Electrophilicity of neutral square-planar organosilver(III) compounds

Neutral Ag(III) complexes stabilised with just monodentate ligands are here unambiguously established. In a series of square-planar (CF3)3Ag(L) compounds with hard and soft Group 15 donor ligands, L, the metal center has been found to exhibit substantial acidity favouring apical coordination of an additional ligand under no coordination constraints

The Listening Network and Cochlear Implant Benefits in Hearing-Impaired Adults

Older adults with mild or no hearing loss make more errors and expend more effort listening to speech. Cochlear implants (CI) restore hearing to deaf patients but with limited fidelity. We hypothesized that patient-reported hearing and health-related quality of life in CI patients may similarly vary according to age. Speech Spatial Qualities (SSQ) of hearing scale and Health Utilities Index Mark III (HUI) questionnaires were administered to 543 unilaterally implanted adults across Europe, South Africa, and South America. Data were acquired before surgery and at 1, 2, and 3 years post-surgery. Data were analyzed using linear mixed models with visit, age group (18–34, 35–44, 45–54, 55–64, and 65+), and side of implant as main factors and adjusted for other covariates. Tinnitus and dizziness prevalence did not vary with age, but older groups had more preoperative hearing. Preoperatively and postoperatively, SSQ scores were significantly higher (¿0.75–0.82) for those aged <45 compared with those 55+. However, gains in SSQ scores were equivalent across age groups, although postoperative SSQ scores were higher in right-ear implanted subjects. All age groups benefited equally in terms of HUI gain (0.18), with no decrease in scores with age. Overall, younger adults appeared to cope better with a degraded hearing before and after CI, leading to better subjective hearing performance.

Selective synthesis of an elusive C -functional bis-cyclam and study of its inhibition of the CXCR4 chemokine receptor

International audienceThis article presents the controlled synthesis of a rare example of C,C′-linked bis-cyclam architecture in mild conditions through the “bis-aminal” route previously used for the advantageous synthesis of cyclam, N- and C-functional cyclams and N,N′-bis-cyclams. Two synthetic pathways were explored with the smart design of α,β-unsaturated ketones or alkyl halides bis-cyclizing agents. The first led to the isolation of a key intermediate for the future design of N-functionalized bis-cyclams, whereas the second allowed the preparation of the targeted C,C′-xylylene-bis-cyclam under mild conditions with decent yield. This compound was then studied as a CXCR4 receptor inhibitor, one of the main applications known for bis-macrocyclic compounds, in particular in the context of HIV (human immunodeficiency virus) infection. Although results demonstrated that its potency is lower (i.e. 137-fold higher IC50) than the gold standard AMD3100 against HIV infection, clear evidence of CXCR4 inhibition is presented, confirming the potential of this novel architecture and related compounds in this research field

Copper(I) complexes derived from mono- and diphosphino-boranes: Cu→b interactions supported by arene coordination

cited By 66International audienceThe monophosphino-boranes o-iPr2P(C6H 4)BR2 (1: R = Ph and 3: R = Cy) and diphosphino-boranes [o-R2P(C6H4)]2BPh (5: R = Ph and 6: R = iPr) readily react with CuCl to afford the corresponding complexes [o-iPr2P(C6H4)BPh2]Cu(μ-Cl) 2 2, [o-iPr2P(C6H4)BCy 2]Cu(μ-Cl)2 4, [o-Ph2P(C6H 4)]2BPhCuCl 7, and [o-iPr2P(C 6H4)]2BPhCuCl 8. The presence of Cu→B interactions supported by arene coordination within complexes 2, 7, and 8 has been unambiguously evidenced by NMR spectroscopy and X-ray diffraction studies. The unique η2-BC coordination mode adopted by complexes 7 and 8 has been thoroughly analyzed by density-functional theory (DFT) calculations. © 2009 American Chemical Society

Synthesis and evaluation of α-ketotriazoles and α,β-diketotriazoles as inhibitors of Mycobacterium tuberculosis

Two series of α-ketotriazole and α,β-diketotriazole derivatives were synthesized and evaluated for antitubercular and cytotoxic activities. Among them, two α,β-diketotriazole compounds, 6b and 9b, exhibited good activities (minimum inhibitory concentration = 7.6 μM and 6.9 μM, respectively) on Mycobacterium tuberculosis and multi-drug resistant M. tuberculosis strains and presented no cytotoxicity (IC50 > 50 μM) on colorectal cancer HCT116 and normal fibroblast GM637H cell lines. These two compounds represent promising leads for further optimization

A Significant but Constrained Geometry Pt→Al Interaction: Fixation of CO2 and CS2, Activation of H2 and PhCONH2

International audienc

Design, chemical synthesis of 3-(9H-fluoren-9-yl)pyrrolidine-2,5-dione derivatives and biological activity against enoyl-ACP reductase (InhA) and Mycobacterium tuberculosis.

