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1.
本文报道了采用场解吸电离质谱(FDMS)技术获得的膦桥过渡金属杂双核络合物系列化合物的质谱图,讨论了该系列络合物的裂解规律和离子源条件下的稳定性。结果表明,FDMS技术对研究膦桥过渡金属杂双核络合物是有效的方法。 相似文献
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Field desorption (FD) enables mass-spectrometric investigation of large organic molecules without their vaporization. The present state of our theoretical understanding of the ionization of these molecules in the adsorbed state on organic emitters is described. The special problems of the technique and prospective developments in the apparatus for future analytical problems are outlined. The present progress report concentrates on analytical studies of biochemical model compounds and degradation products from environmental chemicals and drugs. The method is particularly suitable for the detection and identification of submicrogram quantities of underivatized polar substances present in complex mixtures or pre-purified extracts from biological materials. 相似文献
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[Tc(NPh)Cl3(PPh3)2] or [Re(NPh)Cl3(PPh3)2] react with two equivalents of Na2mnt (mnt2– = 1,2‐dicyanoethene‐1,2‐dithiolate) with formation of anionic complexes of the composition [M(NPh)(mnt)2]–. The products can be isolated as large red blocks of their AsPh4+ salts. The complex anions contain square‐pyramidal coordinated metal atoms with the phenylimido ligands in apical positions. The M–N–C bonds are almost linear. A similar phenylimido complex with an additional amino group was synthesized from [Re(NC6H4‐4‐NH2)Cl3(PPh3)2]. The presence of such substituents may allow coupling of the metal complexes to biomolecules such as peptides, proteins, or sugars, provided the M=N bonds are sufficiently stable against hydrolysis. 相似文献
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[NEt4]2[Re(CO)3Br3] and [NEt4]2[Tc(CO)3Cl3] react with trimethylsilyltriphenylphosphoraneimine, Me3SiNPPh3, under exchange of the bromo ligands and the formation of cationic [M(CO)3(HNPPh3)3]+ complexes (M = Re, Tc). The required protons are abstracted from the solvent CH2Cl2. The steric bulk of the organic ligands causes a marked distortion of the established coordination polyhedra from an idealized octahedron with bond angles between neighbouring donor atoms between 81.81(8)° and 96.66(8)°. The reaction of [NEt4]2[Re(CO)3Br3] with Me3SiNP(Ph2)CH2PPh2 in CH2Cl2 yields the neutral complex [Re(CO)3Br{HNP(Ph2)CH2PPh2)], which contains a neutral, chelate‐bonded (diphenylphosphinomethyl)diphenylphosphoraneimine ligand. A similar reaction with the bifunctional phosphoraneimine Me3SiNP(Ph2)CH2(Ph2)PNSiMe3 gives only small amounts of a binuclear rhenium(I) complex of the composition [{Re(CO)3Br2}2(HNP(Ph2)CH2(Ph2)PNH)]2‐, whereas the major amount of the bis‐phosphoraneimine undergoes an intramolecular rearrangement to yield [H2NP(Ph2)NP(Ph2)CH3]Br. An X‐ray structure analysis shows a widespread delocalization of electron density over the central part of the cation. 相似文献
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本文采用FDMS和DElMS对4种新型火药进行了质谱分析,均得到了很强的分子离子峰和特征碎片峰,并对样品A进行了DEIMS的亚稳分析,得出了该类化合物的裂解规律为:M-n(NO),M-n(O),M-n(NO_2),M-n(HNO_2),M-n(OH)等。 相似文献
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M. Stichelberger D. Desbouis V. Spiwok P.A. Schubiger R. Schibli 《Journal of organometallic chemistry》2007,692(6):1255-1264
Thymidine kinases have been identified as suitable targets for non-invasive imaging of gene therapy and cancer. Thus, there is a high interest in new, reliable and inexpensive radiolabeled thymidine analogues for these applications. In this study we present the synthesis and in vitro evaluation of M(CO)3-complexes of thymidine (M = 99mTc, Re) for potential use in SPECT tumor imaging. 5′-amino-5′-deoxythymidine was derivatized at position C5′ with spacers of various lengths (∼0-30 Å) carrying tridentate metal chelating entities such as iminodiacetic acid and picolylamine-N-monoacetic acid. The nucleoside derivatives were reacted with the precursors [ReBr3(CO)3]2− and [99mTc(OH2)3(CO)3]+, respectively. The organometallic thymidine complexes have been fully characterized by means of IR, NMR and mass spectrometry. Enzyme kinetic studies revealed mixed inhibition of the human cytosolic thymidine kinase with Ki values ranging from 4.4 to 334 μM for all thymidine complexes. Competitive inhibition of herpes simplex virus type 1 thymidine kinase was only achieved when thymidine and the metal core were separated by a spacer of approximately 30 Å length. These findings were supported by in silico molecular docking and molecular dynamic experiments. 相似文献
