Direct C-H carboxylation with complexes of the coinage metals.

Advances into the functionalisation of C-H bonds by coinage metal complexes that make use of carbon dioxide are described.

Backbone tuning in indenylidene-ruthenium complexes bearing an unsaturated N-heterocyclic carbene.

The steric and electronic influence of backbone substitution in IMes-based (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) N-heterocyclic carbenes (NHC) was probed by synthesizing the [RhCl(CO)₂(NHC)] series of complexes to quantify experimentally the Tolman electronic parameter (electronic) and the percent buried volume (%V(bur), steric) parameters. The corresponding ruthenium-indenylidene complexes were also synthesized and tested in benchmark metathesis transformations to establish possible correlations between reactivity and NHC electronic and steric parameters.

Halide exchanged Hoveyda-type complexes in olefin metathesis.

The aims of this contribution are to present a straightforward synthesis of 2(nd) generation Hoveyda-type olefin metathesis catalysts bearing bromo and iodo ligands, and to disclose the subtle influence of the different anionic co-ligands on the catalytic performance of the complexes in ring opening metathesis polymerisation, ring closing metathesis, enyne cycloisomerisation and cross metathesis reactions.

High-mobility group box protein 1: a novel mediator of inflammatory-induced renal epithelial-mesenchymal transition.

Background: high-mobility group box protein 1 (HMGB-1) is a chromatin-binding protein that bends DNA, thereby facilitating gene transcription. HMGB-1 has also been observed as an extracellular secreted protein in serum of patients with sepsis and has putative intracellular signalling effects regulating the production of interleukin-1 and tumour necrosis factor in a number of inflammatory conditions.

Methods: we established a model of immune-mediated epithelial-mesenchymal transition (EMT) in human proximal tubular epithelial cells (PTECs).

Protective efficacy of BCG overexpressing an L,D-transpeptidase against M. tuberculosis infection.

Background: M. bovis Bacille Calmette-Guérin (BCG), currently the only available vaccine against tuberculosis (TB), fails to adequately protect individuals from active and latent TB infection. New vaccines are desperately needed to decrease the worldwide burden of TB.

The development and catalytic uses of N-heterocyclic carbene gold complexes.

Gold has emerged as a powerful synthetic tool in the chemist's arsenal. From the early use of inorganic salts such as AuCl and AuCl(3) as catalysts, the field has evolved to explore ligands that fine-tune reactivity, stability, and, more recently, selectivity in gold-mediated processes. Substrates generally contain alkenes or alkynes, and they usually involve straightforward protocols in air with solvents that can often times be of technical grade.

Ligand influence in the selective gold-mediated synthesis of allenes.

The use of [(IPr)AuOH] permits the generation of gold(i)-amine complexes by a silver-free protocol. These in situ or well-defined complexes are used in a straightforward synthetic route to substituted allenes from propargylic acetates. The catalytic activity can be modulated as a function of the nature of the ligand bound to the gold-NHC moiety.

A combined mechanistic and computational study of the gold(I)-catalyzed formation of substituted indenes.

Substituted indenes can be prepared after a sequence [1,3] O-acyl shift-hydroarylation-[1,3] O-acyl shift. Each step is catalyzed by a cationic NHC-Gold(I) species generated in situ after reaction between [(IPr)AuOH] and HBF(4)·OEt(2). This interesting silver-free way is fully supported by a computational study justifying the formation of each intermediate.

Development of versatile and silver-free protocols for gold(I) catalysis.

The use of a versatile N-heterocyclic carbene (NHC) gold(I) hydroxide precatalyst, [Au(OH)(IPr)], (IPr=N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) permits the in situ generation of the [Au(IPr)](+) ion by simple addition of a Brønsted acid. This cationic entity is believed to be the active species in numerous catalytic reactions. (1)H NMR studies in several solvent media of the in situ generation of this [Au(IPr)](+) ion also reveal the formation of a dinuclear gold hydroxide intermediate [{Au(IPr)}(2)(μ-OH)], which is fully characterized and was tested in gold(I) catalysis.

A versatile gold synthon for acetylene C-H bond activation.

The reaction of N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold hydroxide ([Au(OH)(IPr)]; 1) with acetylene and trimethylsilylacetylene derivatives cleanly leads to the formation of a gold-acetylide bond with the concomitant formation of water or trimethylsilanol. All compounds were isolated in high yield (>85%). The crystal structures of selected gold acetylides in conjunction with their UV-vis absorption/emission properties were investigated.

Anti-plasminogen antibodies compromise fibrinolysis and associate with renal histology in ANCA-associated vasculitis.

Antibodies recognizing plasminogen, a key component of the fibrinolytic system, associate with venous thrombotic events in PR3-ANCA vasculitis. Here, we investigated the prevalence and function of anti-plasminogen antibodies in independent UK and Dutch cohorts of patients with ANCA-associated vasculitis (AAV). We screened Ig isolated from patients (AAV-IgG) and healthy controls by ELISA.

Mechanism of racemization of chiral alcohols mediated by 16-electron ruthenium complexes.

Experimental and computational analyses provide support for the existence of a metal-hydride-based mechanism for the ruthenium-mediated racemization of chiral alcohols.

Effect of morbidity and mortality peer review on nurse accountability and ventilator-associated pneumonia rates.

Objective: This program was designed to evaluate the effect of morbidity and mortality peer review conferences (MMPRCs) for ventilator-associated pneumonia (VAP) on nurse accountability and compliance with evidence-based VAP prevention practices.

