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91.
92.
Silvestri F Jordan M Howes K Kivala M Rivera-Fuentes P Boudon C Gisselbrecht JP Schweizer WB Seiler P Chiu M Diederich F 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(22):6088-6097
The substrate scope of the [2+2] cycloaddition-cycloreversion (CA-CR) reaction between electron-deficient (2,2-dicyanovinyl)benzene (DCVB) or (1,2,2-tricyanovinyl)benzene (TCVB) derivatives and N,N-dimethylanilino (DMA)-substituted acetylenes was investigated. The structural features of the cyanobutadiene products of these transformations were examined and the rates of selected CA-CR reactions were measured. Rate constants for reactions utilizing pentafluorinated TCVB and DCVB were found to be one to two orders of magnitude larger than those for the unsubstituted analogues. Multiple, consecutive CA-CR reactions were performed with substrates incorporating two reactive 2,2-cyanovinyl or 4-ethynylanilino sites. 1,4-Bis(2,2-dicyanovinyl)-2,3,5,6-tetrafluorobenzene and 1,4-bis[(4'-dihexylamino)phenylethynyl]benzene were selected as suitably reactive monomers for the synthesis of regular [AB] oligomers wherein the push-pull chromophores were formed in the chain-growth step. Oligomers of two types were isolated: macrocyclic [AB](n) and open-chain B[AB](n) oligomers, with n≤4. 相似文献
93.
Vitagliano L Vergara A Bonomi G Merlino A Verde C di Prisco G Howes BD Smulevich G Mazzarella L 《Journal of the American Chemical Society》2008,130(32):10527-10535
94.
Chris Binns Pilar Prieto Stephen Baker Paul Howes Ruggero Dondi Glenn Burley Leonardo Lari Roland Kr?ger Andrew Pratt Sitki Aktas John K. Mellon 《Journal of nanoparticle research》2012,14(9):1-16
In this study, efforts were placed in giving some in vitro key clues to the question on which is more efficient for the cancer hyperthermia between intracellular and extracellular modalities. Near infrared (NIR) photothermal responsive gold nanorods (GNRs) were adopted to cause cellular thermolysis either from inside or outside of cells. GNRs were synthesized with the size of 30.4?nm (in length)?×?8.4?nm (in width). Demonstrated by ICP-MS (inductively coupled plasmon mass spectroscopy), UV?CVis spectroscopy and transmission electron microscopy analyses, various cell uptake doses of nanoparticles were differentiated due to different molecular designs on GNRs surfaces and different types of cells chosen (three cancer cell lines and three normal ones). Under our continuous wavelengths (CW) NIR irradiation, it resulted that the cells which internalized GNRs died faster than the cells surrounded by GNRs. Furthermore, fluorescent images and flow cytometry data also showed that the NIR photothermal therapeutic effect was greater when the amount of internalized GNRs per cell was larger. Generally speaking, the GNRs assisted intracellular hyperthermia exhibited more precise and efficient control on the selective cancer ablation. To a larger degree, such a relationship between GNRs distribution and hyperthermia efficiency might be applied to wider spectra of cell types and heat-producing nanoparticles, which provided a promise for future cancer thermal therapeutic designs. 相似文献
95.
Dr. Kara Howes Dr. Abdelhalim Belbakra Dr. Andrea Listorti Dr. W. Bernd Schweizer Dr. Philippe Reutenauer Dr. José‐Lorenzo Alonso‐Gómez Dr. Claudio Chiorboli Lorenz M. Urner Dr. Jean‐Paul Gisselbrecht Prof. Dr. Corinne Boudon Dr. Nicola Armaroli Prof. Dr. François Diederich 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(1):202-216
The synthesis, electrochemical, and photophysical properties of five multicomponent systems featuring a ZnII porphyrin (ZnP) linked to one or two anilino donor‐substituted pentacyano‐ (PCBD) or tetracyanobuta‐1,3‐dienes (TCBD), with and without an interchromophoric bridging spacer (S), are reported: ZnP‐S‐PCBD ( 1 ), ZnP‐S‐TCBD ( 2 ), ZnP‐TCBD ( 3 ), ZnP‐(S‐PCBD)2 ( 4 ), and ZnP‐(S‐TCBD)2 ( 5 ). By means of steady‐state and time‐resolved absorption and luminescence spectroscopy (RT and 77 K), photoinduced intramolecular energy and electron transfer processes are evidenced, upon excitation of the porphyrin unit. In systems equipped with the strongest acceptor PCBD and the spacer ( 1 , 4 ), no evidence of electron transfer is found in toluene, suggesting ZnP→PCBD energy transfer, followed by ultrafast (<10 ps) intrinsic deactivation of the PCBD moiety. In the analogous systems with the weaker acceptor TCBD ( 2 , 5 ), photoinduced electron transfer occurs in benzonitrile, generating a charge‐separated (CS) state lasting 2.3 μs. Such a long lifetime, in light of the high Gibbs free energy for charge recombination (ΔGCR=?1.39 eV), suggests a back‐electron transfer process occurring in the so‐called Marcus inverted region. Notably, in system 3 lacking the interchromophoric spacer, photoinduced charge separation followed by charge recombination occur within 20 ps. This is a consequence of the close vicinity of the donor–acceptor partners and of a virtually activationless electron transfer process. These results indicate that the strongly electron‐accepting cyanobuta‐1,3‐dienes might become promising alternatives to quinone‐, perylenediimide‐, and fullerene‐derived acceptors in multicomponent modules featuring photoinduced electron transfer. 相似文献
96.
Clauwaert KM Van Bocxlaer JF Major HJ Claereboudt JA Lambert WE Van den Eeckhout EM Van Peteghem CH De Leenheer AP 《Rapid communications in mass spectrometry : RCM》1999,13(14):1540-1545
This paper describes the investigation of the potential of a quadrupole orthogonal acceleration time-of-flight mass spectrometer (Q-TOF) equipped with an atmospheric pressure ionisation interface for quantitative measurements of small molecules separated by reversed phase liquid chromatography. To this end, the detection limits and linear dynamic range in particular were studied in an LC/MS/MS experiment using 3,4-methylenedioxymethamphetamine standards and 3,4-methylenedioxyethylamphetamine for internal standardisation. In a second phase, the experiment was repeated with real biological extracts (whole blood, serum, and vitreous humour). A calibration for 3,4-methylenedioxymethamphetamine and its metabolite 3,4-methylenedioxyamphetamine was prepared in each of these matrices again using 3,4-methylenedioxyethylamphetamine as internal standard. The resulting quantitative data were compared with those obtained by liquid chromatography with fluorescence detection for the same extracts. The Q-TOF results revealed excellent sensitivity and a linear dynamic range of nearly four decades (2-10 000 pg on-column, r(2) = 0.9998, 1/x weighting). Furthermore, all the calibration curves prepared in biological material were superimposable, LC/MS/MS and LC-fluorescence, and the quantitative results for actual samples compared very favourably. It was concluded that the Q-TOF achieves a linear dynamic range for quantitative LC/MS/MS work exceeding that of fluorescence detection and at much better absolute sensitivity. Copyright 1999 John Wiley & Sons, Ltd. 相似文献