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Dr. Xiaowei Song Dr. Qingce Zang Dr. Chao Li Dr. Tianhao Zhou Prof. Richard N. Zare 《Angewandte Chemie (International ed. in English)》2023,62(9):e202216969
We present immunoassay-based desorption electrospray ionization mass spectrometry imaging (immuno-DESI-MSI) to visualize functional macromolecules such as drug targets and cascade signaling factors. A set of boronic acid mass tags (BMTs) were synthesized to label antibodies as MSI probes. The boronic ester bond is employed to cross-link the BMT with the galactosamine-modified antibody. The BMT can be released from its tethered antibody by ultrafast cleavage of the boronic ester bond caused by the acidic condition of sprayed DESI microdroplets containing water. The fluorescent moiety enables the BMT to work in both optical and MS imaging modes. The positively charged quaternary ammonium group enhances the ionization efficiency. The introduction of the boron element also makes mass tags readily identified because of its unique isotope pattern. Immuno-DESI-MSI provides an appealing strategy to spatially map macromolecules beyond what can be observed by conventional DESI-MSI, provided antibodies are available to the targeted molecules of interest. 相似文献
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Ulrich Abram Burkhard Schmidt‐Brücken Adelheid Hagenbach Maren Hecht Reinhard Kirmse Andreas Voigt 《无机化学与普通化学杂志》2003,629(5):838-852
Terminal ‘N3—’ ligands in rhenium and technetium nitrido complexes are sufficiently nucleophilic to react with Lewis acids under formation of nitrido‐bridged compounds. The reactivity of the nucleophilic centre and the nature of the formed compounds are strongly dependent on the Lewis acid and the composition of the metal complex used. Air‐stable compounds with Re≡N‐ER3 bridges are formed when ER3 is BR3 (R = H, Cl, Br, Ethyl, Phenyl, C6F5), BCl2Ph, GaCl3, CPh3+, or PPh3. The six‐co‐ordinate rhenium(V) complexes [ReNX2(PMe2Ph)3] (X = Cl, Br), [ReN(X)(Et2dtc)(PMe2Ph)2] (Et2dtc— = diethyldithiocarbamate) and [ReN(Et2dtc)2(PMe2Ph)] have been proved to be excellent starting materials for this type of reactions, whereas the five‐co‐ordinate precursors [ReNCl2(PPh3)2], [ReN(Et2dtc)2], [ReN{Ph2P(S)NP(S)Ph2}2] or [ReNCl4]— only react with the most reactive Lewis bases of the examples mentioned above such as BCl2Ph or B(C6F5)3. The rhenium‐nitrido bond lengths remain almost unchanged by the adduct formation, whereas a significant decrease of the trans‐influence of the nitrido complexes has been observed as can be seen by a shortening of the corresponding bond lengths or dimerization of five‐co‐ordinate precursors. Electrophilic attack of the Lewis acid to a donor atom of the equatorial co‐ordination sphere of the rhenium complex results in the formation of ‘underco‐ordinate’ metal centres which resemble to di‐, tri or tetrameric units with asymmetric nitrido bridges between each two rhenium atoms. EPR spectroscopy is an excellent tool to reflect the formation of nitrido bridges at the paramagnetic (d1) [ReNX4]— core (X = F, Cl, Br, NCS). The spectral parameters derived for the products of reactions of [ReNCl4]— with various boron compounds indicate an increase of the covalency of the equatorial Re‐L bonds as a consequence of the formation of a nitrido bridge. The tendency for the formation of nitrido bridges with Lewis acids is significantly lower for technetium compounds compared to their rhenium analogues. Only a few examples with BH3 and BPhCl2 have been established. 相似文献
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《Analytical letters》2012,45(12):2637-2647
Abstract In order to determine amphetamine and metamphetamine, we have used a method never used before in the legal practice. The aim of our work was to optimize the measurement conditions for the rapid and accurate determination of amphetamine and metamphetamine. We have developed a method which makes possible the unambiguous identification of the hydrochlorides of the hallucinogens amphetamine and metamphetamine, even when these two are present simultaneously. In our work we have used the ammonium salt technique. The information available from the mass spectra (molecular ion, appearance of characteristic fragments) are dependent on the temperature of the direct sample and the ionisation energy. As a consequence, we have primarily studied the influence of the above two parameters upon the mass spectra. 相似文献