We report here the discovery, synthesis and screening results of a series of 3-(9H-fluoren-9-yl)pyrrolidine-2,5-dione derivatives as a novel class of potent inhibitors of Mycobacterium tuberculosis H37Rv strain as well as the enoyl acyl carrier protein reductase (ENR) InhA. Among them, several compounds displayed good activities against InhA which is one of the key enzymes involved in the type II fatty acid biosynthesis pathway of the mycobacteria cell wall. Furthermore, some exhibited promising activities against M. tuberculosis and multi-drug resistant M. tuberculosis strains

Group 10 and 11 metal boratranes (Ni, Pd, Pt, CuCl, AgCl, AuCl, and Au +) derived from a triphosphine-borane

cited By 128International audienceThe ambiphilic triphosphine-borane ligand 1 TPB = [o-iPr 2P-(C6H4)]3B readily coordinates to all group 10 and 11 metals to afford a complete series of metal boratranes (TPB)[M] 2-8 (2: M = Ni, 3: M = Pd, 4: M = Pt, 5: M = CuCl, 6: M = AgCl, 7: M = AuCl, 8: M = Au+). Spectroscopic and structural characterization unambiguously establishes the presence of M→B interactions in all of these complexes. The first evidence for borane coordination to copper and silver is provided, and the Au→B interaction is shown to persist upon chloride abstraction. Experimental and theoretical considerations indicate that the M→B interaction is strongest in the Pt and Au complexes. The influence of the oxidation state and charge of the metal is substantiated, and the consequences of relativistic effects are discussed. The coordination of the σ-acceptor borane ligand is found to induce a significant bathochromic shift of the UV-vis spectra, the Ni, Pd, and Pt complex presenting strong absorptions in the visible range. In addition, all of the group 10 and 11 metal boratranes adopt C3 symmetry both in the solid state and in solution. The central M→B interaction is found to moderately influence the degree of helicity and configurational stability of these three-bladed propellers, and DFT calculations support a dissociative pathway for the inversion process. © 2008 American Chemical Society

Efficient Palladium Catalysts Containing Original Imidazolium-Tagged Chiral Diamidophosphite Ligands for Asymmetric Allylic Substitutions in Neat Ionic Liquid

New imidazolium-tagged chiral diamidophosphite ligands, (<i>S</i>,<i>S</i>)-<b>a</b> and (<i>R</i>)-<b>b</b>, derived from (<i>S</i>,<i>S</i>)-<i>N</i>,<i>N</i>′<i>-</i>dibenzyl-1,2-cyclohexanediamine and (<i>R</i>)-<i>N</i>,<i>N</i>′-dimethyl-1,1′-binaphthyl-2,2′-diamine, respectively, and the corresponding palladium allylic complexes of general formula [PdCl­(η³-2-Me-C₃H₄)­(κ¹<i>P</i>-L)]­BF₄ (<b>1a</b>,<b>b</b>) and [Pd­(η³-2-Me-C₃H₄)­(κ¹<i>P</i>-L)₂]­(BF₄)₃ (<b>2a</b>,<b>b</b>) were synthesized and fully characterized, including the X-ray crystal structure for <b>1b</b>. These original Pd/L catalytic systems were applied in asymmetric allylic alkylation, amination, and sulfonylation using <i>rac</i>-3-acetoxy-1,3-diphenyl-1-propene as a substrate in neat ionic liquids, [bmim]­[PF₆] and [Pyr]­[NTf₂]. The best results in terms of enantioselectivity were obtained with the catalytic precursor <b>1b</b> in [Pyr]­[NTf₂]. The catalytic phase containing <b>1b</b> for the allylic amination could be recycled up to six times without significant loss of asymmetric induction