Kevin J. Coutinho  Ron S. Dickson  George A. Koutsantonis  Brian W. Skelton  Allan H. White Prof. Dr. 《无机化学与普通化学杂志》2008,634(4):669-674

Syntheses of the array of heterobimetallic complexes [(OC)₃M(μ‐PPh₂)₂(μ‐O‐C(CHMe(CH₂)₂PPh₂)RhL], M = Cr, Mo, W, L = ^tBuNC, are described, extending the previous study of the counterpart array for L = CO. A single crystal X‐ray structure determination is reported for the M = Mo adduct, enabling comparison with its previously reported L = CO counterpart, for which an improved redetermination is also reported. In the present complex the ^tBuNC ligand is found to be much more weakly bound (Rh‐C 2.026(5) Å) than the carbonyl group it displaces (Rh‐C 1.945(2) Å) with concomitant minor impact on the remainder of the rhodium ambience.  相似文献   

    

Köhn M  Wacker R  Peters C  Schröder H  Soulère L  Breinbauer R  Niemeyer CM  Waldmann H 《Angewandte Chemie (International ed. in English)》2003,42(47):5830-5834

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Ron M. Versteegen  Rint P. Sijbesma  E. W. Meijer 《Angewandte Chemie (International ed. in English)》1999,38(19):2917-2919

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Wilhelm T. S. Huck  Ron Hulst  Peter Timmerman  Frank C. J. M. Van Veggel  David N. Reinhoudt 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1997,109(9):1046-1049

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Wim Buijs  Peter Comba  Danny Corneli  Ynze Mengerink  Ron Peters 《欧洲无机化学杂志》2001,2001(12):3151-3154

Various halogenated pyridines (2-fluoropyridine, 2-chloropyridine, 2-bromopyridine, 3-bromopyridine, 2,5-dibromopyridine, and 3,5-dibromopyridine) are subject to catalytic reduction and substitution under DOW-phenol conditions; copper(I) benzoate is shown to play a key role in these processes. In the absence of copper(I), the halogenated pyridines do not react with benzoic acid, while after precipitation of copper(I) halide the dehalogenation process stops. Marked differences are observed between the copper(I)-catalyzed dehalogenation of the halopyridines and the previously reported dehalogenation of halogenated aromatics. While the copper(I)-catalyzed substitution of haloaryl compounds by benzoate makes only a minor contribution to the overall dehalogenation process, substitution of halopyridine compounds is at least as important as the reduction reaction. Furthermore, the reaction with halopyridine compounds is regioselective, in contrast to that with halogenated aryl compounds.  相似文献   

  总被引：1，自引：0，他引：1  

Doezé RH  Maltman BA  Egan CL  Ulijn RV  Flitsch SL 《Angewandte Chemie (International ed. in English)》2004,43(24):3138-3141

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Boere IA  Robinson DJ  de Bruijn HS  Kluin J  Tilanus HW  Sterenborg HJ  de Bruin RW 《Photochemistry and photobiology》2006,82(6):1638-1644

Barrett's esophagus (BE) can experimentally be treated with 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT), in which ALA, the precursor of the endogenous photosensitizer protoporphyrin IX (PpIX) and subsequent irradiation with laser light are applied to destroy the (pre)malignant tissue. Accurate dosimetry is critical for successful ALA-PDT. Here, in vivo dosimetry and kinetics of PpIX fluorescence photobleaching were studied in a rat model of BE. The fluence and fluence rate were standardized in vivo and PpIX fluorescence was measured simultaneously at the esophageal wall during ALA-PDT and plotted against the delivered fluence rather than time. Rats with BE were administered 200 mg kg(-1) ALA (n = 17) or served as control (n = 4). Animals were irradiated with 633 nm laser light at a measured fluence rate of 75 mW cm(-2) and a fluence of 54 J cm(-2). Large differences were observed in the kinetics of PpIX fluorescence photobleaching in different animals. High PpIX fluorescence photobleaching rates corresponded with tissue ablation, whereas low rates corresponded with no damage to the epithelium. Attempts to influence tissue oxygenation by varying balloon pressure and ventilation were shown not to be directly responsible for the differences in effect. In conclusion, in vivo dosimetry is feasible in heterogeneous conditions such as BE, and PpIX fluorescence photobleaching is useful to predict the tissue response to ALA-PDT.  相似文献   

    

Sigrid Baumgarten  Ron C. Gaba  Richard B. van Breemen 《Biomedical chromatography : BMC》2012,26(12):1529-1533

Because liver cancer is rarely suitable for surgery, transcatheter arterial chemoembolization (TACE) is used for palliative therapy. In this procedure, an emulsion of doxorubicin in iodized oil is injected directly into liver tumors through a catheter positioned within the artery supplying blood flow to the tumor. At present, there is limited understanding of factors affecting the delivery and dispersion of doxorubicin within treated tumors during TACE. This study addresses the development and application of an ultrahigh‐pressure liquid chromatography–tandem mass spectrometry (UHPLC‐MS‐MS) method for rapid confirmation of drug delivery after TACE in a rabbit VX2 liver cancer model. Doxorubicin levels in liver tumors were measured using UHPLC‐MS‐MS and compared with computed tomography measured levels of iodized oil, a metric used clinically to indicate drug delivery. We found that tissue drug levels determined using UHPLC‐MS‐MS did not correlate with the regional iodized oil concentration (vehicle) within tumors following TACE, suggesting that chemotherapeutic drugs like doxorubicin spread throughout tumors, and that lack of iodized oil staining in portions of a tumor does not necessarily indicate inadequate therapy during TACE. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

    

Yuri E. M. van der Burgt  Magnus Palmblad  Hans Dalebout  Ron M. A. Heeren  André M. Deelder 《Rapid communications in mass spectrometry : RCM》2009,23(1):31-38

Electron capture dissociation (ECD) is an analytical technique in mass spectrometry (MS) that allows detailed structural study of biomolecules to gain insight in their function. In this work the ECD behavior of two peptide hormones oxytocin (OT1) and vasopressin (VP1) was studied. The results of OT1 and VP1 were compared to structural analogues OT2 and VP2, which have similar amino acid sequences but lack the tocin ring. The ECD results showed that both the fragment type (c/z versus b/y) and the cleavage sites (ring versus tail) changed upon opening of the tocin ring. All four peptides were complexed with three different transition metal cations (Zn²⁺, Ni²⁺ and Cu²⁺) and the ECD results were compared to those obtained from the doubly protonated species. The use of various metal ions yielded different cleavages sites within the same peptide. This can be an effect of the metal ion itself, or a consequence of a change in conformation as was suggested earlier. In addition, the type of fragment ion varied for each metal‐complexed peptide, which is in agreement with previous observations. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

    

Ron M. Versteegen  Rint P. Sijbesma  E. W. Meijer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1999,111(19):3095-3097

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