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61.
A new cyclic nitrone spin trap, [4-(3′,3′-dibutyl-2′-oxy-3′H-isoindol-5′-yloxy)butyl]triphenylphosphonium bromide (MitoSpin), bearing a lipophilic cation has been prepared by a route that involves a novel Parham-type lithiation-cyclization of an isocyanate to give the isoindolinone core. MitoSpin accumulates in a membrane potential dependent way in energized mitochondria and its oxidation could potentially be used in the study of oxidative stress resulting from reactive oxygen species generated in mitochondria. 相似文献
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Simon J. Bonyhady Cameron Jones Prof. Sharanappa Nembenna Dr. Andreas Stasch Dr. Alison J. Edwards Dr. Garry J. McIntyre Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(3):938-955
The preparation and characterization of a series of magnesium(II) iodide complexes incorporating β‐diketiminate ligands of varying steric bulk and denticity, namely, [(ArNCMe)2CH]? (Ar=phenyl, (PhNacnac), mesityl (MesNacnac), or 2,6‐diisopropylphenyl (Dipp, DippNacnac)), [(DippNCtBu)2CH]? (tBuNacnac), and [(DippNCMe)(Me2NCH2CH2NCMe)CH]? (DmedaNacnac) are reported. The complexes [(PhNacnac)MgI(OEt2)], [(MesNacnac)MgI(OEt2)], [(DmedaNacnac)MgI(OEt2)], [(MesNacnac)MgI(thf)], [(DippNacnac)MgI(thf)], [(tBuNacnac)MgI], and [(tBuNacnac)MgI(DMAP)] (DMAP=4‐dimethylaminopyridine) were shown to be monomeric by X‐ray crystallography. In addition, the related β‐diketiminato beryllium and calcium iodide complexes, [(MesNacnac)BeI] and [{(DippNacnac)CaI(OEt2)}2] were prepared and crystallographically characterized. The reductions of all metal(II) iodide complexes by using various reagents were attempted. In two cases these reactions led to the magnesium(I) dimers, [(MesNacnac)MgMg(MesNacnac)] and [(tBuNacnac)MgMg(tBuNacnac)]. The reduction of a 1:1 mixture of [(DippNacnac)MgI(OEt2)] and [(MesNacnac)MgI(OEt2)] with potassium gave a low yield of the crystallographically characterized complex [(DippNacnac)Mg(μ‐H)(μ‐I)Mg(MesNacnac)]. All attempts to form beryllium(I) or calcium(I) dimers by reductions of [(MesNacnac)BeI], [{(DippNacnac)CaI(OEt2)}2], or [{(tBuNacnac)CaI(thf)}2] have so far been unsuccessful. The further reactivity of the magnesium(I) complexes [(MesNacnac)MgMg(MesNacnac)] and [(tBuNacnac)MgMg(tBuNacnac)] towards a variety of Lewis bases and unsaturated organic substrates was explored. These studies led to the complexes [(MesNacnac)Mg(L)Mg(L)(MesNacnac)] (L=THF or DMAP), [(MesNacnac)Mg(μ‐AdN6Ad)Mg(MesNacnac)] (Ad=1‐adamantyl), [(tBuNacnac)Mg(μ‐AdN6Ad)Mg(tBuNacnac)], and [(MesNacnac)Mg(μ‐tBu2N2C2O2)Mg(MesNacnac)] and revealed that, in general, the reactivity of the magnesium(I) dimers is inversely proportional to their steric bulk. The preparation and characterization of [(tBuNacnac)Mg(μ‐H)2Mg(tBuNacnac)] has shown the compound to have different structural and physical properties to [(tBuNacnac)MgMg(tBuNacnac)]. Treatment of the former with DMAP has given [(tBuNacnac)Mg(H)(DMAP)], the X‐ray crystal structure of which disclosed it to be the first structurally authenticated terminal magnesium hydride complex. Although attempts to prepare [(MesNacnac)Mg(μ‐H)2Mg(MesNacnac)] were not successful, a neutron diffraction study of the corresponding magnesium(I) complex, [(MesNacnac)MgMg(MesNacnac)] confirmed that the compound is devoid of hydride ligands. 相似文献
64.