Background: Ventilator-associated pneumonia is associated with longer average length of stay (ALOS), greater cost, and increased morbidity and mortality. Traditionally, passive or punitive methods have been used to reduce undesirable outcomes.

Recombinant human parainfluenza virus type 2 with mutations in V that permit cellular interferon signaling are not attenuated in non-human primates.

The HPIV2 V protein inhibits type I interferon (IFN) induction and signaling. To manipulate the V protein, whose coding sequence overlaps that of the polymerase-associated phosphoprotein (P), without altering the P protein, we generated an HPIV2 virus in which P and V are expressed from separate genes (rHPIV2-P+V). rHPIV2-P+V replicated like HPIV2-WT in vitro and in non-human primates.

[(NHC)CuX] complexes: synthesis, characterization and catalytic activities in reduction reactions and Click chemistry. On the advantage of using well-defined catalytic systems.

The preparation of three series of [(NHC)CuX] complexes (NHC = N-heterocyclic carbene, X = Cl, Br, or I) is reported. These syntheses are high yielding and only use readily available starting materials. The prepared complexes were spectroscopically and structurally characterized.

The influence of phosphane ligands on the versatility of ruthenium-indenylidene complexes in metathesis.

The aim of the present study is to develop readily available and stable pre-catalysts that could be easily prepared on large scale from simple starting materials. Based on the hypothesis that substitution of classical PCy(3) with phosphanes of varying electron-donating properties could be a straightforward manner to improve catalytic activity, a methodical study dealing with the effect of phosphane fine-tuning in ruthenium-indenylidene catalysts was performed. Challenged to establish how the electronic properties of para-substituted phosphane ligands translate into catalyst activity, the versatile behaviour of these new ruthenium-indenylidene complexes was investigated for a number of metathesis reactions.

Chemoselective olefin metathesis transformations mediated by ruthenium complexes.

Over the past decade, ruthenium-mediated metathesis transformations, including polymerization reactions, cross-metathesis, ring-closing metathesis, enyne metathesis, ring-rearrangement metathesis, and also tandem processes, represent one of the most studied families of organic reactions. This has translated into the development of a large number of structurally diverse catalysts. Whereas most of these investigations are focused on determining catalytic performance, only rare examples of studies dealing with chemoselectivity have been reported to date.

Carboxylation of C-H bonds using N-heterocyclic carbene gold(I) complexes.

A highly efficient [(NHC)Au(I)]-based (NHC = N-heterocyclic carbene) catalytic system for the carboxylation of aromatic and heteroaromatic C-H bonds was developed. The significant base strength of the Au-OH species is at the origin of the activation process and permits the facile functionalization of C-H bonds without the use of other organometallic reagents.

Synthesis and characterization of IPr(Me)-containing silver(I), gold(I) and gold(III) complexes.

The compounds 4,5-dimethyl-N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene silver chloride [AgCl(IPr(Me))] and 4,5-dimethyl-N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold(I) chloride [AuCl(IPr(Me))] have been synthesized. The attempted synthesis of the corresponding 4,5-dimethyl-N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold(III) chloride by oxidative addition of chlorine gas on allowed for the formation of the expected complex, concomitantly with , resulting from a chlorination of a methyl group situated in the backbone of the NHC (N-heterocyclic carbene). Additionally, the buried volume %V(bur) of the IPr(Me) ligand in [AgCl(IPr(Me))] and [AuCl(IPr(Me))] complexes was calculated and compared to %V(bur) of more classical NHCs.

The impact of mouse passaging of Mycobacterium tuberculosis strains prior to virulence testing in the mouse and guinea pig aerosol models.

Background: It has been hypothesized that the virulence of lab-passaged Mycobacterium tuberculosis and recombinant M. tuberculosis mutants might be reduced due to multiple in vitro passages, and that virulence might be augmented by passage of these strains through mice before quantitative virulence testing in the mouse or guinea pig aerosol models.

Methodology/principal Findings: By testing three M.

Flexible cycloalkyl-substituted N-heterocyclic carbenes.

The use of two metal systems cis-Pt(NHC)(2)Me(2) and cis-Ir(NHC)(CO)(2)Cl help to highlight the flexibility of a series of cycloalkyl-substituted N-heterocyclic carbene ligands (ICy, ICy(7), ICy(8), ICy(12)). Bond dissociation enthalpies of several N-heterocyclic carbenes (NHCs) in cis-Pt(NHC)(2)Me(2) are estimated. Electronic and steric parameters of the ICy(n) ligands are quantified and discussed.

A N-heterocyclic carbene gold hydroxide complex: a golden synthon.

The synthesis and complete characterisation of a well-defined N-heterocyclic carbene bearing gold hydroxide complex, [Au(OH)(IPr)], is reported. Its reaction chemistry appears rich and diverse.

Modified [(IPr)Pd(R-acac)Cl] complexes: influence of the acac substitution on the catalytic activity in aryl amination.

The synthesis of a series of [(IPr)Pd(R-acac)Cl] precatalysts (acac=acetylacetonato; IPr=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), where the acac ligand on palladium has been systematically modified through terminal substitution, is reported. The following substituted acac ligands are employed in this study: dibenzoylmethanato (dbm), benzoylacetonato (bac), tetramethylheptanedionato (tmhd), and hexafluoroacetylacetonato (hfac). Full spectroscopic characterization of the new complexes is provided along with X-ray studies for three of these.