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《Analytical letters》2012,45(15):2329-2342
The synthesis, characterization, and mass spectra of oxorhenium(V) complexes with 1,2-dihydroxybenzene, 1,2,3-trihydroxybenzene, and 2,3-dihydroxynaphtalene are reported. Electrospray ionization, atmospheric pressure photoionization, and laser desorption/ionization mass spectra of the complexes showed abundant negatively charged molecular anions and low fragmentation. Calculated similarity indexes showed significant conformity between the computed and experimental isotopic patterns of selected ions and confirmed correct assignment of elemental composition to m/z values. Electrospray tandem mass spectrometry provided essential information about fragments from molecular ions of studied complexes, making it possible to distinguish among fragment ions and the ions arising from compounds present in the reaction mixture. Based on the results, mass spectrometry utilizing soft common ionization techniques is useful for monitoring complex formation reaction kinetics and the stabilities of the complexes. Representative spectra were recorded for micromolar concentrations of the analytes. 相似文献
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建立了黄酮与溶菌酶相互作用研究的强度衰减-基质辅助激光解吸离子化-质谱(Intensity fading matrix-assisted laser desorption/ionization mass spectrometry,IF-MALDI-MS)分析方法.在优化的基质DHB条件下,分别研究了木犀草素、染料木素、芹菜素、槲皮素和大豆黄素与溶菌酶相互作用,比较了溶菌酶加入前后黄酮的相对丰度的变化,并通过竞争实验的方法研究了5种黄酮与溶菌酶结合的亲和性大小.结果表明,5种黄酮与溶菌酶均存在相互作用,亲和性强弱为:木犀草素>芹菜素,染料木素>槲皮素>大豆黄素.结合5种黄酮的结构特征,讨论了黄酮的结构及其与溶菌酶亲和性的关系,发现C5位和C3’位的羟基有利于黄酮与溶菌酶的结合,C3位的羟基不利于黄酮与溶菌酶的结合.本方法具有简便,快速,高效等优点,也可以应用于其它天然产物与蛋白质的相互作用的研究. 相似文献
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电喷雾解吸电离质谱快速测定吴茱萸中生物碱 总被引:5,自引:0,他引:5
生物碱是许多中草药的活性有效成分,其含量的多少和种类的差异是导致中草药品质差异的重要因素.本文利用电喷雾解吸电离质谱(DESI-MS)能够在不需要样品预处理的前提下进行复杂基体样品分析的特点,采用酸性甲醇-水混合溶液作为喷雾试剂,在优化了的实验条件下快速获得了吴茱萸的DESI-MS指纹谱图,然后利用串联质谱对其中有重要活性的5种生物碱进行了结构鉴定.实验表明,基于固体表面解吸电离质谱分析的方法不需要萃取-分离手续,单个样品测定时间不超过1.5 min,大幅度提高了分析速度,有望在药品品质的在线监测和工艺过程控制中发挥重要作用. 相似文献
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将三氟乙酸添加到解吸电喷雾电离质谱的喷雾溶剂中,提高了对脂质的成像检测能力,使小鼠脑组织切片中能检测到的脂质种类从59种提高到71种.此外,该方法还可以促进脂质的质子化峰的形成并抑制钠和钾加合物的形成,有利于简化谱图解析过程并实现更好的定量分析.利用该方法实现了小鼠脑组织切片上多种脂质的空间相关性研究,为探索脂质间潜在的代谢途径提供了新手段,在神经学、临床等领域具有巨大的应用前景. 相似文献
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《Analytical letters》2012,45(21-22):2147-2154
Abstract Application of Spark Source Mass Spectrometry(SSMS) for the determination of hydrogen in zircaloy clad material used in nuclear reactors is reported. The advantage of SSMS lies in the fact that along with the metallic trace constituents even the nonmetallics including the gaseous impurities can also be determined in a single analysis using the photoplate detection system. The value obtained for H2 using photoplate detection system is compared with that obtained in electrical detection system in SSMS and also with the value obtained employing the conventional inert gas fusion technique. 相似文献
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为了探索生物化学、生物医学中混合寡肽的分析问题,对未衍生的混合二肽场解吸质谱进行了研究(图1和图2)。在图1图2中出现了所有二肽的准分子离子[M+H]~+,除此外还出现了[2M+H]~+、[M_(AB)+H]~+、[M_(AC)+H]~+等集聚离子,这些集聚离子能用于进一步确定各个肽的分子量。 相似文献
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Brad D. Morrical Renato Zenobi 《International journal of environmental analytical chemistry》2013,93(6):377-385
Jungfraujoch (JFJ) is considered to be a location for background free troposphere measurements. Aerosol particles collected at JFJ are analyzed to characterize adsorbed polycyclic aromatic compounds (PACs). Aerosol samples were collected from March 21 to 25, 2000 and from August 1 to 9, 2000. Samples were then analyzed by two-step laser mass spectrometry (L2MS). The mass spectra show higher relative concentrations of PACs present on samples collected during the August sampling period versus the March sampling period. L2MS data from March indicates good correlation with black carbon aerosol data measured in parallel. This suggests that long range transport of aerosol from combustion is responsible for the majority of PACs observed. Data from August unexpectedly showed markers indicative of environmental tobacco smoke (ETS). The contribution to total aerosol may be small, but the relative signal of ETS markers correlates well with the number of visitors coming daily to JFJ, pointing to a local source of ETS. 相似文献