric units of 1a, promoted by strong intermolecular hydroxyl H-bonding. This effect has been exploited by performing VT NMR experiments in different solvents (CDCl3, Py, DMSO). Unpredictably, in the absence of chiral tag, 1 exhibits solvent-dependent chiroptical properties (CD, αD^ 25), which are correlated to UV transitions and DFT calculations. The intra/inter molecular H-binding is crucial in driving the equilibrium between the observed atropisomers 1a and 1b, by varying the planar chirality on the two π-complexes.

Polymerisationskatalysatoren auf Basis von Titan- und Vanadiumkomplexen mit Bisphenolato-Liganden

Die Synthese und Charakterisierung von Bisphenolato-Komplexen des Titans und Vanadiums werden beschrieben.Neben dem Methylkomplex wurde eine Reihe von Bisphenolato-Komplexen des Titan(IV) der Zusammensetzung (tbmp)(o-C6H4CH2NMe2)TiX (mit X = CH2SiMe3, CH2Ph, OTf) synthetisiert. Der Methylkomplex wurde mit B(C6F5)3 oder (tbmp)(tbmpH)Al zum Komplexkation [(tbmp)(o-C6H4CH2NMe2)Ti]+ umgesetzt und dessen Reaktivität gegenüber 1-Olefinen untersucht.Ausgehend von (tbmp)TiCl2 wurden der Dimethylkomplex (tbmp)TiMe2 und der Dibenzylkomplex (tbmp)Ti(CH2Ph)2 dargestellt und strukturell charakterisiert. Der Dibenzylkomplex liegt im Kristall als Dimer vor, verbrückt über ein Dioxan-Molekül, während der Dimethylkomplex auch im Feststoff monomer ist. Dies ist das erste Beispiel für die Koordinationszahl fünf bei Bisphenolato-Titan-Komplexen.Polymerisationsversuche mit (tbmp)TiMe2 und B(C6F5)3 weisen auf eine hohe Reaktivität und geringe Stabilität des aktivierten Komplexes hin, die zu geringen Polymer-Ausbeuten führt.Im Falle des Vanadiums konnten trotz Schwierigkeiten aufgrund der hohen Redoxaktivität dieses Elements mehrere Komplexe dargestellt werden. Synthetisiert und strukturell charakterisiert wurden der Komplex (mbmp)V(O)(CH2SiMe3)·B(C6F5)3, das erste Beispiel für ein Boranaddukt eines Oxokomplexes des fünfwertigen Vanadiums, und der erste Di(bisphenolato)-Komplex des vierwertigen Vanadiums, (tbmp)2V.Desweiteren gelang die Darstellung von (mbmp)V(O)(CH2SiMe2Ph)·B(C6F5)3, (tbmp)VCl(THF)2 und (mbmp)2V. Die Alkylkomplexe des fünfwertigen Vanadiums waren mit B(C6F5)3 für die Polymerisation von Ethen nicht aktivierbar. Hingegen bildete (tbmp)VCl(THF)2 mit DEAC ein sehr aktives System für die Polymerisation von Ethen.