In this letter we evaluate the accuracy of the first reaction method (FRM) as commonly used to reduce the computational complexity of mesoscale Monte Carlo simulations of geminate recombination and the performance of organic photovoltaic devices. A wide range of carrier mobilities, degrees of energetic disorder, and applied electric field are considered. For the ranges of energetic disorder relevant for most polyfluorene, polythiophene, and alkoxy poly(phenylene vinylene) materials used in organic photovoltaics, the geminate separation efficiency predicted by the FRM agrees with the exact model to better than 2%. We additionally comment on the effects of equilibration on low-field geminate separation efficiency, and in doing so emphasize the importance of the energy at which geminate carriers are created upon their subsequent behavior. 相似文献
65.
Leibfarth FA Schneider Y Lynd NA Schultz A Moon B Kramer EJ Bazan GC Hawker CJ 《Journal of the American Chemical Society》2010,132(42):14706-14709
The functionalization and cross-linking of polyethylene is synthetically challenging, commonly relying on highly optimized radical based postpolymerization strategies. To address these difficulties, a norbornene monomer containing Meldrum's acid is shown to be effectively copolymerized with polyethylene using a nickel α-iminocarbaxamidato complex, providing high-melting, semicrystalline polymers with a tunable incorporation of the functional comonomer. Upon heating the copolymer to common polyethylene processing temperatures, the thermolysis of Meldrum's acid to ketene provides the desired reactive group. This simple and versatile methodology does not require small molecule radical sources or catalysts, and the dimerization of the in situ generated ketenes is shown to provide tunable cross-linking densities in polyethylene. Subsequent rheological and tensile experiments illustrate the ability to tune cross-linked polyethylene properties by comonomer incorporation and elucidate valuable structure/property relationships in these materials. This study illustrates the power of well-defined and synthetically accessible functional groups in polyolefin synthesis and functionalization. 相似文献
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67.
Sanchez-Cano C Huxley M Ducani C Hamad AE Browning MJ Navarro-Ranninger C Quiroga AG Rodger A Hannon MJ 《Dalton transactions (Cambridge, England : 2003)》2010,39(47):11365-11374
Previously a range of androgen conjugates with non-conventional platinum(II) complexes have been synthesised with the aim of enhancing cellular delivery, and which have shown increased cytotoxic activity compared with non-steroidal compounds (M. J. Hannon et al., Dalton Trans., 2010, DOI: 10.1039/c0dt00838a). To further study this, the complexes have been assessed for their ability to bind to and alter the structure of DNA. All platinum(II) complexes studied herein bind to model nucleo-bases and DNA, but to our surprise, testosterone-based complexes caused the DNA helix to undergo significant unwinding and bending, whereas non-steroidal control complexes caused minimal structural alterations. These effects are similar to those cisplatin induces on DNA structure despite the fact that these compounds produce a monofunctional lesion. This ability attributed to interactions between the DNA helix and bulky steroidal skeleton of testosterone, coupled with the enhanced cellular delivery induced by the steroid make the steroid approach an exciting way to explore non-conventional platinum drug delivery. 相似文献
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69.
Search for a standard model Higgs boson in the H→ZZ→ℓ(+)ℓ(-)νν decay channel with the ATLAS detector
Aad G Abbott B Abdallah J Abdelalim AA Abdesselam A Abdinov O Abi B Abolins M Abramowicz H Abreu H Acerbi E Acharya BS Adams DL Addy TN Adelman J Aderholz M Adomeit S Adragna P Adye T Aefsky S Aguilar-Saavedra JA Aharrouche M Ahlen SP Ahles F Ahmad A Ahsan M Aielli G Akdogan T Åkesson TP Akimoto G Akimov AV Akiyama A Alam MS Alam MA Albert J Albrand S Aleksa M Aleksandrov IN Alessandria F Alexa C Alexander G Alexandre G Alexopoulos T Alhroob M Aliev M Alimonti G Alison J Aliyev M Allport PP 《Physical review letters》2011,107(22):221802
A search for a heavy standard model Higgs boson decaying via H→ZZ→→?(+)?(-)νν, where ?=e, μ, is presented. It is based on proton-proton collision data at √s=7 TeV, collected by the ATLAS experiment at the LHC in the first half of 2011 and corresponding to an integrated luminosity of 1.04 fb(-1). The data are compared to the expected standard model backgrounds. The data and the background expectations are found to be in agreement and upper limits are placed on the Higgs boson production cross section over the entire mass window considered; in particular, the production of a standard model Higgs boson is excluded in the region 340相似文献